BERKELEY^ LID-^ARY unit- •.■i-r Of CALI/Or\NIA Pentlancf s Studeiits MaiuLals. PRACTICAL OPHTHALMOLOGY. M"SQl"AM ALRD SATIRA, ALILD SAI'IENTIA DIC'IT. MAN UAL OF PRACTICAL OPHTHALMOLOGY GEORGE A. BERRY, M.B., F.R.C.S.Ed. SENIOR OPHTHALMIC SUKGEON, ROYAL INFIRMARY ; SURGEON', EDINBURGH EVE dispensary; OrHTHALMIC SURGEON, ROYAL HOSPITAL FOR SICK CHILDREN ; LECTURER ON OPHTHALMOLOGY, UNIVERSITY OF EDINBUKGH ly/TH 223 ILLUSTRATIONS MOSTLY FROM ORIGINAL DRAllTNGS EDINBURCiH AND LONDON YOUNG J. PENTLAND 1904 OPTOWnnY UBRARt KOIXBUROII : rKINTEl) FOR YOUNG .'. rKNTLAXli, 11 TKX lOT I'LACE, AM> 38 WKST SM1TIIKIEM>, LONDON", E.C, BY MOKRISOX AND GIBU Ll.MlTRIi. {All rlyhts rrsenrd.) PREFACE. Ophthalmology has long- held a foremost place amongst the various branches of Medicine. In diagnosis, as well as in treat- ment, it had already attained to a high degree of precision at a time when modern scientific methods had as yet barely begun to foreshadow the results which they are now almost daily achieving in other departments. Having thus early taken a leading position, the possibilities of further advance seem in the meantime to have been propor- tionately restricted. Coincident with the rapid strides made in surgery generally, and with the many discoveries which seem not unlikely to lead eventually to real therapeutic advances in internal medicine. Ophthalmology has practically been at a standstill. This being so, and as there are already not a few text-books on diseases of the eye, an addition to their number can hardly claim to be called for because of the latest developments of the subject being either very extensive or very important. A large experience as a teacher has, however, shown me that an adequate appreciation of the nature and treatment of even the commoner forms of eye disease is far from being general. I venture to hope, therefore, that there may ])e room for a treatise which is both short and essentially practical, and which, while representing without unnecessary detail current opinions as to pathology, gives expression to the author's individual experience as regards diagnosis and treatment. Edinburgh, June 1904. 41^ COI^TENTS. SECTION L CHAPTER I. General Remarks on Eye Operations. PAGE Instruments, Antiseptics, etc. ....... 3 CHAPTER II. Examination of the Eye. Preliminary Objective Examination : Inspection of the Lids — In- spection of the Cornea — Intra-ocular Tension — The External Muscles — Convergence. Subjective Examinations : Visual Acuity — Snellen's Test Tyjies — Light Sense — Vision of the Peripheral Portions of the Retina. Subjective Sensations : Pain — Diplopia — Metamorphopsia — Scotomata — Sensations of Light and Colour — Test for the Presence of Binocular Vision. Further Objective Examination : Oblique Focal Illumination — Examination with the Mirror alone. Normal Fundus Oculi as seen with the Ophthalmoscope — The Retina — The Optic Nerve — Physiological Excavation of the Disc — The Normal Choroid 8 CHAPTER III. Diseases of the Eyelids. lutroductory — Blepharitis — Hordeolum or Stye — MoUuscum Con- tagiosum — Warts, Papillomata, and Translucent Cysts — Herpes Frontalis— Xanthelasma — Eczema — Milium — Chala- zion or Tarsal Cyst — Chalky Infarcts — Trichiasis — Siiasmodic CONTENTS. I'AOK Entropion — Cicatririal Eiitroition — Ei-tropion — Epicantluis — Ptosis — Nictitatio — Blepharospasm — Oedema of the Lids — Abscess of tlie Lid— Dermoid Cj'sts— Xaivi of the Lids— Rodent Ulcers and Epitlieliomata — Chancre and Vaccine Pocks — Sar- coma of the Lid — Colohonia — Hlepliarophimosis — Anchyloldc- pliaron — Symbleiiharon ........ i'^ CHAPTEll IV. Diseases of the Lachrymal Apparatus. Affections of the Lachrymal Gland — Simple Hypertrophy or Adenoma of the Laclnymal Gland — Fistula of the Lachrymal Gland — Malignant Tumours — Dacryops — Diseases of the Tear Passages — Poh'pi or Papillomata — Inflammation of the Tear Sac — Acute Purulent Dacryocystitis ..... 77 CHAPTER V. Diseases of the Conjunctiva. The Normal Conjunctiva — Congestion — Conjunctivitis — Spring Catarrh — Purulent Conjunctivitis — Ophthalmia Xeonatorum — Phlj'ctenular Conjunctivitis — Diphtheritic Conjunctivitis — Trachoma — Amj'loid Degeneration of the Conjunctiva — Essential Shrinking of the Conjunctiva — Ecchymosis — Emphy- sema — Pterygium — Pinguecula— Injuries — Foreign Bodies in the Conjunctiva — Electric Light Ophthalmia — Snow-blind- ness — Lymphangiectasis of the Conjunctiva — Tumours and other Affections v^O CHAPTER VI. Diseases of the Cornea and Sclera. General Remarks on Inflammation of the Cornea — Primary Kera- titis — Corneal Ulceration. Special Forms of Primar}- Kera- titis : Phlyctenular Keratitis — Fascicular Keratitis — Pannus — Hypojiyon Keratitis — Dendriform (Mycotic) Keratitis — Clear Corneal Ulcers — Marginal Ring-shaped Ulcer — Mooren's Rodent Ulcer — Vesicular Keratitis. Secondary Keratitis — Neuro-paralytic Keratitis. Non-inflammatorj^ and Degenera- tive Changes in the Cornea : Transverse Calcareous Film — Arcus Senilis — Conical Cornea. Tumours of the Cornea : CONTEXTS. Dermoid Cyst — Fibroma — Malignant Tumours. Congenital Malformations of the Cornea — Injuries to the Cornea — Deposits in the Cornea — Sclero-corneal Ruptures — Tattooing of the Cornea — Seleritis ....... 136 CHAPTER VII. Diseases of the Crystalline Lexs. Introductory — Cataract — After -cataract — Congenital Cataract — Capsular Cataract — Traumatic Cataract — Glass-blowers' Cataract — Cataract Operations — Cataract Extraction with- out Iridectomy — Operations for After-cataract — Dislocation of the Lens 189 CHAPTER VIII. Diseases of the Retina and Optic Xerve. Diseases of the Retina — Hypersemia — Ansemia — Retinal H;«mor- rliages — Retinitis — Retinitis Pigmentosa — Congenital Pig- mentation of the Retina — Retinitis Proliferans — Embolism of the Central Artery of the Retina — Detachment of the Retina — Opaque Nerve Fibres iu the Retina — Retinal Changes pro- duced by Strong Light. Diseases of the 0})tic Nerve : Optic Neuritis — Atrophy of the Optic Nerve ..... 234 CHAPTER IX. Diseases of the Iris and Ciliary Body. The Iris — Hyperremia of tlie Iris — Iritis — Rheumatic Iritis — Gonor- rhceal Iritis — Syphilitic Iritis — Serous Iritis — Traumatic Iritis — Tuberculous Iritis — Cyclitis — Tumours of the Iris — Altera- tions in the Iris produced by Injury- — Congenital Anomalies of the Iris — Anterior Chamber ...... 274 CHAPTER X. Diseases of the Choroid and Vitreous. The Choroid — Choroiditis — Disseminated Choroiditis — Senile Central Choroiditis — Syphilitic Choroiditis — Posterior Sclero- choroiditis — Purulent Choroiditis — Rupture of tlie Choroid — CONTENTS. PAOB Coloboma of the Choruid — Tubercle of the Choroid — Hiemor- rliages in the Choroid — Ossification of the Choroid — Diseases of tlie Vitreous — Opacities of the Vitreous — Persistent Hyaloid Artery — Cysticercus in the Vitreous 307 CHAPTER XL Foreic;n Bodies in the Eye. Foreign Bodies in the Anterior Chamber — Foreign Bodies in the Iris — Foreign Bodies in the Posterior Aqueous Chamber — Foreign Bodies in the Lens — Foreign Bodies in the Posterior Section of the Eye 336 CHAPTER XII. Sympathetic Ophthalmitis. Introductory — Sympathetic Irritation — Causes of Sympathetic Ophthalmitis — Treatment — Prevention — Evisceration of the (rlobe— Enucleation of the Eyeball 348 CHAPTER XIII. Glaucoma. Introductory — Primary Glaucoma — Premonitory Symptoms — Dilatation of the Pupil — Haziness of the Cornea — Shallowness of the Anterior Chamber — Enlargement of Episcleral Veins — Excavation of the Papilla — Spontaneous Pulsation of the Retinal Arteries — The Acuteness of Vision — Restriction of the Field of Vision — Photopsia — Antesthesia of the Cornea — Pain — Diagnosis — Secondary Glaucoma — Hemorrhagic Glau- coma — Prognosis — Treatment ...... 360 CHAPTER XIV. Intra-ocular Tumours. Sarcoma of the Choroid and Ciliary Body — (ilioma of the Retina . 385 CONTENTS. xi CHAPTER XV. Diseases of the Orbit. PAOK IiiHammation of the Orbit : Orbital Periostitis — Orbital Cellulitis. Tumours of the Orbit : Tumours of the Bony Wall of the Orbit — Vascular Tumours of the Orbit — Tuniours of the Con- nective Tissue, etc., of the Orbit — Malignant Tumours — Tumours of the Optic Nerve. Tumours which Extend to the Orbit from Adjacent Parts : Encephalocele — Nasal Polypi — Tumours of the Lids and Skin of the Face — Aneurysm of the Orbit — Injuries to the Orbit : Bleeding into Tenon's Capsule. Foreign Bodies in the Orbit — Graves' Disease — Enophthalmos —Shrinking of the Orbit 395 CHAPTER XVI. Amblyopia and other Anomalies of Vision. Introductory — Congenital Amblyopia — Simulated Amblyopia — Amblyopia and Amaurosis due to Changes at the Visual Centres, etc. — Central Toxic Amblyopia — Hysterical Ambly- opia and Amaurosis — Subjective Sensations of Light and Colour — Idiopathic Night Blindness — Muscae Volitantes — Colour Blindness — Homonymous Hemianopia — Bi-temporal Hemianopia .......... 412 SECTION 11. CHAPTER XVII. Errors of Refraction and Accommodation. Emmetropia, Myopia, and Hypermetropia — Spherical Lenses — Use of Spherical Lenses in Ametropia — Numbering of Lenses — Accommodation — Presbyopia — Measurement of Ametropia — Hypermetropia — Myopia — ■ Astigmatism — Headaches due to Astigmatism — Irregular Astigmatism — Action of Prisms- Anomalies of Accommodation : Paralysis of Accommodation — Spasm of Accommodation ....... 439 xii CONTENTS. CHAPTER XVIII. . Affections of the Oculo-motor Muscles. I'AOK PhysiologiL'al and Introductory — Associated Movements — Con- vergence — Combined Movements, Associated and Convergent — Accommodation and Convergence — Latent Positions — Para- lysis of Ocnlar Muscles — Relative Frequency of Different Ocular Paralyses — Simultaneous Paralysis of Sevei'al Muscles of One or Both Eyes — Paralysis of the External Rectus — Paralysis of the Superior Oblique Muscle — Paralysis of the Inferior Rectus — Paralysis of tlie Superior Rectus — Paralysis of the Inferior Oblique — Paralysis of the Internal Rectus — Paralysis of the Third Nerve — Spasms of Ocular Muscles — Concomitant Strabismus — Convergent Strabismus — Divergent Strabismus — Strabismus Operations — Operation for Advance- ment of a Rectus Muscle — Effect of Tenotomy and Advance- ment — Nystagmus — Muscular Asthenopia .... 493 INDEX 566 LIST OF ILLUSTEATIOTsTS. KIG. 1. 8. 9. •10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. vessels, etc. Drum for testing the jioints and cutting edges of eye instrument Mr. Priestley Smith's balance . Desmarres' retractor ..... Diagram of visual angle .... Curve of average visual acuity at different ages in the case o healthy eyes (after Boernia) . Diagram showing horizontal extent of field of v Self- registering perimeter (M 'Hardy) Perimeter chart of field of vision Field of vision taken by Bjerrum's method Binocular corneal microscope (Czapski) Normal fundus oc;ili .... Showing ophthalmoscopic appearance which may be presented by the normal macula lutea . Normal discs, showing different arrangement of Physiological excavation of disc (after Frost) Blepharitis ...... From a case of severe blepharitis Shows round swelling in upper lid caused by large tarsal cyst Shows the appearance on the conjunctival surface of the same tarsal cyst ...... From a case of trichiasis .... Snellen's clamp ..... Showing position of threads in Snellen's operation before and after knotting (after Fuchs) ...... Conjunctival ectropion of lower lid ..... Cicatricial ectropion of the upper lid .... Ptosis operation : shows the position of the incision in the eye brow, of the loops on the skin surface, and liy the dotted line the extent of the pouch of undermined skin Ptosis operation : shows in section the course of the sutures before and after they are pulled tight .... Primary syphilitic sore of upper lid . Case showing slight degree of symblepharon of the lower lid PAGE 4 5 10 11 13 15 17 18 19 28 33 34 37 41 45 47 52 63 66 67 70 70 73 74 XIV LIST OF ILLUSTRATIONS. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. From a ca.se of almost complete symblepharon . Teale's operation for .symblepharon . Transverse .section of face ..... Weber's canaliculus knife ..... Operation of slitting canaliculus Acute dacryocystitis ..... Showing Kocli-Wecks bacilli .... Showing Morax diplo-bacilli .... Conjunctivitis with marked swelling of the follicles Buller's shield ....... Phlj^ctcnular conjunctivitis .... Pustular conJTinctivitis ..... Canthoplasty (after Wecker) .... Canthoidastj' (after Kuhnt) .... Kuap]i's roller forceps ..... Dr. Chalmers Jamieson's rasp .... Pterygium ....... Lymph angiectasis of the conjunctiva Case of dermoid cyst of conjunctiva . Case of melanoid sarcoma of the conjunctiva Case showing extensive superficial vascularisation and ulceration of the cornea ...... Anterior .synechia ..... Case of staphyloma ..... Thermo-cautery ..... Galvano -cautery ..... Case of partial staphyloma of the cornea for which has been done ..... Fascicular keratitis ..... Showing the condition of pannus in the u]i]ier porl cornea, also cicatrices in the conjnnctiva of the upper lid, in a case of trachoma ..... Strumous pannus ...... Case of small infected corneal ulcer with hj-poiiyon Case showing irregularly shaped spreading margin of infected corneal ulcer with hypopyon (hyiiojiyon keratitis) Case showing an extensive superficial ulceration of the dendritic type . . • •.-.•. From a case of non-vascularised interstitial keratitis . From a case of diffuse interstitial keratitis with dense vascularisa- tion at upper margin of cornea ...... Vascularised interstitial keratitis ...... Hutchin.son's teeth ......... Transverse calcareous band of cornea ..... Conical cornea l-AOK 75 76 78 80 81 83 94 95 102 108 113 114 119 120 126 127 129 133 . 134 135 d ulceratioi 137 138 139 149 150 1 iridectomj 151 156 rtion of tin pper lid, ii 157 158 159 160 162 166 166 167 168 171 173 LIST OF ILLUSTRATIONS. FIG. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100, 101. 102. 103. 104. 105. 106. Dermoid cyst of cornea .... From a case of corneal fibroma Corneal spud ..... After Wecker ...... Grooved tattooing needle Tattooing needles ..... Superficial scleritis ..... Changes produced by long-continued scleritis Ulcers of the sclera .... Small A'olkniann's spoon Case of incipient senile cataract Case showing the result of the operation of iridectomy in ojiening up a pupil Avhich had become occluded Case of lamellar cataract ; oblique illumination Lamellar cataract ; ophthalmoscopic illumination Showing histological appearance of capsular cataract in section (after Fuchs) Stationary (puuctiform) cataract Case of traumatic cataract Cataract stop-needle .... Cataract scoop ..... a, Spring speculum ; h, fixation forceps . a, Graefe's knife ; h, tortoise-shell scoop ; c, cystotome a, Iris hook ; b, iris foi'ceps Iris scissors ...... a, Wire vectis ; h, tortoise-shell spud ; c, wire elevator Showing method of performing section for cataract extraction Lens escaping through incision .... Double wire gauze protector ..... Pagenstecher's spoon ...... Capsule forceps ....... Small knife used for discission .... Showing the clear pupil got after a needling operation Iridotomy .scissors ...... From a case in Avhich iridotomy has been done Cystoid cicatrix ....... Traumatic subluxation of the lens .... Case of idiopathic outward dislocation of the lens . From a case of coloboma of the lens Retinal hfemorrhages ...... Post-hsemon-hagic development of fibrous tissue in the super ficial layers of the retina (after "Wecker and Masselon) From a ca.se of sub-hyaloid hremorrhage which has undergone partial absorption .... xvi LIST OF ILLUSTIIATIOXS. no. I'AOK 107. From a tyjiical case of albuminuric retinitis (after Wecker and Massclon) " . . . . 243 lOS. Extensive retinal clianges in a case of albuminuric retinitis at a late stage .......... 245 109. Diabetic retinitis (after Wecker and Massclon) . . 246 110. From a case of retinitis pigmentosa ..... 248 111. ,, ,, ,, 249 112. Congenital pigmentation of the retina ..... 2.52 113. Appearances in embolism of the central artery of the retina . 254 114. Changes caused l)y partial embolism ..... 255 115. Detachment of retina ........ 257 116. Case of detachment of the retina, with rupture . . . 260 117. Opaque nerve fibres (after Frost) ...... 262 118. Early stage of optic neuritis ....... 264 119. Later stage of optic neuritis ....... 265 120. Irregular dilatation of the pupil under atropine caused by synechia; .......... 278 121. Iris bombe, with exudation on lens capsule .... 280 122. Iris bombe shown in section (after Fuclis) .... 281 123. Case of gummatous iritis ....... 288 124. ,, ,, 290 125. Case of serous irido-cyclitis 292 126. Case of tuberculous mass in iris and anterior chamber (granu- loma iridis) ......... 295 127. Case of iris cyst ......... 299 128. Case showing separation of iris from its peripheral margin (irido-dialysis) ......... 301 129. Congenital coloboma of the iris (downwards and inwards) . 302 130. ,, ,, ,, (downwards) . . . .303 131. Double coloboma of the iris with correctopia .... 304 132. Case of capsulo-pupillary membrane with surrounding white ("paint ") spots on cajisule. ...... 305 133. Disseminated choroiditis ....... 309 134. Recent disseminated choroiditis ...... 310 135. Circumscril>cd central choroido-retinitis in ati'ophic stage (after "Wccker and Masselon) ....... 311 136. Disseminated choroiditis showing marked pigmentary clianges .......... 312 137. Showing distortion of parallel lines round i)oint of fi.xatiou (micropsia) . . . . . . . . . .313 138. Showing distortion of parallel lines in the case of macropsia . 313 139. Senile central choroiditis, with circumpupillary atrophy , . 315 140. Difl'use acute choroiditis ........ 316 141. Choroiditis, with marked disturbance of retinal pigment in macular region ......... 317 LIST OF ILLUSTRATIONS. xvii FIG. TAQK 142. Showing a recent patch of central choroido-retinitis (after Frost) 318 143. Showing a large patch of central choroido-retinitis in the advanced atrophic stages (after Frost) . . . . .319 144. From a case showing atrophic crescent at lower portion of disc 320 145. From a case of progressive myopia, showing staphyloma posti- cnm and macular choroido-retinal changes .... 321 146. Ruptm-e of choroid . ........ 326 147. Coloboma of choroid 327 148. Showing formation of fine blood vessels in vitreous (after Frost) 332 149. Evisceration scoop ......... 3.56 l.'iO. Instrument for inserting glass glolje into eviscerated eyeball . 357 151. Enucleation scissors ........ 358 152. From a case of glaucoma ....... 365 153. Longitudinal section through papilla with glaucomatous ex- cavation, showing cause of ophthalmoscopic appearances (after Fuchs) 366 154. Diagrammatic representation of the diflerent forms of excava- tion (after Fuchs) ........ 367 155. Typical defect of field of vision, from a case of glaucoma . . 369 156. Glaucoma field, by Bjerrum's method ..... 370 157. Keratome 380 158. Case of sarcoma of the choroid ...... 388 159. From a case of sarcoma of the choroid in the second stage . 389 160. Case of sarcoma of the choroid ...... 389 161. Section of eye filled with a melanotic sarcoma in the third stage, after perforation has taken place .... 390 162. Section through eye and through the middle of a large glioma of the retina which has begun to invade the optic nerve . 392 163. Section through eye and through large glioma of the retina which entirely filled the vitreous chamber and had under- gone extensive degenerative changes ..... 393 164. Glioma of the retina, complicated with " pseudo-glioma " . 393 165. From a case of syphilitic gumma at the upper and outer margin of the orbit ..... ... 396 166. From a case of sarcoma of the orbit causing considerable proptosis 401 167. Aneurysm of the orbit ........ 404 168. Piece of clay pipe stem removed from the orbit . . . 407 169. Showing, by shaded area, shape and position of scotomata in central toxic amblyopia • . . . . . . .417 170. Fields of vision from a case of homonymous hemiauopia . . 433 171. Fields of vision from a case of temporal hemiauopia . . 434 172. Showing the complete focussing of parallel rays in the case of emmetropia, and incomplete focussing in hypermetropia and myopia 440 b xviii LIST OF ILLUSTRATIONS. FIO. I'AOK 173. Showiug the longer refracting power of tlie more higlilj' curved cornea . . . . . ... . . .440 174. Different forms of convex and concave spherical lenses , . 441 17r). Action of a concave lens in front of the eye .... 443 176. Showing action of a convex lens placed in front of the eye . 443 177. Diagram sliowing position of lens, etc., in eye at rest and in accommodated eye (after Fiichs) ...... 447 178. Donders' curve of range of accommodation (after Nagel) . . 449 179. Sliowing the manner in whicli the action of a concave lens can be overcome by alteration in tlic curvature of the crystalline lens 450 180. Donders' curve of relative accommodation in the case of an emmetropc, aet. 15 ....... . 452 181. To illustrate the estimation of refraction by direct ophthalmo- scopic examination ........ 460 182. Curve representing the frequency of different degrees of re- fractive anomalies in the literate and the illiterate (after Tscherning, from examination of conscripts) . . . 470 183. Position of anterior and posterior focal lines in astigmatism . 473 184. Cylindrical lenses 474 185. Snellen's test for astigmatism ...... 476 186. Javal's ophthalmometer ........ 477 187. \Corneal images produced in examination witli ophthalmo- ("478 188. J meter U7S 189. Placido's disc 479 190. Distortion of Placido's rings on reflection from a cornea with irregular astigmatism ........ 485 191. Snellen's spectacle frame ....... 486 192. Position of prisms causing adduction and diminishing the necessity for abduction ....... 486 193. Position of prisms causing abduction and diminishing the necessity for adduction ....... 487 194. To show the manner in which orthoscopic lenses are got . 488 195. Axes of rotation of ocular muscles ...... 494 196. Diagram showing movement of cornea produced by each muscle separately . . . . . . . . . .495 197. Showing the deviation -which each eye tends to undergo under an impulse to convergence, and the deviations of the two eyes laterally under an impulse to associated lateral move- ment 497 198. To show diagrammatically the measurement of convergence in metre-angles ......... 498 199. Showing the manner in which deviations are measured on a tangent scale by means of the Maddox rod .... 499 200. Maddox rod 500 LIST OF ILLUSTRATIONS. FIG. 201. 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 213. 214. 215. 216. 217. 218. 219. 220. 221. 222. 223. Portion of a taiigeut scale graduated in metre angles for a fixation distance of a J metre ...... Latent position in various states of refraction and accommodation Shows manner of projection in abnormal convergence of right eye (after Alf. Graefe) ....... Shows manner of projection in abnormal divergence Position of double images in paralysis of right external rectus ,, ,, ,, superior oblique ,, ,, ,, inferior rectus . , , , , , , superior rectus Paralysis of right inferior obliqiie ...... Shows the manner in which the divergence is equally distri- buted over both eyes, but owing to the requirements of fixation manifests itself in the one eye only Strabismus hook ; strabismus scissors ..... Prince's advancement forceps ....... .^)01 504 505 506 507 508 509 510 511 512 513 514 518 519 524 525 526 526 527 542 549 550 552 SECTION I. DISEASES OF THE EYE. CHAPTER I. GENERAL REMARKS ON EYE OPERATIONS. Operations are performed ou the eye, or its appendages, with various objects in view. The most important, and, when suc- cessful, also the most satisfactory operations, are those which aim at the improvement, or at the prevention of any threatened deterioration, of vision. Some operations are performed solely or mainly for the relief of pain ; others, again, seek to remove diseased conditions which endanger life, or to remedy deformities which entail danger to the eye, while some are mainly intended to have a cosmetic eifect. The following general remarks as to the precautions which should be taken in all cases will serve to obviate too much repetition. All the instruments used in eye o2)erations must be absolutely clean. They must not only be aseptic, but free from rust, blood stains, or any foreign mattei". This applies most urgently to such as are, for any purpose, introduced into the eye. Any little piece of foreign matter, even though aseptic, if it becomes lodged within the eye, is capable of seriously impairing the success of an operation. Little bits of cotton or linen fibre may easily escape detection, and for this reason the instruments should not be rubbed with lint, cotton wool, or any material from which fine fibres might become detached. In.sti-umeuts may be rendered asei)tic in various ways, and it may not always be possible to adopt the same method. Some antiseptics, though sufficiently strong, spoil the steel, others are irritating to the eye. Boiling water, or a 5 per cent, solution of carbolic acid, are the most practically useful. If carbolic acid be employed, GENERAL REMARKS ON EYE OPERATIONS. the instruments must be transferred to some non-irritating solution before they are used. For this purpose boracic acid, in the strength of 1 to 50, is useful, or sterilised water alone. Besides being clean and aseptic, it is of considerable ini- l>ortance to see that the cutting instruments — knives, scissors, needles, etc. — are sharp. A sharp instrument is a desideratum in most surgical o})erations, but it is very essential often to the success of an operation performed on the eye, as not only is the manipulation of a sharp instrument much easier, but the greater dragging, bruising, and stretching, which may be caused by blunt steel, is not favourable to healing by fu'st intention, and may give rise to troublesome irritation. At the same time, as the vitality of the tissues is interfered with to a greater extent than in the case of clean-cut wounds, the danger of septic inoculation from any existing cause is increased. r/« ^ The points and edges of the f H H "' J, knives should be tested im- mediately before they are used. This is best done with a little piece of thin kid leather kept tightly stretched by an assist- ant, or stretched across a small drum made for the purpose. To a sufficiently sharp point this should offer no appreciable resistance, and the keenness of the edge may be inferred from the ease with which the leather is cut by it. The resistance of point and cutting edge may be determined in grammes by means of the balance invented by Mr. Priestley Smith. A good cataract knife, for instance, should have a point which pierces the kid when the counter- weight stands at 1 grm., while every part of its cutting edge should not require more than 8 grms. pressure to pass through the drum (see Fig. 2). Scissors, besides being sharp, should have their blades sufficiently tightly screwed together to cut readily at the points. It is necessary to have a good light on the eye lohilst ojyer- ating. The table or couch must therefore be so placed that the operator and his assistants do not intercept the light, which should preferably come from one side alone. When artificial light is required, the rays from the source may be focussed on the eye by means of a large convex lens held by an assistant. Fig. 1. — Drum for testing the poiuts aud cutting edges of eye iustru- ments. GENERAL REMARKS ON EYE OPERATIONS. 5 During an operation on the eye itself care must be taken that the patient's head is firmly held. With one hand of an assistant on either side of the head it may be securely fixed. Another plan, often adopted, is for an assistant on either side to hold one of the patient's ears, or the two ends of a cloth passed over his forehead. Cocaine has in great measure done away with the employment of general anaesthesia in eye operations. The more important operations for the improvement of vision can now generally be Fig. 2. — Mr. Priestley Smitli's balance. a. Arrangement for testing point. | b. For testing cutting edge. performed with the aid of cocaine, without causing any pain. A solution of hydrochlorate of cocaine, of a strength varying from 2 per cent, to 10 per cent., is used to drop into the conjunctival sac. The solution should be kept sterilised, or made up with some antiseptic, so as to obviate the possibility of introducing any micro-organisms into the eye. When the stronger solutions are used, the point of the finger should be pressed against the skin over the tear sac to jjrevent the cocaine passing down into the nose. The patient should be told to keep his eye closed after the drops have been applied. If this is not done, there is a G GENERAL REMARKS OX EYE OPERATIONS. tendency to a raiud desiccation of the surface layers of the cornea, on account of the insensibility which the anaesthetic pro- duces checking the normal blinking, and probably also the flow of the natural lubricants. The value of antisej^tics in eye operations is now so definitely established that it is iuexcusal)le not to make use of them. Septic inoculations cannot invariably be avoided by such anti- septic precautions as it is possijjle to take, although their fre- quency can be greatly diminished. The reason of this is that the worst sources of danger are not external to the eye, but in the eye itself. The use of antiseptic applications in the manner about to be described, and the attention to absolute cleanliness and asepticity in the instruments, already insisted upon, is no doubt sufficient to j^revent the possibility of infection from without. It is otherwise, however, with any micro-organisms which may be lodged in the conjunctival sac, or which may find their way into it from the tear passages. They cannot be destroyed with certainty, and the tying up of the eye even with an antiseptic bandage not only does not exclude them, but rather tends, owing to the retention of the secretions, to favour their development. In cases, therefore, where their existence is more than usually obvious, as where there is a chronic conjunc- tivitis or bleunorrhoea of the sac, it is necessary to adopt special antiseptic precautions, and sometimes, if possible, to defer oper- ating until there is reason to believe that such local sources of danger have been removed or mitigated. Often it is advisable to make a bacteriological examination of the conjunctival secre- tion before proceeding to operate. The most useful antiseptics for local application are solutions of corrosive sublimate, and iodoform. The former is mostly used in the strength of 1 to 5000. In this dilution it is almost always found to be non-irritating, though cases do occasionally occur where some irritation is caused even by such a weak solu- tion. According to bacteriologists, iodoform is a very poor anti- septic. No doubt this is the case, but it has the advantage of remaining longer in situ, and of, to some extent, acting as a cement between the lips of a wound, properties which, partly at all events, make up for its feebler antiseptic ones. A stronger non-irritating antiseptic of the same kind is a desideratum which has not yet been discovered. Before })erforming any oi)eration, the conjunctival sac should be thoroughly washed out with corrosive sublimate solution, and the surrounding skin, eyelashes, and eyebrows also carefully cleansed. From time to time, too, during an operation, the GENERAL REMARKS ON EYE OPERATIONS. 7 lotion may be brought in contact with the eye, either by pouring it in a small stream from a narrow-necked bottle, or by squeez- ing it from a piece of absorbent cotton wool. The antiseptic lotion probably acts in two ways — first as a germicide, and secondly by washing away from the wound the secretions which contain the germs. It is not unlikely that the latter is its most efficient, perhaps indeed its only efficient, action. The methods of dressing are referi-ed to in connection with the separate opera- tions. Beyond the precautions referred to, namely, attention to asepticity of instruments and of anything brought in contact with the eye, and the use of frecpient irrigation, nothing further is required in the way of antiseptics. Some few operators attach importance to operating in an aseptic, or su]:)posed aseptic, atmo- sphere. To do this they take the most elaborate precautions in the arrangement of their operating rooms, use a special dress for operating, etc. Such precautions, however useful they may be in larger operations, are unnecessary in the case of eye opera- tions. It is not possible in this way to get any further reduc- tion in the number of inoculations than by a conscientious attention to the simple precautions against the real sources of danger, namely, the introduction of septic matter by the hands, lotions, or instruments, and the self-inoculation which may take place fi'om the secretions of the conjunctiva and tear sac. In performing any operation, the operator's fingers should never be brought into direct contact with the eye. The speculum and fixation forceps render this unnecessary, and these instruments are easily made aseptic, whereas the fingers may, even with the best pi'ecautions, convey infectious matter. CHAPTER II. EXAMINATION OF THE EYE. A SYSTEMATIC examination of the eye should be both subjective and objective. In the subjective examination the patient is first (questioned as to any abnormal sensations which he may experi- ence. Suitable tests are then applied in order to determine the degree of perfection Avith which the various visual functions are performed. By the ohjective examination a more complete explanation may be found of the cause of any abnormalities which are re- vealed by subjective tests. Considerable experience is sometimes required to know how far the result of subjective examination is in accordance with, and can be explained by, what may be found objectively. Both objective and subjective examinations should be made in a routine manner. This prevents any existing defects or abnormalities from being overlooked. On the whole it is advisable to complete the subjective, before i^roceeding to the objective, examination. But there are certain preliminary points in an objective examination to which attention should first be given. For instance, an inspection may first be rapidly made of the lids, conjunctiva, cornea, and iris. Then the state of the intra-ocular tension and of muscular equilibrium may be noted before the subjective examination is begun. After the visual acuity of each eye has been detei'mined, and any other subjective test which may be considered necessary applied, the objective examination may be continued in the dark room, first by examining the cornea, iris, and anterior surface of the lens by oblique illumination, then by refiecting light with the ophthalmoscope into the eye to ascertain the transparency of the other dioptric media, and finally by obtaining an ophthal- moscopic image of the different parts of the back of the eye. INSPECTION. Preliminary Objective Examination. By insjiection of the lids we note any abnormality of the skin and of the cilia, also whether the puncta lachrymalia are rightly applied to the eye, or at all everted. The position of the lids with respect to the eyes should be noted. By causing the patient to move the eyes upwards and downwards, any abnor- mality in the lid movements may be detected. By placing the finger or thumb on the skin of the lower lid and slightly pulling it down, while the patient is directed to look up, the lower lid is everted, and the conjunctival surface brought into view. If this be normal in appearance, it is generally unnecessary to ex- amine the inner surface of the upper lid, but should the lower be injected or inflamed, or should there be any affection of the cornea or history of any foreign body having struck the eye, the upper lid must also be everted. This is done by raising the lid with the thumb of the one hand applied to its outer surface, so as to cause the eyelashes to project forwards. The eyelashes are then grasped between the forefinger and thumb of the other hand, and the lid in this way pulled downwards and forwards, while the patient is told to look down. At the same time the skin below the first thumb, which is slightly raised from its former position, is pressed downwards. Finally, a movement of rotation upwards of the other holding the margin of the lid, is made round it as a fulcrum. This causes the conjunctival sur- face to spring into view, and the more completely the more the eye is directed downwards. A more thorough exposure of the whole of the retro-tarsal fold of the conjunctiva is sometimes necessary. This may be got by pressing down the upper part of the skin of the lid with a probe, whilst the lid is kept everted in the manner described. Attention should also be paid to the condition of the tear mc, over which pressure may be made in order to see whether or not this causes any regurgitation to take place into the eye. The importance of this is explained in the chapter on diseases of the lachrymal apparatus. Ins23ection of tJie cornea may be rendered difficult by the more or less convulsive closure of the lids. Under such circumstances the eye should be opened with the finger tips applied to the lid margins ; or Desmarres' elevators (Fig. 3) may be used. This is advisable, e.g., if there is danger of bursting an ulcerated cornea. One elevator is inserted carefully under each lid and the eye opened by drawing them apart, avoiding at the same time any pressure on the cornea. 10 EXAMINATION OF THE EYE. When the i)atient is placed facing a window, any irregularity of the cornea is readily seen by the distorted image of the window reflected from the defective portion of the corneal sur- face. To observe this the patient is made to follow the ex- aminer's finger as it is moved in different directions. By means of a specially constructed corneal microscoj^ pathological changes in the cornea may be examined under a magnification of from ten to thirty diameters. The intra-ocidar tension may be tested by gently pressing the tips of the two forefingers on the eye through the upper lid, while the patient looks down. By alternately varying the degree of pressure of first the one and then the other on the eye, some idea is obtained of the resistance which it offers. Another way is to cause the i)atient to look up, and a})ply the tip of the forefinger of one hand directly to the conjunctiva of the globe below the cornea, making a slight tapping movement without altogether removing the finger from the eye. The significance 3. — Desniarres' retractor. of the impressions thus conveyed to the finger is referred to in the chapter on glaucoma. The condition of the external muscles of the eye is determined, as far as is necessary for practical purposes, by causing the patient to fix a distant object alternately with either eye, whilst the observer's hand is held in front of the other, and by noticing whether any movement takes place, on removal of the hand, in the eye which has been occluded. If the eye be then moved inwards, there must have been a divergence, if outwards a convergence, of the axes when it was excluded from fixation. Convergence is tested by causing the patient to fix a small object, which is gradually approached to his face, and then noticing the shortest distance up to which the two axes continue to be directed towards it. Subjective Examinations. Visual acuity. — One of the most important points to deter- mine in all cases, and one which, whatever be the complaint of ACUTENESS OF VISION. 11 the patient, should be tested as a matter of routine, is the degree of his visual acuity. This should be tested for each eye separ- ately. The visual acuity is inversely proportional to the smallest visual angle under which two objects still give rise to distinct, separate, impressions. As the degree of absolute illumination is of influence on the acuity of vision, the ordinary test for the form sense should be made under a good illumination, such as is afforded by ordinary daylight or the light from a good gas burner placed close to, and reflected on to, the object serving as a test. It has been found by experiment that two black objects on a white ground, if propei'ly illuminated, can be seen by the normal eye as discrete when separated by a space which subtends an angle of 1' with the eye. That is to say, if the visual angle (Fig. 4, A or B) is equal to 1'. This limit, though not in all cases the very lowest, is a suitable practical basis for the con- Fk;. 4. — Diagram of visual angle. struction of a scale of visual acuities. When the eye is capable of this degree of discriminating power, it is considered to have full visual acuity. If the smallest angle be, on the contrary, 2', 3', 4', the visual acuity is correspondingly expressed by the fractions ^, J, and \. Various test objects, prepared according to the princi})le just explained, are in use for the practical determination of the acuteness of vision. That most commonly used is the set of test types known as Snellen's test types. These consist of a number of letters of the alphabet, or other figures, painted black on a white background. They are so formed that their height and breadth subtend angles of 5', while the spaces separating those portions, which must be seen as discrete parts in order that the shape of the figure may be recognised, subtend angles of 1' at the distances at which they should be read by anyone possessing normal visual acuity. A series of such letters or figures arranged in lines, the 12 EXA^IINATIOX OF THE EYE. letters in each line being the same size, while there is a differ- ence in the size of those in consecutive lines, constitute the set of test types. Above each line is placed a number, which indicates in feet or metres the distance at which the letters should be read. The number of lines usually employed is seven. Of these the one containing the smallest letters ought to be recognised at 20 feet, and the others should with the same visual acuity be recognisable at 30, 40, 50, 70, 100, and 200 feet respectively. Other tables have the distances marked in metres, the smallest letters being recognisable at 6 metres, and the others at 9, 12, 18, 24, 36, and 60 metres i-espectively. The smallest letters are taken, therefore, of such a size that it is possible to place a patient at a distance from them which can be conveniently obtained in most consulting rooms. Where the room is considerably less than 20 ft., or 6 metres, in length, an additional line containing letters recognisable at 15 ft. may be added. With the aid of Snellen's test types the degree of visual acuity can, with sufficient accuracy, be expressed as a fraction, the denominator of which is the number giving either in feet or metres the distance at w^hich the smallest type legible by the patient ought to be read, and the numerator that which on the same scale indicates the distance at which the individual tested is placed from the test. Thus, if at 20 ft. distance the line marked 70, and which should therefore be recognised at 70 ft., can only just be made out, the acuity of vision ( Visus or V) is f ^. If the patient has to apjiroach 3 ft. nearer before being able to read that same line, V = i^, and so on. When none of the types are seen at 20 ft., — that is, when (as the largest should be seen at 200 ft.) the vision is less than th^tj — the fraction expressing it may be found by approaching nearer and nearer to the types. If, for instance, the largest tyj^e, and that alone, were first recognisable at 5 ft., the acuity of vision in such a case would be represented by tt^. In cases where the vision is very bad, it is customary to note the distance at which the outstretched fingers can be counted against the dark background of the examiner's coat, the result being noted as follows: V = fingers at 3 ft. or at 8 ft, as the case may be. When the vision is so far reduced that fingers cannot be counted even when close up to the eye, but yet the' move- ments of the hand perceived, Y is said to equal movements of the hand. This is often denoted thus : V = hand-reflex. When even this degree of acuity is not present, there may still be per- ception of light, or V = perception of light (or V = P.L.). LIGHT SENSE. 13 The main object in making the test of visual acuity is to ascertain the degree of acuteness of vision in any particular case at ditterent times, either in the course of any disease, or with and without optical correction. This is for practical purposes sufficiently, accurately, and most rapidly determined by Snellen's test types, which have attained a popularity very much greater than other similar, and in most cases less accurate, tests. The average visual acuity of the normal eye diminishes with age. This is shown diagrammatically in Fig. 5. Besides the acuity of vision, or the acuity of the sense of form, two other functions of the central portion of the retina sometimes call for investigation, namely, the colour vision and the sense of light, independently of form and colour. kO 50 60 W 80 ^/ ^6 "^ ^ \ ^e Fig. 5,- -Curve of average visual acuity at different ages in the case of healtliy eyes. — After Boerma. The method of testing the central colour vision is discussed in Chapter XVI. Light sense. — When an examination of the light sense is made, it is necessary to gain information with respect to two different points— (1) The amount of illumination which is just sufficient to give rise to a sensation of light ; and (2) the smallest differ- ence between two intensities of illumination which is capable of being distinguished. It is difficult to make the examination in such a way as to clearly discriminate between pure sensations of light and mixed sensations of light and form. But in the examination of the light sense, as in all other subjective ex- aminations, whatever their nature, our object is not to get mathematically accurate results, as that is impossible, but only U EXAMINATION OF THE EYE. suc-h for wliicli the limits of error are not too wide for practical purposes. A (liHiculty in connection with all methods for determining the mininmm perceptible (jiumtity of light (the Uijht minimum) arises from the enormous degree to which that ijuantity varies, according to what is known as the state of adaptation of the retina. The sensitiveness to light is many hundred times less when the eye has Vjeen expo.sed for some time to strong day- light, than it is when it has been for some time (twenty minutes or longer) entirely kept in the dark. Practically, then, the unit must often be taken from a comparison with one's own light j)erception under the same conditions, and with proper care that the patient examined understands the nature of the test which is being made. Marked increase in the light minimum is jiatho- gnomonic of changes in the percij)ieut elements of the retina, more i)articularly the hexagonal i)igment cells. Marked diminution in light diti'erence [lerception characterises changes in the nerve elements of the retina and their central connections. It is sutKcient for practical purposes to recognise the abnormal manner in which the form sense is influenced by the conditions of illumination. It is a matter of experience that where the minimum perceptible degree of illumination is very appreciably greater than normal, a marked diminution in the visual acuity is found under an illumination which either does not at all affect, or it may be only slightly affects, the acuity of the normal eye. It is evident, too, that an eye which is very deficient in its appreciation of differences of intensity of illumination will be influenced in its visual acuity for objects the se])arate and dis- tinguishable parts of which are not strongly contrasted in their relative luminosity. One of the simplest practical methods, then, of testing the first element of the light sense is to diminish the illumination until it just begins to affect the acuity of one's own (presumably normal) eye. An equally practical test for the second element exists in Bjerrum's test types, which consist of Snellen's types i)rinted grey on grey. The contrast between the letters and the background is much less than for the ordinary types, which are printed l)lack on white. The vision of the j'^'i'tpheral portions of the retina may be defective with resitect to all or any of the senses of form, colour, and light. As the nature ui such defects often throws light on the diagnosis and prognosis of a case, the testing of the peri- pheral retinal functions takes an important place in the sub- jective examination of the eye. PERIPHERAL VISION. 15 Peripheral vision may be defective in continuity or in acuity. Often there is a defect in both respects at the same time, that is to say, that the most peripheral portions, where the normal acuity is least, may have their acuity reduced to 0, while the same cause of impairment reduces, but does not altogether abolish, the acuity of the more central portions. But besides regular interruptions in the continuity of the field of vision, which manifest themselves by some limitation, in the normal extent of the field in some particular direction, or in all direc- tions, irregular breaches in continuity, or more or less blind Fig. 6. — Diagram .showing horizontal extent of field of vision. portions surrounded by normal or relatively normal portions of the field, are met with, to which the name of scotomata has been given. To make an accurate examination of the field of vision it is necessary to make use of some sort of ijerimeter. Such an examination takes some little time, and is only called for in certain cases. A rough examination, which is usually sufficient for the determination of any existing limitation in the peripheral boundaries of the field, should be made as much a matter of routine as the taking of the central visual acuity. It may be IG EXAMINATION OF THE EYE. made in the following manner. The patient is placed with his l)ack to the light, and facing the observer. He is directed to cover one eye with his hand, and to fi.x steadily with the other the eye of the observer, which is directly ojiposite his own. Therefore, if the left be the one to be examined, the patient fixes with his left eye the right eye of the observer, whilst the observer at the same time fixes with his right eye the patient's left. In this position there is obviously a plane at right angles to the common line of fixation, and cutting that line at its mid- point, any point on which, provided rays from it enter the two eyes, will have an image at correspondingly situated points on the two retime. If, therefore, the observer, on moving his hand in any direction in this plane from or towards the middle of the line of fixation, finds that it disappears from or comes into his own and the patient's view simultaneously, it follows that their fields of vision are coextensive in that direction. A test in this manner can be rapidly made in all directions, and a want of coincidence of the two fields in any or all directions be easily discovered. This method of testing is only, however, a qualita- tive one in so far as by it the existence, and not the extent, of a limitation is determined. For the purpose of obtaining more accurate measurements of the position and extent of any deviations from the normal character of the field of vision, as well as of estimating the peripheral visual acuity, a perimeter is requii'ed (Fig. 7). The result of a perimeter examination is most conveniently recorded on a chart, which consists of a number of concentric circles, the radii of which increase by an equal amount, and a number of radiating lines from their common centre. The circles, of w^hich there are usually nine, rej)resent at intervals of 10° the angular aperture of the field ; the lines the diffei'ent meridians. In the charts commonly used, the centre of the figure, therefore, corre- sponds to the i)oint of fixation, whilst the concentric circles represent the i)ortions of the field whose retinal images are equi- distant in all directions from the fovea. If there be any doubt as to the restriction of the field in any particular case, the examination is best made in a subdued light, the intensity of which is a little greater than that which begins to tell on the normal field. This is a sort of conq)romi.se between the exami- nation of the light and form senses which is of considerable practical importance. The normal extent of the field of vision is subject to variation at its iqjper and also (though to a less extent) at its inner part, owing to individual peculiarities in the size and shape of the PERIMETER. 17 eyebrows and nose. The physiological limits may be taken to be as follows : — Upwards, 45° ; upwards and outwards, 50' to 55° ; outwards, 90° (often slightly more) ; outAvards and down- wards, 80° to 85° ; downwards, 70° ; downwards and inwards, 60° (variable on account of the nose) ; inwards, 55' to 60° ; inwards and upwards, 55°. The extent of the field upwards, Fig. 7. — Self-registering perimeter. — M 'Hardy. and upwards and inwards, is found to be 5° to 15° greater when the point of fixation is situated 20° or 30° from the centre of the perimeter in the opposite direction. This has to be borne in mind when there is a doubt as to whether or not there is limita- tion in this region. Thus, should the exploration with the centre of the perimeter as point of fixation only give an angular 18 EXAMINATION OF THE EYE. dimension of 40" for the peripheral extension of the field upwards, we should not always bo right in. assuming a contraction in this direction, uidess no increased measurement resulted from testing with a lower point of fixation. The maximum extent of the field of vision is only got for objects .seen under a visual angle of Y ^""^ more. For smaller visual anix!ar to be slight conoentric limitations got from an examination by the small visual angk' method. It is the irregular limitations, the more or less sector-shaped defects and blind areas (scotomata), which are of the greatest im])ortance. Concentric limitations are met with by this test as individual peculiarities. Tender normal con- tlitious, however, there are never found to be marked indentions or scotomata in the tliminished tield. Variations in illumina- tion, it must be remembered, too, have a somewhat greater influence on the results got by testing with the small images than in the case of the oi-dinary perimetric method. The eftect of tiring is also more noticeable than in tests made with the ordinary jierimeter. The most trustworthy test for peripheral visual acuity is that made with small objects at a distance by Bjerrum's screen test. The determination of the limits of the field for different colours, may be made with pieces of coloured j^aper. The results thus obtained are influenced by the hue and shade of the colour used, by the size of the coloured objects, and by the quality and intensity of the light under which the exanunation is conducted. Practically, in examining any case it is useful to determine the extent of one's own visual tield in one or two directions under the same conditions, and then allow something for individual j^culiarity besides. Another ])recaution that will be found useful is to have the test object (which it is well to make 20 mm. square) differently coloured on either side. In this way we are provided with a check on the accuracy of the patient's state- ments. The most convenient colour to use is some hue of red, as it is for the reds and greens that pathological defects in the colour sense first manifest themselves. When the red-green per- ception is entirely abolished, the limits may be taken for blue or yellow, the vision for which is almost always longer in dis- appearing; but the main necessity for this is to exclude the possibility of the more usual form of congenital colour blindness, which we should have reason to suspect if the peripheral boundaries for yellow and blue were not restricted. Subjective Sensations. The different subjective sensations which may be complained of, and for which a projjcr objective examination will afford a more or less satisfactory explanation in most cases, need only be shortly referred to in this chapter, as they are mentioned in connection with the diseases in which they are mostly mani- PAIN. 21 fested. The principal ones are pain, double vision, distorted vision, the appearance of spots or clouds in front of the eye, and subjective light and colour sensations. Pain. — Pain complained of in the eye may be non-inflam- matory. It may also be primarily due to inflammation of the eye or the surrounding parts. In a large })roportion of the cases of pain unaccompanied by inflammation, the pain only comes on, or is at all severe, when the eyes are used for work near at hand, such as reading or sewing. In other cases, again, the pain is independent of the use of the eyes. The name which is generally given to the non- inflammatory pain associated with the use of the eyes is asthenopia, which literally means a want of power in the eye to jjerform its functions, and therefore an inability to sustain an effort which under ordinary conditions would not be appreciable. Pain in the eyes, often described as at the back of the eyes, unconnected with any accommodative or muscular abnormality, and coming on, often very severely, at longer or shorter intervals after use of the eyes for reading, etc., is extremely common. Often the condition is associated with more or less sensitiveness to light. In many, and indeed most, of these cases there is absolutely nothing to be found, in connection with the eyes at anyrate, to account for the jjersistence or severity of the symp- toms. Either the strain on the attention becomes soon too over- l)Owering, or the retina itself is over-sensitive and easily tired. Some weakness exists in the tone or capabilities of the nervous mechanism of vision. Such a state of nervo^is asthenojna is prob- ably frequently of reflex origin, though the region from which the aff"erent stimulus proceeds is not often apparent. Many cases of retinal or nervous asthenopia are amongst the most severe and rebellious that one is called upon to treat. Cold water douches, and iron internally, are indicated in some cases ; others are much benefited by hot sponging or fomenta- tions ; and where there is absolutely nothing abnormal to be discovered in the eyes, an energetic attempt should be made to break the habit of giving u]) reading as soon as the pain comes on. This can only be done gradually, but is successful in many cases. Pain, independent of the use of the eyes, is often complained of, and is generally of a neuralgic character, and more or less intense. The diagnosis is easily made when there are 23oints of special tenderness around the eye. Occasionally, no doubt, the pain is reflex, but the origin of most cases is an over-sensitiveness of the supra- and infra-orbital branches of the fifth nerve, gener- ally caused originally by exposure to cold. 22 EXAMINATION OF THE EYE. When the pain is due to inHauiniation, the diagnosis is often aided by noting tlie circumstances under which it is most intense. Thus sometimes it comes on mostly at night, at other times mostly when light falls into the eye, or when the eye is moved in some particular direction, or by pressure on some parts of the eye itself, or of the surrounding structures. Diplopia. — When double vision is complained of, we have, in the lirst jilace, to determine, by covering first the one eye and then the other, whether in either case it is still present, or whether it always disapi>ears when one eye alone is used; that is to say, whether the diplo2)ia is uniocular or binocular. If tliere is a fair amount of vision in both eyes, and no abnormal degree of mental suppression of the image falling on the mis- directed eye, there will usually be binocular diplopia when both axes are not simultaneously directed on the same point of the object which engages the attention. There may be no diplopia complained of even though there be wide divergence of the visual axes, owing to the unconscious mental suppression of the image of the one eye when the other is used for fixation. This sup- l»re8siou is sometimes so complete, that under no circumstances can the diplopia be made apparent. In other cases, by holding a red glass or a prism with tlie angle directed upwards or down- wards in front of the fixing eye, the faulty image of the other is at once seen, showing that the suppression is only effected for normal conditions of similarity in the optical images or only for a retinal area, on which, under ordinary circumstances, the images corresi)onding to tho.se occupying the centre of the retina of the fixing eye are received. Again, an individual may complain of diplopia even although the visual axes are capable of crossing, and actually do cross, on the same object. This is the case when other objects than the one fixed engage the attention, and is, in fact, physiological, in so far as most olyects not directly looked at are seen double. When, therefore, this kind of double vision is complained of, it is owing to an abnormal degree of attention being directed to objects other than those fixed. Usually tliere is a suppression of one of the images of other objects than the one on which the visual axes are directed — a su])pression which i.s often so com- plete as to render it ditticult for many peoi)le to become con- scious of this jihysiological diplopia. Which eye is the one whose images are suppressed in any jtarticular case may be determined by a very simple experiment. By asking anyone, while keeping both eyes open, to hold up their finger in a line with some distant object, and then close first the DIPLOPIA. 23 one and then the other eye, they will generally hnd that the finger exactly covers the object as seen by one eye, while it deviates to one side when looked at with the other. This shows that only the image formed in the eye, in a line with which and the distant object, the finger has been placed, is observed, that in the other being more or less completely suppressed. The cases of diplopia just referred to are due to the opposite condition, namely, to a too ready appreciation of the physiological double images. This is mostly met with in women, but occa- sionally also in men. When once discovered by them, and not recognised as physiological, they contract a habit of directing attention to the double images which sometimes becomes almost painful. Occasionally it is the nose which is in this way brought prominently before their notice, and which always appears to get in the way of other objects, by attracting attention at the same time ; at other times, any objects, both beyond and nearer than the point of fixation, are continually forcing their two images on the attention. The manner of testing for binocular diplopia, as well as the interpretation of the results thus obtained, is fully discussed in the chapter on muscular anomalies. When the diplopia complained of is found, in the way already described above, to be uniocular, the cause will generally be some error of refraction which has long existed or has been lately acquired, and a careful examination will be necessary to dis- cover it. We have first to find out whether the diplopia has suddenly made its appearance or not. If so, it may either be due to some trauma, or the conditions giving rise to it may have previously existed, and only be observed owing to some circum- stance which has caused the patient's attention to be directed to it. If there has been a trauma, we may look for irregular astigmatism, or some refractive changes, due to alteration in the position or condition of the lens, etc. The most common causes of acquired uniocular diplopia are changes sometimes occui'ring in the lens during the formation of cataract, and alteration of the curvature of the cornea i)roduced by inttammatory changes. When not due to a trauma, the doubling of the image in one eye, hitherto existing, though unobserved, may sometimes sud- denly force itself on the attention, either owing to increased retinal susceptibility to impressions, or to some cause having temporarily disabled the other eye ; and when once discovered it may become more or less troublesome. In this way we some- times find uniocular existing along with ]"»inocular dijilopia, the 24 EXAMINATION OF THE EYE. former being first l)rought to notice by the occurrence of the hitter. Metamorphopsia. — Wlien flistorted vision, or metaniorphopsia, is cumphiiued of, it .shouhl suggest either some cause altering the character of the impressions formed on the retina, as, for in- stance, irreguhir astigmatism, or some pathological change which interferes with the normal manner in which our judgment of the shaiKJ of objects seen is formed. The apparent shape of objects dej lends, in the first place, on the configuration of their i-etinal images ; it is therefore more in accordance with their actual shape the more regular is the refraction of the rays through the dioi)tric media of the eye, and the more accurately the rays are focussed on the retina. For the correct appreciation of form it is further necessary that the perci})ient elements of the retina should be grouped according to their normal arrangement in the focal surface of the eye, and should all be capable of excitation to some extent at lea.st. Of the size of objects, again, we judge partly from the size of their retinal images, but as this, besides depending on the actual size of the objects, depends also on their distance from the eyes, the appreciation of size is more correct the more accurately the distance is gauged. In comjiaring the sizes of two or more objects, we are probably guided by the appreciation of their retinal images alone, if they are small. When of any consider- able size, however, the method of comparison is more complicated, and depends chiefly upon the knowledge gained by the sense of mu.scular innervation on running the eyes along over the different points of the objects. Defects of accommodation give rise to alterations in apparent size, owing to the error in the judgment of the distance of objects (within the ordinary range of accommodation) which results from them. Thus, where all at once there is a paresis of accommodation, and a greater effort has to be made in order to focus a near object distinctly, or to attem}»t to focus it distinctly, this gives rise to an impression of greater proximity of the object, and as the image on the retina is of course the same size as it would be were its distance more correctly estimated, it appears smaller. The micropsia thus occasioned is often very marked, and is met Avith both in cases where the paresis is the result of a direct, and where it is due to a reflex, interference with the functions of the branches of the third nerve which supply the ciliary muscle. The jiaresis may occur idiopathically, or be due to the action of a mydriatic. Conversely, a spasm of accommo- dation, from whatever cause, sometimes gives rise to macro2)sia, SCOTOMATA. 25 as the consciousness of an abnormally feeble effort to accommo- date the eye for a near object causes the object to appear more distant, and therefore bigger than it would be otherwise estimated. Macropsia has been observed after the use of such miotics as pilocarpine and eserine. Accommodative micropsia is most marked the nearer the object lies to the eye ; accommodative macropsia, on the other hand, the farther it is removed from the eye. But, besides metamorphopsia due to defects in accommodation, there are also similar misjudgments as to size, caused by abnor- mally impeded or facilitated movements of convergence of the optic axes, or by any optical conditions which permit of binocular fixation with the axes of vision directed so as to meet either nearer or farther off than the object looked at. Thus, prisms with the bases inwards in front of each eye appear to magnify, owing to the axes of vision meeting farther off than the objects looked at. Prisms with the bases outwards in front of each eye appear, on the other hand, to diminish, as under these circum- stances the axes of vision cross in front of the objects fixed, which appear nearer and consequently smaller than would be the case without the prisms. Operations on the muscles of the eye are sometimes, if there has been previously binocular vision, followed by similar apparent alteration in the size of near objects. Metamorphopsia due to alterations in the percipient elements of the retina, brought about by choroidal exudation, is described in the chapter on diseases of the choroid. Scotomata and clouded vision. — When a patient complains of seeing a spot or spots in front of the eye, we have first to inquire whether the appearance is stationary and constant, or is only seen when the eye is suddenly moved, or has an independent motion. Its behaviour in these respects gives a clue where to look for the cause. When stationary and always projected in the same direction with reference to that taken up by the eye, it will either be due to some circumscribed opacity of the cornea or lens, possibly also of the vitreous, or to some change in the retina. An interruption in the field of vision of this last nature is called a 2Msitive scotoma. When there is no consciousness of an interruption corresponding to the more or less blind area, the scotoma is said to be negative. Where a lesion primarily involves the nei've fibres of the retina the resulting scotoma is unperceived or negative ; where, on the other hand, lesions involving the retinal pigment and choroid cause the scotoma, there is more or less consciousness of its existence. The shape of a positive scotoma may often be 26 EXAMINATION OF THE EYE. learnt by ivsking the patient to draw the outline of it on a piece of white pajier. Positive scotomata are generally most marked in subdued light. Where the spot is not stationary it is generally due to the shadow cast by something in the vitreous. Small s})ots, or luusccr^ volifantes, which cannot be detected with the o})hthalmoscopc, are very commonly complained of. Clouded vision is often met with, and should direct attention to the choroid or to the possible existence of glaucoma. If intermittent in its character, there will often be reason to suspect glaucoma. Patients suffering from glaucoma often complain of .seeing everything clouded even when they are found on examina- tion to have full visual acuity. Sensations of light and colour. — These may ari.se without there being any o])jective cause to account for them — that is, when no undulations of the ether, such as are cai:)able of giving rise to luminous impressions, find their way to the retina. A purely subjective sensation of this kind may be the result of a mechanical or chemical stimulation of the nerve fibres of the retina or optic nerve, or of the centres of vision. The light so seen may appear coloured or uncoloured, according to the site and nature of the stimulation. Direct pressure over a portion of the eye behind its equator produces in the dark a so-called 2)hosphene or sensation of light, which is referred to the opposite side of the field of vision. A common cause of coloured vision, owing to a change pro- duced on the compound rays of white light as they enter the eye, is afforded by those states of the cornea which give ri.se to diffraction. In looking at the street lamps, for instance, through the glass of a carriage window, which is covered mth the closely I)acked particles of moisture which arise from the condensation on it of the vapour within, one frequently notices the liglits surrounded by coloured haloes. The same appearance may sometimes be observed without the intervention of the glass, and it is then usually pathological and due to a similar arrange- ment of intransparent particles in the cornea. This symptom of seeing haloes round lights is one of the commonest and most important indications of the early stage of glaucoma. Although a frequent .symptom in glaucoma, such coloured haloes are by no means pathognomonic of that disease. They may be seen in all cases where the cornea assumes from any cause a diffuse cloudiness. Even the secretion which in some cases of con- junctivitis gathers across the cornea may give rise to them. When spontaneously complained of, and especially when there is no appearance in the cornea at the time of examination to OBLIQUE ILLUMINATION. 27 account for the halo, and when, too, it does not disappear on rubbing the eyes, its existence is strongly suggestive of glaucoma. Test for the presence of binocular vision. — It is sometimes necessary to determine whether in any case binocular vision exists or not. In this test, as made by Hering's method, the patient is caused to look with both eyes thi-ough a tube blackened inside, and across one end of which a string is stretched. If a small object, such as a bead or pea, be dropped immediately in front of or behind the thread, anyone with binocular vision can at once tell whether it has fallen nearer to his eyes or farther away from them than the thread. If binocular vision be absent, a few trials show that the relative distances of the falling object and thread cannot be appreciated. Further Objective Examination. The examination of the eye by obliaue focal illumination is of the utmost importance, and should always be undei'taken before making an oi^hthalmoscopic examination. It is done in the following way. The rays from the source of light used for ophthalmoscopic examinations are concentrated by means of a convex lens on the cornea. By slight movements of the lens the focus of light is made to fall on different parts of the cornea, and thus show up any imperfection. By its means any cicatrix, how- ever faint, can be detected. By approaching the lens slightly to the eye the surface of the iris may be brilliantly illuminated, and more thoroughly examined than l3y mere inspection without the concentrated light. Oblique examination may be combined with some method of magnification. A rectangular portion of a large lens is very suitable for this purpose, as it admits of the structures being seen binocularly. A better idea is thus got of their relative depths. For the more minute examination of corneal affections it is customary to use a strong convex glass placed behind the ophthalmoscope, or a corneal microscope. The action of the 2)upil, and the degree to which it contracts to light, may be tested by reflecting light on the eye by means of the ophthalmoscope mirror. In this way the light can be flashed on and off with a very slight movement of the hand holding the mirror. Its intensity can be altered by altering the distance of the mirror from the eye, or the strength of the source of illumination, which can readily be done if a gas jet be used. By keeping a constant degree of illumination on the eyes, and directing the patient to keep flxing the finger, as it is 28 EXAMINATION OF THE EYE. ai)proacliccl gradually nearer and nearer to the face, the presence or absence of contraction of the pupils, which is normally associated with accommodation and the convergence of the visual axes, is tested. Even in cases where the patient ex- amined is blind, the presence of an association between con- vergence and jtupillary contraction may be tested by causing him to attemi:)t to look at his own linger as he brings it nearer and nearer to his eyes. This will cause him to converge, and if Fig. 10. — Binocular corneal microscope. — Czapski. there exists an associated pupillary contraction it will then be seen. Examination with the mirror alone. — The central aperture of the mirror is held in front of the observer's eye, while the mirror is given such a direction that the light is reflected into the eye to be examined. As a rule, all that is seen by the observer, whose eye is placed behind the mirror, when light is reflected into the patient's eye with the mirror held at some distance from it, is a yellowish-red reflection from the back of the eye. If there is any detail seen in the red area of reflected light, it indicates that the eye examined is out of focus. OPHTHALMOSCOPY. 29 On the other hand, if the red reflex is either not seen at all when the light has been properly directed into the eye, or is found to be much duller than under normal conditions, or if it is interrupted here and there by more or less dark spots, the indication thus afforded is, that there is a diffuse or circum- scribed opacity or opacities in one or more of the transparent media of the eye. If, on oblique examination, such opacity has not been found to exist in the cornea or lens, it may be inferred that it is in the vitreous. If the opacities have an independent movement, or are vi^hat is called " floating," they are at once recognised to be in the vitreous. If the opacity causing the interruption in the red reflex is stationary, it is observed to have no movement independent of the eye, although there is an apparent movement as the eye is moved, which is greater or less according to the position of the opacity. If it lies behind the centre of curvature of the cornea (or more correctly, the image of that point which lies very near the point itself), it appears to move in the opposite direction from the eye. If it occupies a position in front of the centre of curvature of the cornea, it appears to move in the same direction as the eye, while the nearer it is to that point the less does it appear to change its position. Floating opacities are most readily made out by causing the patient to move his eyes rapidly in different directions, and then to keep them steady. The objects thus come into view in the illuminated area. Opa- cities in the lens may be limited, and can often only be seen if the pupil be well dilated with a mydriatic. There are tivo methods of obtaining an image of the fundus of the eye with the ophthalmoscope, known as the indirect and direct methods of examination. The former is generally pre- ferable, and in most cases all that is required ; but when an examination by this method does not afford an explanation for an existing visual defect, or when it is desired to study more closely any pathological changes, the direct examination should be made in addition, as by it a much greater magnification is obtained. Special attention should be directed— (1) To the optic disc, and notice taken of its colour, the size and condition of the larger vessels which lie on it, and the state of the imme- diately surrounding parts ; (2) to the periphery of the fundus, by causing the patient to look up and down, to either side, and, if necessary, slightly moving one's position so as to bring the most peripheral portions into view ; and (3) to the macula lutea. The examination of the region of the macula lutea is often difficult. This is owing to the greater contraction of the pupil, 30 EXAMINATION OF THE EYE. wliicli takes place when the light is concentrated on the macula. In addition there is a disturbing effect , produced by light re- flected from the cornea. It is generally best not to ask the j)atient to look directly at the oi)hthalmoscope, but slightly to one side, and then by slowly moving one's head bring the macula into sight. In this way a view of it is often more easily ob- tained. Often, however, it is impossible to get a satisfactory view of the macula without dilating the jjujiil. When the appearance met with at other parts of the fundus is not sufficient to account for the symptoms, there should be no hesitation about using a mydriatic in order to be able to explore the macula properly. The best mydriatic for the purpose is homatropiue, as it does not produce such a prolonged paralysis of accommodation as atropine, though it has the disadvantage of acting considerably more slowly. It is also safer in the case of old people, in whom, if there is a tendency to glaucoma, an acute attack of that disease is more likely to be set up by atropine than by the weaker mydriatic. The effect of homatropiue may be hastened by combining it with cocaine. By the indirect method of examination, a magnified inverted image is obtained of the structures at the back of the eye. The observer, placing the back of the ophthalmoscope mirror in front of his eye in such a manner that he looks through the aperture in its centre, reflects the light from a lamp or gas jet, at the side of the jiatient's head, into the patient's eye, and from a distance of 12 to 18 in: With the other hand he holds a convex lens, of a strength of from 10 to 15 dioptres, in such a manner that its centre comes to lie in a line joining the patient's pupil with his own pupil, and at a distance from the patient's eye about equal to the focus of the lens. The same lens should always be used in making examinations, so as to give a uniform idea of the relative sizes of the different pictures obtained. To steady the lens in this position, it is customary to rest the little finger against the patient's forehead. There is thus formed, between the convex lens and the observer, an inverted aerial image of some part of the back of the eye, which the observer can see if his eye is properly accommodated for the distance. By moving the head back and forwards, the IX)sition in which the image can be most distinctly seen is soon found. It will be farther away the greater is the distance of the observer's near point. Hypermetropes and presbyopes gener- ally aid their accommodation by liringing a small convex lens behind the a^terture of the ophthalmoscope. OPHTHALMOSCOPY. 31 By the direct examination a magnified erect image of the back of the eye is obtained. The observer, keeping his eye behind the aperture in the ophthalmoscope, reflects the light into the patient's eye from a distance of less than two inches, and receives the rays which pass back from the patient's eye into his own, and, focussing them on his retina, obtains an image of the structure from which they have been reflected. If the observer be emmetropic, and the patient emmetropic and un- accommodated, the image is obtained by the eye without any accommodation. If, on the other hand, the patient's eye be hypermetropic, the observer will have to exert a proportionate amount of accommodation, or place a convex lens sufficient to correct the hypermetropia behind the aperture in the ophthal- moscope in order to obtain a clear image of the fundus. If the patient or the observer be myopic, the latter will only obtain a proper definition of the image of the fundus by making the examination through a concave lens of suflacient strength placed behind the ophthalmoscope. It follows, too, that if the observer be myopic, and the patient hypermetropic, or vice versd, no lens or accommodative effort will be required, if the amount of the defects neutralise each other ; while, if they do not, the glass or accommodative change corresponding to the difference in the degree of ametropia is required to obtain a distinct image. This is more fully explained in the chapter on refraction, and cannot be properly understood uiiless the reader has some knowledge of the errors of refraction commonly met with. Both with regard to iUiimination and magnification, the fundus of the eye is seen in a very different manner from any other 23art of the body. It is this which in great measure causes the difficulty of interpreting what one sees. It is cus- tomary to make use of the optic disc as a convenient measure with which to compare the size of any change seen, or to gauge the distance separating such changes from each other, or from any point (often conveniently the disc itself). Thus we might talk of some haemorrhage or other spot in the retina being about half the diameter of the disc in size, and situated rather more than two diameters of the disc below it. The relative depth of the different parts of the back of the eye, seen with the ophthalmoscope, can be estimated with tolerable accuracy by noting the number of the lens which the unaccommodated eye requires to obtain a clear definition, and allowing roughly 3 dioptres to 1 mm. By the indirect examina- tion, differences in depth are rendered apparent by the parallactic displacement which Hakes place when the convex lens is given 32 EXAMINATION OF THE EYE. a slight moveincnt from skle to side. The structures lying nearer to the eye then a]){»ear to glide over the deeper-lying parts as their image moves more rapidly in the same direction as the len.s. Normal Fundus Oculi as sken avith the Ophthalmoscope. A great variety of different ophthalmoscopic pictures are presented by altogether normal states of the back of the eye. Indeed, the art of ophthalmoscopy consists quite as much in recognising the physiological varieties met with, and in diag- nosing the healthy fundus, as in understanding the nature of any pathological changes which may be present. It is usually comparatively easy to recognise the different diseases of the fundus oculi, often very difhcult to feel sure that there are no pathological changes. The colour which the fundus presents, and the amount of detail which can be made out, besides, of course, depending to some extent on the illumination and magnification, vary accord- ing to the density of pigmentation in the hexagonal cells of the retina. The red colour comes from the blood in the vessels of the choroid, but is modified by the pigment in the retinal hexagonal cells. The degree of pigmentation, again, bears a pretty close relation to the pigmentation elsewhere, so that a different aj^pearance is usually presented by the eye of a very dark individual when compared with that of a light-haired one. In the two extremes, namely, the eye of the negro on the one hand, and of the albino on the other, the difference is very pronounced. Apart from the actual depth of colour, it is usual to find a want of absolute uniformity of colour. The three regions where one most frequently notices differences in this respect, are the periphery, the area immediately surrounding the disc, and the macula lutea. In the periphery there is often more or less absence of pigment, causing a lighter colouring and greater visibility of the retro-retinal structures. Round the disc, on the other hand, a lighter colouring is often observable, owing to light reflected from the nerve fibre layer. In the region of the macula again, where the pigmentation is greater, there is always an increased dei)th of colour. A certain regular unevenness in the colour of the fundus throughout, giving rise to a stippled appearance, is more or less recognisable in different cases by the magnification obtained on direct examination. NORMAL FUNDUS. 33 Ophthalmoscopic appearances of the retina in health. — The retina, with tlie exce[)tioii of its larger blood vessels, or moi'e correctly, of the blood column in the vessels, is so trans- parent that in most parts it is practically invisible. In some eyes there is to be seen, and particularly in the neighbourhood of tlie macula, a kind of dull sheen of reflected light from the Fig. 11.— Normal fundus oculi (erect ophthalmoscopic image surface of the retina. In many eyes, too, there is a more or less marked striation visible, stretching from the disc for some distance in all directions, but mostly upwards and downwards. This striation is due to the presence of the nerve fibres which spread over the retina, and which in this position form a thicker layer than elsewhere. The macula lutea, or yellow spot, is an area occupying the 3 34 EXAMINATION OF THE EYE. centre of the retina in the direct line of vision, its centre or fovea centralis beinj^ that portion in which the visual acuity is greatest, and on which, therefore, the images of objects directly " fixed " fall. The macula is recognised by its occupying a position to the outer side of the disc, its centre being about two diameters of the disc from the disc margin, by its being relatively devoid of visible blood vessels, and by its darker colour. Sometimes it is seen to be circumscribed by a bright glittering band or " halo " of reflected light. At the centre of this halo, which is more or less distinctly elongated in a horizontal direction, lies the fovea cenfrali.'<, a whitish, Fig. 12. — Slmwinir oplithulnins.'diiir uii)icaiaiiri' wliie-h may be IjreseiitLnl \>y tlie iioniial uiacnla lutea. pinkish-white, or straw-coloured spot, often presenting at the same time a very marked glitter. The horizontal diameter of the macula is generally distinctly greater than the diameter of the disc ; its vertical diameter, on the other hand, perhaps hardly as great as that of the disc. The deeper pigmentation is sometimes pretty sharply defined, but more often gradually fades off" into the colour of the surrounding fundus. The yellow colour of the macula is never seen, owing, no doubt, to the preponderance of yellow rays in the light used for examina- tion. The halo round the macula is mostly seen in children, and especially in deeply i)igmented retina^, and hypermetropic NORMAL FUNDUS. 35 eyes. The band of reflection producing it gi-adually fades off to both sides, sometimes sending indefinite streamers of reflec- tion beyond, particularly to the outer side, or that farthest from the disc. It is, however, usually pretty sharply defined along the edge lying nearest the fovea, where it borders the more deeply pigmented area. Often a complete halo is not seen, but only a sickle-shaped portion of it. The concavity of the sickle then appears, on indirect examination, turned towards the middle line, though this may depend to some extent on the position given to the convex lens. The reason why the ring is not seen in the same way on direct examination is partly because of the different direction of the illuminating rays, and partly because the illumination is feebler. With a short-focus concave mirror there may be more or less indication of it on direct examination in cases where it is marked in the inverted image. Often at other parts of the retina, too, in young individuals, reflections similar to, though less defined, than that round the macula, ai'e seen as bands of light beside and between the larger vessels. The appearance of these reflections is not unlike watered silk. It is most marked in hypermetropes, and most distinct if the pupil is not dilated. The vessels of the retina, which apjjear as darker lines on the reddish fundus, are seen to spring from the disc, or intra-ocular termination of the optic nerve. The arteries and veins are dis- tinguished from each other in three ways, namely — (1) By the diameter of the blood column, that is to say, by their apparent relative sizes ; (2) by their colour ; and (3) by the manner in which they reflect light. The column of blood in the arteries is narrower than that in the corresponding and accompanying veins. The colour of the arterial blood is lighter, and, lastly, a very broad band of light reddish reflection is seen running down the centre of the artery. A streak of light is seen on the veins as well. It diff'ers from that on the arteries in being whiter and much narrower. It cannot be traced so far along the course of the veins, and is often seen to be interrupted at places. The distinctness of the line is greater in both arteries and veins, the stronger the illumination of the fundus. •The larger the pupil, therefore, the more distinct does the appearance become. An enlargement of the pupil produces, besides, an increase in the breadth of the line on the veins, but does not lead to any similar alteration of that on the arteries. The light streak on the veins is caused by reflection from 36 EXAMINATION OF THE EYE. the convex surface of the blood column, the refractive index of which differs from that of the trau.sjiarent walls of the vessels. The broader line on the arteries is perhaps also caused by reflection from the blood corpuscles of the axial current. The arteries, besides being narrower, are more tortuous than the veins. Not unfrequently they are even seen to twist round the veins at places. This twisting of the arteries round the veins, as well as the sharp turning of the veins, which often takes place as they emerge from the central depression on the disc, gives rise to an alternate, visible, i)artial emptying and refilling of small portions of the larger trunks on the disc, synchronously with the heart's action. This, which is called venoua pulsafii))i, is a very common physiological ])henomenon, not to, be confounded with visible pulsation in the arteries, which is probably always pathological. The main trunks of the central artery and vein divide on the disc, or more frequently, some time before they come into view, into a superior and an inferior branch. The further division which takes ])lace is always dichotomous, the narrowing becom- ing gradually more and moi'e appreciable as the vessels pass to the periphery. The situation in which the main division of the vessels takes place on the disc, first into an upper and lower branch, and then each of these into a nasal and temporal portion, is subject to such great variety, that it is almost impossible to find two eyes with exactly the same arrangement in this respect. Even the number of vessels on the disc is not constant. The site at which the first division takes place may also produce some differences in the ophthalmoscopic appearance. Thus, when the artery or vein divides just on a level with the disc, having up to this point coursed in a direction parallel with the axis of the nerve, the appearances presented as one looks down, as it were, on the cross section of the main vessel, and therefore on a perpendicular column of blood, is that of a much darker spot at the point of division. Sometimes vessels are found to the outer side of the disc, which are seen to spring into view at its margin, between it and the edge of the choroidal ring. These vessels, in the first part of their visible course, are usually directed towards the disc. After making a more or less extensive curve, they pass into the retina. They appear sometimes to be offshoots of the central vessels which have passed out of the nerve before reach- ing the disc. They are more frequently, however, branches of the short posterior ciliary arteries, and have received the name of cilio-retinal vessels. NORMAL FUNDUS. 37 Ophthalmoscopic appearances of the optic nerve in health. -The Clitic di.sc, or the end or cross section, as it were, of the Fig. 13. — Normal di.iu.^, showiuL; ilillLiL-ut anaiiuenit-ut of v 38 EXAMINATION OF THE EYE. optic iiervo, tliat portion which is alone visible with the ophthal- moscope, receives its name from its circular shajie. Its real diameter varies in different individuals from 1 "5 to 1 "75 mm. There is often, too, a difference according to the direction in which the measurement is made. It is, in fact, rarely a very perfect circle, though, in the majority of cases, it is very approxi- mately circular. Considerable differences are met with : thns it may Ijc very decidedly elongated in one direction, most frequently obliquely, Init with the long axis nearer the vertical than the horizontal. It is sometimes flattened more or less at one or more parts. It is inq)ortant that the natural oval shape of the normal disc, in some cases, should not be confounded with the oval form seen, owing to purely optical conditions, where there is astigmatism. In order to convince ourselves that the oval form is that really presented by the intra-ocular end of the nerve, we have only to withdraw or approach the convex lens, and observe that no alteration of shape takes place. The disc is far from having a uniform colour, and the colour is one which is not very easily described. It is subject, besides, to considerable variation. This should be remembered, and great care exercised not to infer too readily that an appar- ently excessive degree, either of pallor or redness, is pathological. At first sight it is markedly pale or white as compared with the rest of the fundus. What gives the white appearance is the reflection of light from the lamina cribrosa, the altered sclerotic coat through which the nerve passes. But a closer inspection shows that the disc is not by any means colourless. It is of a rosy-pink colour, which at some parts appears as if mixed with grey, at others with blue, and through Avhich, one, as it were, sees the white light shining. The colour varies according to the degree of illumination, and is less uniform in a feeble or moderate illumination than in a very strong one. The differ- ences in colour, too, are most clearly seen on direct ophthal- moscoi)ic examination. The most markedly [)inkish portion is almost always a greater or less crescentic bit of the inner or nasal half of the disc, that portion which is farthest away from the macula. This part is often so decidedly coloured that it presents but a slight difference from the surrounding fundus when the illumination is not great. There is always, however, an api)reciable difference in hue. The pinkish colour of the disc is due to the reflection of light from the blood in the vessels which supply the intra-ocular end of the nerve ; and it is owing to the layer of nerve tissue NORMAL FUNDUS. 39 being thicker, and consequently occupied by a greater number of blood vessels to the inner side than elsewhere, that the colour there is deeper. Less light penetrates through to, and is reflected from, the underlying lamina cribrosa than in other parts, where there is a thinner layer of nerve fibres. The least coloured, and often decidedly, even intensely, white portion of the disc, is its centre. At this spot, owing to the separation of the nerve fibres in all directions, there is a little conical, funnel- shaped depression formed, at the bottom of which there is nothing but the lamina cribrosa, the light reflected from Avhich does not sufter any alteration before it meets the eye. The result is, therefore, that one sees a white circular spot in this situation, which sometimes, on direct examination, exhibits some indication of the structure of the lamina cribrosa. Often the white area is not circular, but, while very markedly w^hite, and contrasting strongly with the bordering coloured portion to the inner side of the disc, merges more slowdy into a deeper colour in other directions. Not unfrequently starting from this point, a sector-shaped area of the outer or temporal portion of the nerve is very devoid of any pinkish colour, and presents instead a mottled bluish- w^hite aspect. This mottled appearance is due to reflection of light from the lamina cribrosa, and the nerve bundles which pass through that fibrous meshwork. The strong dull white is caused by reflection direct from the fibrous tissue; the steel- coloured, bluish-white, more diaphanous appearance, on the other hand, is the result of repeated reflections from the pits or channels in the connective tissue through which the transparent nerve fibres pass. This appearance of the outer half of the disc, which is sometimes seen, appears to depend more on the absence of blood vessels, than on the absence of nerve fibres in that region, although they undoubtedly form there a shallower layer than in other parts. Occasionally masses of pigment, which rarely attain any size, are seen in the disc. These pigment spots are mostly formed near the margins. The margins of the disc are always sharply defined, though sometimes this definition is less marked above and below than elsewhere. The disc is usually seen to be surrounded by a white or slightly yellowish-white ring. This is what is called the "scleral ring." This ring varies considerably in breadth in different cases, but is most frequently very narrow, only just discernible on careful examination by the direct method. The scleral ring is formed, as its name implies, by a surrounding 40 EXAMINATION OF THE EYE. portion of the solera, the white colour being due to the strong rcHection from that coat. The opening in the choroid is always larger than that in the sclera, and hence it is possil)lc to see this portion of the sclera ; although, owing to the overhanging of the expanded intra-ocular end of the nerve, as well as to the frc(iuent heajting uj) of pigment at the margin of the oi)eniug in the choroid, the view of the sclera in this situation is often very nuich masked. The portion of the ring to the outer side of the disc is commoidy the most evident. It is in this direction too, mostly, that it is usual to find some ])igmcnt accumulated at the margin of the choroidal o})ening or " choroidal ring." Physiological excavation of the disc. — One of the most important and frequent variations from the typical condition of the disc, is that to which the name of physiological "cui)ping," or "excavation," of the disc is given. This variety in the con- formation of the intra-ocular end of the nerve is met with in very ditlerent degrees and in different forms. Altogether, some degree of cu})ping is about as freipient as the absence of any cu[)ping at all. Although they vary thus greatly, all physio- logical excavations have the following characteristics in common : they never occupy the whole area of the disc, and they never extend deeper than to the lamina cribrosa. Further, the condition is nearly always met with in both eyes, though not always to the same extent. These points should be remembered in distinguishing a physiological from a pathological excavation. The physiological excavation is merely a broadening out of the normal depression met with at tlie centre of the nerve. The sides, or some part of the sides, of this widened dej^ression are sometimes stee}), even occasionally overhanging, at other tin)es sloping. The result of a steep cujijting is, that on follow- ing the vessels along the disc, towards its centre, they are seen to suddenly come to an end, owing to the straight dip wlaich they make down the side of the excavation. They rcajtpear at the bottom of the excavation, where they are not in focus at the same time with those on the surface of the disc and retina. At the same time, the deeper lying portions often look as if they were not continuous with the others, owing to the change in direction which has taken place in the jiortions hidden from view. The white area of excavation contrasts very markedly with the pink surrounding portion of the disc. The vessels in this white area, which, when those on the retinal surface are in focus, look ])aler, as it were washed out, and on which the clear streak of reflection is absent, assume a more normal appearance on accurate focussing. At the same time, the indefinite white or NORMAL FUNDUS. 41 bluish-white area ou which they lie also comes into focus, and shows more or less of the reticulated steel grey, or blue and white meshwork of the structure of the lamina cribrosa. The mottled bluish marking is very ditierent in different cases, as it is only seen when the nerve fibres have lost their myeline sheath at some distance back. In the more funnel-shaped excavations, the vessels may be traced down the side of the cup. In all cuppings, but most markedly in the sharp ones, the vessels at their points of flexure appear darker, owing to one's looking down upon a deeper column of blood. However sharply Fig. 14. — Physiological excavation of disc— After Frost. the vessels may bend over the margin of the cup, they are always seen to course over some portion of the normal disc before passing into the retina. Ophtlialmoscopic appearances of the normal choroid. — When the pigment in the hexagonal cells of the retina is abundant, all that can be seen of the choroid is the red or orange-i-ed colour, reflected from the blood, in its numerous blood vessels. The intensity of this colour, too, is, as has been said, dependent upon the density of the pigment, so that the red is much less pronounced in very dark individuals. Where the pigment in the hexagonal cells is scanty, on the other hand, the 42 EXAMINATTOX OF THE EYE. vessels of tlie choroid come into view. As the larger trunks of the choroiilal veins lie towards the equator of the eye, the structure of the choroid is often more visible at the peri[)hery than at the centre, wliere too the pigment is usually more dense. On this account, it is comparatively rarely, under normal con- ditions, that much of the choroid is seen at the centre of the fundus. The choroidal veins, when visible, present themselves as a dense network of broad and narrow stripes, of a pale red, orange, or yellow colour, separated by lighter or darker inter- spaces, according to the amount of i)igment contained in the stroma of the choroid. If there is a great absence of pigment, both in the. hexagonal cells and in the choroidal stroma, the veins of the choroid may be visible in their finest ramifications, or, at all events, as far as the magnification of the ophthalmo- scopic image admits of. The interspaces then apj^ear non- pigmented, and reflect a yellow or reddish-yellow light. They vary in size, and their shape is mostly that of an irregular rectangle. The interspaces are more elongated towards the periphery than at the centre, in the region of the macula. Sometimes the choroid itself is well supplied with })igment, although that of the retina is sparse. The interspaces are then darkly jiigmented, and only the larger vessels are visible. A zone at the extreme periphery of the choroid, Avhich lies aiiterior to the equator of the eye, cannot be seen Avith the ophthalmoscope. CHAPTER III. DISEASES OF THE EYELIDS. The obvious function of the eyelids is to protect the eyes from external injury, and thus preserve the transparency of the cornea. The lids, with their lashes or cilia, prevent substances of any size coming in contact with the cornea, and furnish an oily secretion which lubricates the surface, and thus obviates any intransparency of the cornea which might arise from the drying or hardening of the superficial layers of its epithelium. The tears, too, aid in this, and at the same time tend to wash away any minute substances which may lodge within the eye. The lid aperture varies considerably in length in different individuals, and always appears larger when the eyes are prominent, and smaller when they are sunken. The points where the upper and lower lids meet at an angle are called the outer and inner canthi. llather less than a quarter of an inch from the inner canthus, and just at a point where the lid margins begin to narrow, are situated, both above and below, the slight papilliform elevations in which the little channels or canaliculi leading to the tear sac end. The small punctiform apertures leading into the canaliculi are the so-called ^/imcto lachrymalia. The eyelashes spring from the outer portion or edge of the margin of the lid ; their roots, which are from 2 to 3 mm. long, being embedded in the dense fibrous tissue. The substance of that portion of the lid which covers, or is directly applied to the eye, is composed of four layers, which, proceeding from within outwards, are (1) the conjunctiva; (2) the tarsus ; (.3) a layer of muscular fibres ; and (4) the skin. In this situation, the conjunctiva is very closely adherent to the underlying dense fibrous tissue or tarsus. Beyond this, it is thrown into folds, and only supported behind by a much looser connective tissue. The tarsus of 44 DISEASES OF THE EYELIDS. the lower lid is an insignificant, narrow, and thin structure ; in the upper lid it is thicker and much deeper, and to its free margin is attached the tendon of the levator palpebrai superioris. An oily secretion is formed in the tarsal or Meihoniian (/lands, and passes out of nunieroiis ducts which oiien along the margin of the lid. Innncdiately below the skin of the lid, which is extremely lax and movable in all directions, is the orhicular muscle, the function of which is to close the eyes. This nuiscle, which is supi»lied by the seventh nerve, is a large Hat structure, composed entirely of voluntary muscular fibres, and extending over the margins of the orbit, above and below. It has tendinous attachments to the inner and outer i)alpebral liga- ments. The upper lid is raised by the levator palpebrte superioris, which is innervated by the third nerve. To some extent also that muscle receives assistance from a bundle of non-striped fibres, which lie under the conjunctiva, and are attached to the free edge of the tarsus. These fibres are generally called Miiller's muscle ; they also exist in the lower lid, and are innervated by sympathetic nerve fibres. Blepharitis. — This is one of the most common afiections. It often occurs in children who are either strumous or ill- nourished, and dirty and illcared for. It is then frequently associated with phlyctenular conjunctivitis and keratitis (q.v.). The inrtammation begins with hypera^mia and increase of the secretions. When this is not attended to, the secretion becomes fibrinous and glutinous, and seals the eyelashes together, forming crusts or scales, under which a process of ulceration, leading to destruction of their follicles, takes place. The affection is met with in very ditterent degrees of severity, from what is merely a tendency to slight scaliness of the lid margin, to the formation of marked pustules, the irritation of which causes considerable ujdenia and infiammatory swelling of the lid. A sufliciently useful etiological classification of cases of blepharitis would include three groups, which, however, can hardly be said to be always absolutely distinct. The so-called strumous cases, already referred to, form one of the groups. They are often associated at times with attacks of phlyctenular infiammation of the conjunctiva and cornea. Another group would include the cases which are more or less evidently con- nected with a chronic catarrhal condition of the tear sac. The last group would comprise those of herpetic or eczematous blepharitis, as the third variety has sometimes been called. In BLEPHARITIS. 45 these there is an absence of the strumous element, and usually, at the same time, of any evidence of auto-infection from local sources. They mostly occur in adults, often along with more general eczema of the skin of the lids. The worst cases of blepharitis belong to the two first groups. The inflammation in them often goes the length of ulceration, and this ulceration leads to greater or less destruction of the eyelashes. In old-standing cases it is common, indeed, to find a complete or practically complete absence of eyelashes. This gives rise to an ugly, red, blear-eyed appearance, which is very characteristic. Short of this there may be an alteration in the colour and character of the lashes, many of those remaining being misdirected, and thus leading sometimes by their inver- sion to irritation or ulceration of the cornea. The ulcers of the lid margin, as they ex- tend in depth, partially or completely destroy the hair follicles, and then cause these changes in, or the loss of, the eyelashes. In the treatment of all cases of blepharitis, the first step should be to remove the crusts or scabs which have formed, and to epilate, with the cilia forceps, all the eye- lashes which present a dis- tinctly abnormal appearance in their colour, their thick- ness, or the direction of their growth. The subsequent treatment must depend upon the etiology of the local inflammation, as well as to some extent upon the severity of the changes which have been produced. Sometimes, when the ulcers of the lid margin have become to a great extent confluent, a really satisfactory preparation for local applications can only be got by first cutting all the lashes off with a pair of scissors. This is comparatively seldom necessary, however. Before attempting to remove the scabs, it is best, in the more pronouncedly impetiginous cases, to apply a starch poultice, in order to soften them. They can afterwards be carefully and thoroughly picked off with a piece of quill, without causing much pain. Until this is done, any epilation that may be required should not be begun. Besides saving trouble, owing to many of the diseased lashes coming Fig. 15. — Blepharitis. 46 DISEASES OF THE EYELIDS. away with the scabs, it is then easier to see from the Uttle ulcer pits wliich laslies it is advisable to pull out. When from the raw surface thus exposed there is found to be an exudation in which there is an evident admixture of pus, which is only rarely the case, and only in the strumous variety of blepharitis, it is well to paint the lid margin over once with a 5 per cent, solu- tion of nitrate of silver, dabbing the solution well in to the ulcers with the camel's-hair brush. This should be followed up by the use, three or four times daily and for a quarter of an hour or so at a time, of compresses soaked in a ^ per cent, solution of the neutral subacetate of lead. After these have been used for a few days, recourse may be had to the yellow oxide ointment. ^ Hydrargyri oxidi flavi ..... 10 grs. Vaselini albi ....... ^ oz. This should be well smeared along the lid margin morning and night. Occasionally from neglect, or owing to some particularly marked delicacy on the part of the patient, often from both combined, and always in young children, the lid margin inflam- mation is not only ulcerative, but is associated with a great deal of deep infiltration, so that the tissues of the lid, and especially the tarsus, are much swollen and thickened. In such cases the ordinary treatment is of no use. As the eyelash follicles are then irretrievably destroyed, and there is consequently no good attemi)ting to save them, the best treatment is to freely scrape away the ulcerated tissues with a small Volkmann spoon, and then undermine the skin and transplant it over the comparatively healthy raw surface which is left. The general treatment in the case of the strumous variety of l)lepharitis should be on the same lines as that referred to in con- nection with iihlyctenular keratitis ((/.v.). Dark glasses should be worn outside in summer, and also in winter when there is snow on the ground. The skin should be kept clean by frequent baths, and cod-liver oil or syrup of the iodide of iron given internally. In a number of cases of less severe blepharitis, wliicli do not ra})idly improve by the use of the yellow oxide ointment, effi- ciently ai)plied after the scabs and crusts and diseased eyelashes have been removed, it becomes advisable to slit up the canaliculi. This should always be done when any regurgitation of mucus or muco-pus can be got by pressure over the tear sac. In any case, it should always be done whenever a blepharitis exists BLEPHARITIS. 47 for a long time on one side alone. In such a case it often happens that the blepharitis rapidly disappears without any further treatment, although it may previously have resisted other therapeutic measures. There is not, however, the same justifica- tion for early interference of this kind in bilateral cases. In them it should not be undertaken, unless there should either be definite evidence of a catarrhal state of the mucous membrane of the tear passages, or a decided rebelliousness to the treatment I'ecommendecl above. The eczematous variety of blepharitis, besides being practi- cally only met with in adults, never assumes the impetiginous type which characterises so many cases in strumous children. Hyperiemia of the lid border, with a scaly crusting, and some- FiG. 16. — From a case of severe blepharitis in which tlie tarsus was greatly thickened (tarsitis). The condition is also known as sycosis tarsi. times a sort of herpetic eruption, are the ajjpearances presented by this form. In the milder degrees the lid margin has a look almost as if it had been dusted over with flour, although the numerous small scales are hardly as white. The treatment should consist in bathing with warm water, the lid margins being well rubbed with a wet pledget of cotton- wool, and the following ointment applied night and morning after the bathinc; : — R Zinci oxidi Ichthyol Yaselini albi 20 grs 1 „ i OZ. Attention should be paid to the conditions under which the eyes are used, and sources of irritation, such as dust or smoke 48 DISEASES OF THE EYELIDS. or iinpure air, reinovod as far as j)ossible. Dark glasses are also sometimes useful. Further, it is always advisable to correct any existing error of refraction, especially for near work. In troublesome cases it is well to recommend an anti-gouty diet. It is specially important to knock oti" alcohol, particularly if, as is often the case, it hajipens to be freely indulged in. Hordeoltun or stye. — The stye is essentially a furuncle of the lid margin. 1'he inflammation arises in the sebaceous glands surrounding an eyelash, no doubt as the result of some form of infection. As a rule there is little difhculty in recognis- ing a stye. Sometimes, when the inflammation surrounding the eyelash bulb has caused very consideraljle cedema of the lid and chemosis, and particularly if the stye is situated near the outer canthus, the cause of the tedema may not be so apparent. The site of the pain on jiressure is then of importance in enabling one to arrive at a diagnosis. On running the linger along the lid margin, or on grasping the lid border between the fingers, a sharp pain wdll be felt when the disturbance is caused by the l)resence of a stye. The acute localised inflammation comes to a point somewhere on the margin of the lid, and thus differs from a sujipurating tarsal cyst, which invariably points on the conjunctival or skin surface. The treatment in the case of styes has to be both })alliative and prophylactic. At first warm compresses of lead lotion (a 1 per cent, solution of the neutral subacetate), or of alum lotion (4 grs. to the ounce of water), may be used. When the stye has begun to point, it may be incised. In doing so, a small open- ing is made in the long direction of the lid mai'gin. Afterwards the thick matter may be squeezed out by pressure between the forefinger and thundi, and a poultice applied. When crops of styes ajjpear simultaneously, or several come on one after another, to which in most cases there is a more or less marked tendency, it is important to take tlie patient's general health into consideration. Usually he is found to be run down, or to be suftering from some gastric derangement. A short course of a natural aperient water should be prescribed, and followed by a tonic containing iron and quinine. Exercise in the open air is also indicated. This treatment is generally efficacious ; but special indications may be present in some cases, as where the diathesis is either markedly strumous or markedly arthritic or gouty. In all cases it is well to use the follow^ing ointment as soon as the acute inflammation has subsided : — !^ Ungueiiti lij'drargj'i'i iiitratis (B.P. ) . . . i drm. A''aseliin albi . . . . , . . | oz. MARGINAL PIMPLES. 49 This should be smeared along the edges of the lids of both eyes night and morning. It may be said to have almost a specific action in preventing the recurrence of this troublesome and painful form of inflammation. Molluscum contagiosum is another affection frequently met with along the margin of the lids. It occurs on the skin of the lids as well, and there the cysts may attain a greater size. The circular shape of the swellings, and the little depression in the centre, give to them quite a characteristic appearance. They are often found in several members of the same family. The affection is common in children, and occasionally goes on to suppuration. The treatment consists in snipping off the smaller growths with a pair of scissors, and in transfixing the larger ones, and pressing out the sebaceous matter which they contain ; the cyst wall may be drawn out, too, with a pair of fine forceps. Warts, papillomata, and translucent cysts also occur along the lid margin. They should be removed with as little mutila- tion of the normal tissues as possible, so as to avoid any mis- direction of the ej'elashes, which is liable to occur from cicatricial contraction. A condition which is often complained of, and generally more on account of its unsightliness than for any great discomfort to which it gives rise, is a sort of blind pimple on the lid margin. Usually there is only one, though occasionally there may be several elevations of this kind at different parts of the margin. The pimple appears as a uniformly red conical elevation. Its base occupies mostly the portion of the flattened lid margin which is in the neighboui'hood of its free outer edge. Often there are epithelial squames at other parts, indicating a slight degree of blepharitis, but this association may be quite absent. These pimples occur mostly in adults, and often in cases which present more or less evident arthritic symptoms. They do not cause much discomfort, and are usually complained of more on account of the disfigurement. This depends partly upon the size, of course, but mainly on the degree of congestion which the little prominences present. The natural duration of the pimples is variable. They may only last a few weeks, but often they remain in much the same state for many months. LTsually, however, in the chronic cases, the redness, which at first is marked, tones down to a great extent, so that the adventitious tissue assumes nearly, if not quite, the colour of the rest of the lid margin, and consequently becomes much less apparent. On everting the lid there is always found to be a little circumscribed area of hyperaemia of 4 50 D18EA8ES OK TIIK EVEL1J)8. the coiyuiu'tiva, rouglily triangular in shaiie, witli its base directed to the port ion of the lid margin on which the pimple has formed, and in chronic cases a yellowish streak com'sing down the mitUlle of the hyperiemic patch. This is simply a Meibomian duct l)locked with secretion which has become more or less calcareous. Even in recent cases it is usual to find a degree of transparence in the middle of the congested con- junctival area, behind which some whitish secretion in the duct shows itself. The treatment consists in emi)tying out this retained secretion. This can be done at first by simply })ressiiig the att'ected portion of the lid between the two thund) nails, which causes the natural exit at the lid margin to burst open and give escape to a sebaceou.sdooking secretion. In cases which have lasted for some time it is necessary to incise from the conjunctival surface, making the cut along the yellow streak referred to, and up to the base of the pimple, and then to press out the contents. The pimple itself in either case then quickly disappears. In recent cases it almost immediately loses its hypenemia, and this of itself is always a cause of satisfaction to a patient who has been mainly annoyed l)y the unsightliness which it has produced. Not unfreipieutly there are found to be other little patches in the lid of the same nature, though rarely as large, but which are not complicated by the jirotrusion at the margin. These should be treated in the same way, and i)referably at the same sitting. An astringent lotion may be used for some time afterwards. Herpes frontalis. — This is a rather uncommon disease. The erujition, which is limited to the one side, generally occurs on the forehead and lids, and sometimes the side of the nose as well. When the branch from the fifth, which supplies the side of the nose, is afiectcd, the cornea may become ulcerated and the iris inflamed. The eruption is generally i)receded by intense neuralgia, which I'arely lasts more than a day or two, though occasionally much longer. The l)lebs, Avliich then a])} tear, are at first clear. After two or three days their contents become muddy ; ulceration then takes place, and they eventually leave scars. The scabs fall off in about two weeks from the ai)pearauce of the eruption, but the neuralgia may continue, although the skin itself is more or less aucesthetic. I have seen the eruption con- fined entirely to the upper lid, and in one case it occurred first on one side and then on the other, after several years' in- terval. I have also seen recurrence on the same side. Herpes frontalis is considerably more common in men, especially old ECZEMA. 51 men, than in women, and is said to occur twice as often on the left side as on the right. The disease has been shown to be produced by a lesion of the Gasserian ganglion, but it is doubt- ful whether this is always the cause. In the treatment an attempt should be made, where possible, to obviate or mitigate the sui)puration of the vesicles by keeping the patient in a room illuminated by non-actinic light, as in the Finsen treatment for smallpox. Locally, when the neuralgia is severe, subcutaneous injections of morphia are useful. After recovery, the patient should, if possible, be sent for change of air, and the diet should be nourishing. Xanthelasma. — This is the name given to a yellow })atch of irregular outline which occurs in the skin of the lids. It is almost always met with in both upper lids at the same time, though the patch may be much larger and more prominent in the one than in the other. It consists of fibrous tissue contain- ing some altered blood pigment. The patches may be removed without difficulty if the patient wishes it, as is sometimes the case, on account of their somewhat unsightly appearance. Eczema may extend to the lids from other parts of the face, or begin originally in the lids as an extension from a con- junctivitis or a blepharitis, which, as we have seen, is in reality nothing else than an eczema of the lid margin. Some people are particularly subject to this ; thus I have several times seen an acute eczema of the lids set up by compresses of corrosive sublimate solution even in the dilute form (1 in 5000), in which it is found useful as an antiseptic preparation in various affec- tions of the cornea, and as a dressing after operations on the eye. It is occasionally also set up by atropine, when used as an anodyne and mydriatic, in different affections of the eye. Conjunctivitis in children is frequently associated with eczema. It is then often due to the practice of poulticing the eyes, which is a common popular remedy, leading to much increase in the severity of what would be otherwise very slight ailments. Sometimes, however, the eczema is produced by the same micro- organism which causes the conjunctivitis. In adults, zinc ointment with or without the addition of a little ichthyol, or boracic acid ointment, are as good local appli- cations as any ; in children, perhaps nothing is better than Pagenstecher's ointment, the part being well washed first with black soap and water. Milium, or small, circular, white tumours, rarely more than a pin's head in size, are often found in considerable numbers in 52 DISEASES OF THE EYELIDS. the skin of the lid and cheek. Tlic ei)idermi.s covering tliem is very thin, so that they are of a pearly white colour. They arc removed by incision, and by squeezing out the coni])ressod and altered epidermis which they contain. Chalazion, or tarsal cyst. — A very common cause of circum- scribed swelling in the lid is a retention cyst in the !Meil)omian glands of the tarsus. The retention gives rise to an inflammatory new growth, the size of which may vary greatly. After having attained to a certain stage in its development, the tarsal cyst tends to become inflamed. The inflammation may be associated with considerable (edema of the whole lid. It always then causes more or less pain, though an inflamed tarsal cyst is not so painful a condition as a stye. The inflamed cyst not unfre- FlG. 17. — Shows rouuil swelling in upper lid eaused by large tarsal cyst. quently bursts of itself. When this happens, it always does so at some point on the conjunctival surface. ]\Iore often, after persisting for two or three days, the inflammatory symptoms subside, and the swelling diminishes in size, leaving only the hard lump which characterises the chronic cyst in this situation. A tarsal cyst may occasionally undergo spontaneous absorption, either with or without having become inflamed. The cyst may occur in any part of the thickness of the tarsus, and may, as it increases in size, extend either towards the con- junctival or skin surface of the tarsus. It is easily felt as a firm mass, over which the skin is usually freely movable. Most frequently it is not long before the adjacent conjunctiva is found to be altered in its appearance. A darker, somewhat translucent, coloration, and sometimes a more or less evident CHALAZION. 53 localised prominence of the conjunctiva, then marks the position of the cyst. The treatment which should be adopted is to incise the cyst, shell out its contents, and afterwards break down its capsule or wall. Generally it is best opened into from the conjunctival surface. The incision in the conjunctiva should be made in a radial direction, at right angles to the lid margin. It should freely open into the cyst through the discoloured portion of the conjunctiva. By then pressing the lid between the thumbs of either hand, the cyst contents are squeezed out. With a small metal scoop any remaining debris may be shelled out, and at the same time by a little rough scraping with the same instrument the sac wall be sufficiently destroyed. Too much or too rough Fig. 18. — Shows the appearance on the coiijimctival surface of the same tarsal cyst. scraping is apt to cause an unnecessary amount of ecchymosis. In the less frequent cases in which the cyst mainly extends towards the outer surface of the tarsus, and thus comes nearer to the skin of the lid, the incision may be made through the skin. It should then be made })arallel to the lid border, and followed by the same manipulations as just described. An incision in this situation and direction leaves practically no noticeable scar, owing to the natural wrinkling of the lid skin. There is no certain means of preventing the subsequent recur- rence of the tarsal cysts. If the little operation described has been properly carried out, there is never any recurrence at the same spot, but in many cases there is a decided tendency for 54 DISEASES OF THE EYELIDS. other portions of the tarsus of both U})per and lower lids to lx>come the sites of other cysts. Often a considerable time — it may be years — elajtses between the formation of one cyst or one crop of cysts. Occasionally, if the condition is observed when just beginning, the cyst may be dis})ersed by pressing the lid firmly between the forefinger and thumb. This treatment is generally only applicable where, while treating one or more fully-developed cysts in the ordinary manner by incision, others are found to be i>resent which are just in process of formation. Otherwise, it is seldom that one has an opportunity of i)utting it in i»ractice. No doubt the cleansing, too, of the conjunctival .sac once or twice daily with boracic acid solution is a useful precaution to take. For instance, the lotion may be u.sed in the morning, after the secretions have to some extent become retained during sleep, and again at any time, as on a dusty day, that there has been some more than ordinary cause of iri'itation. The occasional use of a mild astringent, such as the tannic acid solution, referred to in the treatment of conjunctival hypera?mia, may be also recommended. Chalky infarcts in the ^leibomian glands are met with mostly in elderly people who have suffered from chronic liypera^mia of the conjunctiva. When these little yellow concretions project beyond the surface of the conjunctiva they are apt to set up irritation by scraping against the cornea, and should then be removed. Trichiasis, sometimes occurring as a congenital abnormality, but more frequently as the result of blepharitis, is a misdirection of the eyelashes, which gives rise to more or less irritation by their rubbing on the cornea. The condition is called trichiasis. Treatment. — When the trichiasis is only partial, a temporary improvement is obtained by ejjilation. In some cases where a few eyelashes only have been left altogether, the patient may pro- cure for himself a ])air of forceps, and have the eyelashes removed whenever they cause irritation. A radical cui'e can, however, only be obtained 1)y some operation. The simjdest, where a few cilia only are misdirected, is destruction by the actual cautery, or preferably by electrolysis, of the follicles from which they grow. In more general trichiasis some operation for the transplantation of the follicles (see under entropion) has to be adopted. Entropion. — When the lashes rub against the cornea, owing to an incurving of the lid margin, the condition receives the name of entropion. Of this there are two principal varieties, spasmodic or muscular entropion and cicatricial entropion. The TRICHIASIS 55 most common source of the first variety, wliioh is mostly met with in the lower lid, is some irritation of the eye which gives rise to spasmodic contraction of the }»alpel)ral portion of the orbicularis. Under such conditions the inversion of the lid is favoured by a lax condition of the skin, and a narrowness of the l^alpebral aperture. It is very often met with in old people after operations. The treatment of spasmodic entropion must consist both in mechanically counteracting the inversion of the lid and in removing the irritation which leads to the frequent forcible orbicularis contractions. In a number of cases, and particularly in those in which there is only a temporary source of irrit?<,tion, as after a cataract or other o})eration, all that is necessary is to Fig. 19. -Trichiasis, showing iuverteil eyehishes aud the resulting corneal intianiniatinu. reduce the inversion with the finger, and, after carefully drying the .skin, paint on collodion. The lid must of course be held down, and somewhat everted, until a sufficiently thick layer of the collodion has had time to dry, and thus keep up the mechanical effect. This treatment may be tried, before resort- ing to anything more radical, in all cases which have not lasted very long, and in which the lid has not, as it were, got a .set in the inverted position. The collodion has frequently to be reapi)lied — at least once daily, this depending upon the extent to which the layer becomes softened by overfiowiug tears. At the same time the local irritation should be allayed by frequently bathing the eye with warm boracic acid lotion, and afterward.s dropping in a solution of cocaine. 56 DISEASES OF THE EVELTDS. Dark glasses should alsf) Ije Avorn, aiul reading or writing disallowed for some days. Although the collodion treatment is often successful in earlier cases, there is in many a tendency to rela})se. In many, again, the treatment fails to give even tenijiorary relief. Recourse must then be had either to a thread operation, or to excision of a piece of the redundant lid skin. The nio.st commonly employed thread operation is known as Gaillard's. This con- sists simply in jiassing three or more loops of thread beneath the skin of the lid, and knotting them on jtieces of drainage tubing at a greater or less distance down the cheek. One end of a thread, which must be aseptic, is entered immediately below the lid margin, and passed downwards for an inch or so below the skin towards the cheek before being brought out. The other end is entered in the same way, close to the first. This forms a loop. The three or four loops thus placed close to the lid margin are then knotted. They maj^ be allowed to remain as long as they do not produce too much ii'ritation, and the tracks they form are afterwards replaced by cicatricial bands, which render the mechanical effect permanent. This little operation is both simple and efficacious. It has the disadvan- tage, however, of leading to a somew^hat unsightly fold of the skin of the lid. Another thread ojteration, which may be sub- stituted for it on this account, and which is also more .suitable in cases in which there is no marked redundancy of skin, is the following : — Two or three loops ai'e formed at the bottom of the conjunctival sac, by passing the two ends of each thread, parallel to each other and close together, from the bottom of the sac ujjwards underneath the skin, and out immediately external to the lid border, where they are tightly knotted to- gether. For ordinary senile entropion, however, thei'e is no more immediate and satisfactory cure than the excision of a portion of the lid skin. The thread operations need only be resorted to when the patient is averse to any cutting. When properly done, the removal of skin leads to a permanent rectification of the lid inversion. The only difficulty in the proceeding is to make sure of excising just the right amount of skin. If too little is taken, the entropion, though not as great, may be quite as troublesome as before, and an excision of too large a jjiece will convert the condition into a more or le.ss unsightly eversion. On the whole, it is better to err on the side of removing too much than too little. At all events, the patient will usually be better pleased. A slight degree of ectropion, amounting as ENTROPION. 57 it does in such cases to little more thau a withdrawal of the lid margin from the eye, is of little consequence, j»rovided always there is no decided eversion of the punctum laehrymale. It is well, therefore, to take care not to include too large a piece of skin to the inner end of the lid in the [)ortion excised. In order to get the best effect, the upper limit of the excised portion should come close to the lid margin, except to the inner side, where it should curve away from it. After the slight bleeding has been stopped by pressure, the edges of the wound should be brought together by three or four sutures. The dressing (protective, iodoform, cotton-wool) may be changed after forty-eight hours, the stitches removed, and the linear scar covered by a piece of court plaster. The scar eventually left is quite unnoticeable. In some children entropion is a congenital condition, and then has quite a characteristic appearance. The lashes, though rubbing against the cornea, do so, not with their points, as in other cases, but are so applied as to be parallel with the cornea, and consequently produce little or no irritation, so that the attention of the parents is generally only attracted to the con- dition on account of the watering of the eye to which it gives rise. This variety of entropion is probal)ly due to an abnormal development of the orbicularis in the vicinity of the lid margin, and is cured by removal of an elliptical piece of skin. Another common variety of muscular entropion is that met with in cases where the lid has lost the support of the globe, and this may occur in both upper and lower lids, and be a source of irritation to the conjunctiva. It is seen both when the eye is absent altogether and no artificial eye has been worn, and where there is shrinking of the eye, or 23htMsis hnlhi, from any cause. Cicatricial entropion. — Cicatrices in the conjunctiva, and shrinking of the subconjunctival tissues generally, lead to in- version. The cicatrices may be the result of both accident and inflammation, and this form of entropion is equally frequent in both upper and lower lids, and on the whole more troublesome in the former. The most frequent cause of cicatricial entropion is trachoma. The rubbing of the eyelashes against the eye is not only a source of great irritation, but leads to an aggravation of the corneal inflammation which is so often associated with trachoma; or when originated traumatically, to corneal abrasion, and subsequent ulceration and vascularisation. The main aim, therefore, in operations for cicatricial entropion is to remove the trichiasis. To do this without sacrificing the 58 DISEASES OF THE EYELIDS. eyelashes, it is necessary to transplant the lid margin. ^Nfany dirterent methods of doing this have been practised, few of which can be said to be conifiletely satisfactory, and to fully secure the patient against recurrence as the cicatricial contrac- tions become more and more pronounced. With few and un- important exceptions, the various methods in vogue may be divided into two classes. In the one, a transplantation is effected by merely loosening the connection between the cilia- carrying border of the lid and the subjacent tissues, and sliding the bridge thus formed u])wards, at the same time securing its reattachment in the altered i)osition by suitably ])laced sutures. In the other, an attempt is made, in addition, to cover the tissues from which this strip or bridge is displaced with a pedicled skin-Hap from the lid itself, or with a piece of skin or mucous memljrane taken from a distance. From my own experience of operations for cicatricial entro- pion, I believe most of the methods which have been advocated are capable of giving fairly satisfactory results. They are, however, in my opinion, not equally suitable in all cases. For instance, the transplantation of a pedicled piece of skin, to fill up the s[)ace left bare by an intermarginal incision which detaches the flap containing the eyelashes, is most serviceable in cases of partial trichiasis, where the inversion of the cilia is found oidy at the outer or inner portion of the lid. For com- plete trichiasis, it is not oidy difficult to execute efficiently, but it leaves a decided disfigurement. Transplantation of an un- l)edicled graft of skin is not to ])e recommended at all ; even if the graft takes, which is by no means always the case, it eventually shrinks, and the effect is lost. Transplantation of mucous membrane from the lid has the same inconveniences, thougli to a less extent. To get a good result, the portion transplanted must be j)retty broad (^ in. or so). The healing process is a tedious one ; the immediate result, a somewhat unsightly Ijroad lid margin, and the subsequent shrinking apt to lead to recurrence of the inversion. Yet several operators who have had large experience of this method of treating trichiasis appear to be well satisfied with it. For conqjlete trichiasis, without any scarcity of lid skin, and with little incurving of the tarsus, I consider v. Graefe's modi- fication of an old operation (Jaesche-Arlt), on the whole the most suitable. It is easy to do ; the healing is rapid, and not interfered with by movements on the part of the patient, who need not, therefore, be confined to bed ; and the tendency to recurrence after it is not particularly great, if care be taken OPERATIONS. 59 to make a sufficiently deep intermargiual incision. Where, in addition to complete trichiasis, the tarsus is very much shrunken and incurved, it is better, I believe, to substitute another easily performed operation, one which was first recommended by Panas. All operations on the upper lid are facilitated by being Fig. 20. — Snelleu'.s damp. R for right eye. | L for left eye. rendered bloodless by the use of a clamp devised by Snellen. This consists of a double-bladed instrument, in the shape of a forceps with broadened-out extremities. The fiattened end of the lower blade has on the one side a concave cylindrical surface, which is applied to the eye, while its other side, that turned to the inner surface of the lid, is convex. The outer 60 DISEASES OF THE EYELIDS. blade consists of a broad rim, the external measurement of which is rather greater than that of the lower blade. It rests on the skin of the lid, and is screwed down upon the lid, squeezing it on to the one lying between the eye and lid. The rim, when screwed tight, thus completely compresses the tissues and prevents bleeding. V. Graefe's moditication of Jaesche-Arlt's operation is done as follows : After a^jplying Snellen's clamp, an intermarginal in- cision is made with a tine bistoury, by which the lid is separated along its whole margin into two la3'ers about | in. deep. The upi»er layer must contain the whole of the cilia and their bulbs. At either end of this incision two vertical cuts are made down upon it through the skin, | in. or more in length. An elliptical portion of skin is next removed from the surface of the lid. Two or three stitches are then introduced to unite the lips of this wound, the effect of which is to arch up the central portion of the detached layer carrying the eyelashes. Finally, the outer and inner corners of this layer are stitched up to points about \ in. higher on the other sides of the vertical incision wounds. By this means, traction is exerted on the other jjortions of the cilia flap. The effect got immediately after operation must be a considerably exaggerated one, as subsequent cicatricial contraction takes place in the site of the intermarginal incision, and the contraction may eventually lead to recurrence if this precaution be not taken. In Panas' opei'ation the removal of any skin from the lid is obviated. It is done as follows : After applying the clamp, an incision is made through the skin and muscle along the whole length of the cilia-bearing portion of the lid. The incision must run parallel with the lid margin and about ^ in. from it. With a i)air of scissors the tissues are then cleared from the tarsus, both upwards and downwards. The upper dissection should extend to somewhat beyond the ujjper margin of the tarsus, while the lower should just stop short of the lid margin. An incision is next made perpendicularly through the tarsus, at the level of the skin incision, and equal in length to it. This must sever the conjunctiva as well. Threads are then passed through the tendinous attachment at the upper margin of the tarsus, each ends of which are carried down underneath the tissues forming the lid-margin flap, and brought out in the middle of the lid margin. The three or four loops thus laid are tightened and tied over smooth glass beads, to prevent them cutting through the lid margin. The incision in the tarsus thus permits of its lower portion, together with the cilia, being tilted up. The ECTROPION. 61 edges of the skin wound are sufficiently brought in contact by these same loop sutures, the ends of which, after knotting, should be left uncut and plastered down on to the forehead. Ectropion. — Eversion of the lids, or ectropion, may, from the points of view of both etiology and treatment, be considered as occurring in two varieties — conjunctival and cicatricial. Con- junctival ectropion can always be satisfactorily treated. Much can also be done for cicatricial cases, but the blepharo-plastic operations, which are rec^uired wherever there is a loss of lid skin, are far from giving, as a rule, results which are comparable to those got in the simpler and purely conjunctival cases. Moreover, much depends upon the kind of operation which the particular circumstances of each case render available or most suitable. In conjunctival ectropion the skin of the lid is either alto- gether normal, or only slightly eczematous, as the result of being frequently irritated by overflowing tears. It is mainly met with in old people, and then principally, and always, in the marked degrees, in the lower lid. Occasionally one sees a great amount of eversion of the conjunctiva of the upper lid in young children. These cases arise from long-standing conjunctivitis, with great redema and blepharospasm. They do not call for any special treatment, so far as the ectropion is concerned. This disappears of itself with the subsidence of the other symp- toms. The main point to note in connection with conjunctival ectropion is the ease with which the practically normal condition of the skin enables one to hold the lid back in its proper position with one's fingers. A conjunctival ectropion is only slowly develojied. It makes its appearance in cases of old-standing or neglected blepharitis and conjunctivitis. The thickening of the lid margin and swell- ing of the conjunctiva and subconjunctival tissue, to which this chronic local inflammation gives rise, is further complicated by a deeper infiltration, which impairs the function of the palpebral fibres of the orbicularis muscle. These fibres consequently fail to keep the lid properly applied to the eye, and it becomes everted. With the comparatively slight eversion which occurs at first there is associated a degree of watering of the eye or epiphora. The further increase of the ectropion is then favoured by the hardening and thickening of the everted conjunctiva, the excoriation of the skin caused by the overflowing tears, and no doubt also by more complete loss of power of the muscle fibres. The treatment suitable for cases of conjunctival ectrojnon depends mainly upon its degree. Where the malposition is only 62 DISEASES OF THE EYELIDS. sli^lit, the lower canaliculus should ])e .slit uj) into the tear sac in the manner elsewhere described. This to a great extent gets rid of the epiphora by admitting of a better excretion of the tears. Any crusts which may be present on the lid margin and on the surface of the everted conjunctiva must also be removed. The conjunctiva is then }»ainted over once daily with a solution of nitrate of silver (5 grs. to the ounce of distilled water), and zinc ointment smeared night and morning along the lid margin, and also rubbed well into the skin of the lower lid. The same treatment may also be tried in the first i)lace for moderate degrees of ectropion (up to 3 or 4 mm. in depth of exposed conjunctiva). It is generally necessary, however, in such cases to combine with this treatment the excision of some of the swollen and redundant conjunctiva. The portion of con- junctiva removed should equal in breadth that of the everted portion, and should be taken in such a way that the highest- lying everted conjunctiva forms its mid-line. Three or fom- stitches may then l)e ap})lied. It is important to remove the conjunctiva well up to the inner canthus. Higher degrees of ectropion should not be treated in this way, as it is not advisable to cut away too much conjunctiva. Two other methods of treatment, which may be employed either singly or, in excessive ectroj)ion, combined, are then more suit- able. These are Snellen's thread operation, and the excision of a triangular portion of the w^hole thickness of the lid, or of the skin alone, from its outer angle. Snellen's operation consists in passing loops of thread from the conjunctiva below the skin of the lid in such a way that, on tightening the threads, the everted portion of the conjunctiva is drawn upon and caused to turn inwards. Subsequently the mechanical effect of the threads is, on their removal, maintained by cicatricial bands, which form in the tracks they have made. The steps of the operation are as follows : A stoutish waxed and aseptic silk thread is armed with a needle at either end. One needle is entered at a point midway along the ridge in the conjunctiva which marks the highest part of its eversion. It is then passed outwards, and when felt just under the skin is directed downwards in the subcutaneous tissue of the lid, and brought out at a point 1 in. or more below the lower orbital ridge. The second needle is entered through the same ridge of conjunctiva, and close to the point of entrance of the first (about 2 mm. from it). It is then carried along parallel to the direc- tion of the other end of the thread, and finally brought out close to it. This forms the loop. Two other loops are placed in the OPERATIONS. 63 same way on either side of the first. The three loops are then knotted firmly over pieces of drainage tubing. The threads are allowed to remain in situ for two to four days, according to the amount of reaction which follows, and are then removed. This little operation, when properly performed in suitable cases, is most satisfactory, and if the canaliculus has been slit, and the treatment of the chronically inflamed conjunctiva continued for some time, there is no risk of relapse. The appearance immedi- ately after removal of the threads is often not very good, as, although the ectropion is overcome, there may be an unsightly degree of thickening of the lid, which at the same time is un- naturally withdrawn from the eye. In the course of a week or two, however, the parts regain a practically normal appearance, the only difference being that the lid skin is not so soft or Avrinkled as it normally is. Two points should be remembered in perfoi'ming Snellen's operation — (1) It is absolutely essential that the threads should be introduced at the highest points of the everted con- junctiva, and not from the bottom of the conjunctival sac, as seems some- times to be done. (2) Again, the knotting of the threads must not only at the time counteract the ectropion, but must also produce an over effect, and cause a considerable degree of inversion, in order to afford a proper guarantee of a permanently successful result. With regard to the other operation referred to, as suitable in higher degrees of conjunctival eetro})ion, it will often be found that there is apparently a redundancy of skin in these cases, and that mere tightening of the lower lid, by pinching up the skin at its outer [lart, will cause the everted conjunctiva to roll inwards into position. This effect can be rendered jtermauent by the removal of some of the skin. It is best to remove a piece from the outer part of the lid, and not from the middle as is some- times recommended. The base of the triangular piece to be removed is formed then by the outermost portion of the lid margin. Two snips with a pair of strong scissors, made from the lid margin, and converging to a point about | in. below it, is all the cutting that is required. After the bleeding has been sufficiently arrested, by pressure and torsion, two or three sutures F'iG. 21.— Showing po.sitiou of threads iu Snelk-u's operation before and after knotting. — After FucHS. 64 DISEASES OF THE EYELIDS. are applied to bring the lips of the conjunctival wound together, and then a few deeper external ones to. unite those of the skin wound. Healing always takes place by first intention, and nothing could Ite better than tlie effect of this proceeding, pro- vided a sutHciently large portion of the lid has been removed. It leads more rapidly to a restoration of the normal api>earance of the lid than Snellen's thread operation, but has the disad- vantage of requiring some experience, in order to be able to estimate properly the amount of tissue which should be removed in order to get the full effect. In the highest degrees of conjunctival ectro[)ion, as big an effect as can be got, without the removal of too much skin by this operation followed by Snellen's, will rarely fail to give a satisfactory result. In any case where the two operations are coml)iued, they should be done in this order, as the skin excision method requires the absence of any cicatricial formation, to admit of the full effect which can be got from it. The treatment suitable in cases of cicatricial ectropion is, as we have seen, influenced by the fact that the eversion of the lid is due to more or less extensive loss of surrounding skin. The operations which have been recommended as applicable in con- junctival ectropion are therefore rarely of use here. They can only be employed in the comparatively slight degrees of cicatricial eversion. Snellen's thread operation, though it may lead to an im[)rovement in such cases, is never particularly satisfactory, as the turning in of the eyelid conjunctiva is then got at the expense of the position of the lid in another respect ; it is always too far withdrawal from the eye, which generally causes an un- sightly appearance. Removal of a wedge-shaped j^ortion from the lid, on the other hand, sometimes gives quite good results. In cicatricial ectropion, however, the wedge should be removed from the portion which shows the greatest amount of eversion. This may be any part. Often it is the middle of the lid. As a rule, and whenever the eversion is at all marked, it becomes necessary to perform a plastic operation. The jiortion of skin which has to be transplanted may be taken from some part in the neighbourhood — from the cheek, the forehead, the temple, the side of the nose, or, in the case of cicatricial ectro- pion, of the lower lid, even from the upper lid. In all these cases the flap taken should, of course, be a pedicled one. Sometimes, owing to the absence of any sound skin from which to secure a pedicled graft, a ])iece of skin completely detached from some other part of the body, preferably the arm or leg, may be used as a graft. This proceeding has the inconvenience OPERATIONS. 65 that, although the transplanted skin always, with proper care, retains its vitality, and becomes adherent in the gap to which it has been transferred, it has, nevertheless, subsecpiently an in- variable tendency to shrink to a considerable extent. Often this shrinking is so great, that, notwithstanding that the graft has been taken originally a great deal larger than required to make up for the lost skin, the effect of the operation is gradually practically reduced to little or nothing. After a large experience of such operations, I am convinced that they should never be undertaken except where it is quite impossible to get a flap from any part of the face. The patient should then not be encouraged to exjject too much. As there is no local loss of substance resulting from failure in such transplantations, there is always the possibility of repeating them. Indeed, it is usually necessaiy to do so once or twice, to get a fairly good permanent result. The main points to be attended to in making a large skin graft from a distance are — to secure asepsis in both wound and graft, to avoid interfering too much with the graft, to remove all fat from the skin to be grafted, also any blood clot from between it and the wound, to cut the graft sufficiently large, and to allow the first dressing to remain for six to ten days without being changed. The first step in the operation should be the freeing of the traction which causes the eversion of the conjunctiva. An incision is made in the skin or cicatricial tissue, parallel with the whole extent of the lid margin and close up to it. This is con- tinued in depth with the knife, or with a pair of scissors, so as to form a flap composed of the conjunctiva, the layer of muscular fibres, and the lid margin. This flap is freed suffi- ciently to enable the conjunctiva to be easily held in its proper position and turned towards the eye. Three horse-hair loop stitches are then passed through the margins of the upper and lower lids, and the free ends knotted on the lid which is not the site of the operation. This secures the retention of the flap in its proper place, and also fairly well the desired immobility. A gaping wound is thus left, which has to be filled with the graft. Before, however, cutting the graft, a suture may be placed at each angle, and also one or two through the upper edge of this wound, ready to be used for keeping the graft in position. By doing this, any bleeding at the time of placing the graft is avoided. The graft itself is next cut, and of a size at least half as big again as the gaping wound it has to fill. It is best to remove the skin with the underlying fat. This can be done quickly and more satisfactorily than dissecting it free from fat. 5 G6 DISEASES OF THE EYELIDS. The fat is afterwards removed from tlic excised i)ortion of skin, whicli is then ready to be i»hiced in position. By the time it is ready, the wound, on which a compress dipped in corrosive solu- tion has been meantime held by an assistant, has usually stopped bleeding. The free ends of the sutures, which have been placed at points surrounding the wound, are then carried through corresj)onding parts of the edge of the graft, and knotted. These are usually sufficient to hold the graft in its j)lace, but it is well to further secure it against risk of displacement by means of strips of fine court plaster. The whole may then be covered by a piece of ordinary protective, powdered well over, and esjjecially at its margins, with iodoform. A good large pad of Fig. 22.— Conjunctival ectropion of lower lid. absorbent cotton and a bandage comi)lete the dressing, which is not disturbed for at least five or six days. The great advantage which a pedicled flap taken from the neighbourhood has over a graft from a distance is, that it shows little or no tendency to shrink subsequently. When a plastic operation of this nature is properly performed, the flaj) always retains its vitality. The one objection which might be made is, that a scar is necessarily left at some previously more or less normal part of the surrounding skin. This scar should, how- ever, always be linear, and is then not by any means so un- sightly a deformity as that which calls for operative interference. It is important, liowever, to give quite as much care to the ECTROPION. 67 stitching up of the wound from which the Hap is taken as to the stitching of the flap itself into the gap which it has to fill up. Tension must, of course, be avoided, and this is best done by freely undermining the skin before stitching. The operation must be done aseptically ; the ectropion must be reduced completely before the flap is cut, and this either by an incision close to and parallel with the lid border, as already described, or in continuity with a flap, beginning from incisions made at a greater distance from the margin ; according to the operation which it is proposed to do. After this the lids should be temporarily sutured together. The flap must be cut suffi- FiG. 23. — Cicatricial ectroi)ioii of tlie upper lid. ciently thick, and the })edicle be sufticiently broad. If, after cutting it, it should turn out to be rather short, it is better to get the remaining length recpiired from another place if possible, than to risk narrowing the base. If this is not possible, it may be lengthened by undermining the skin at its base. Especially when operating for cicatricial ectropion of the lower lid, care should be taken that the depth of the skin-flap is sufficiently great at the inner angle. Finally, the flap should be very carefully stitched to the edges of the gap to be filled, by a large number of sutures. The dressing should be the same as that de- scribed above, but need not remain undisturbed for the same length of time. GS DISEASES OF THE ]-:M-:ET])S. A pa?TS?'.s of Miiller's muscle. It is associated with myosis, and sometimes with diminished intra- ocular tension, and depends no doubt on some lesion of the sympathetic nerve. Operations for ptosis. — An operation, the object of which is to permit of the possibility of raising a drooping lid, must of course be performed in such a manner as to interfere as little as possible with the power of closing the lid. Eemoval of an elliptical fold of skin from the lid can consequently only be employed in cases where the ptosis is of moderate degree, and where there is a redundancy of skin, or at all events the amount of effect produced must be carefully regulated to admit of a sufficient degree of closing. In most cases some other operation will be found more suitable. After considerable experience of the various operations which have from time to time been recommended, I have found the method devised by Hess the most satisfactory. Of other oiiera- tions, those of Birnljacher ^ and Eversbusch ^ are also capalile of giving good results. Hess's operation is done as follows : An incision is made along the whole length of the eyebrow, which is first shaved off. ^ Cenlralhl. f. j)Takt. ^iM^fCTi^., Leipzig, 1892. - Kli)b. MunatM. f. Aufjcnh., Stuttgart, 1883. 70 DISEA8KS OF THK KYKLTbR. a \6^ ^ a From this incision the skin ot thu litl i.s undermined to close up to the ciliary margin. Three loop sutures are then passed through the skin of the lid from without inwards at about its middle. The ends of each suture are carried below the skin and brought out on the forehead, half an inch or rather more above the incision in the eyebrow. The needles must pass freely in the pouch made below the lid skin, and then be pushed below the skin of the forehead from the upjjer margin of the incision. The three loops thus made are pulled tight a)Kl tied over bits of drain- FiG. 24 shows the position of tlu- '^^^ tubing. A continuous suture incision in the eyebrow, of the is then used to close the eyebrow loops on the skin surface, anil ^yound. (8ee Figs. 24 and 25.) liv the dotted line the extent of , ^ . «• . r /■• the pouch of undermined skin. ^^^ permanent effect of this ojjeration is got by the healing together of the large surfaces of the pouch. The cosmetic eftect is good too on account of the natural-looking fold pro- duced in the lid, and the practical invisibility of any scar when the hair of the eyebrow has grown. The operation is performed aseptically, and conse- quently no disfigurement need result from the fore- head sutures. Nictitatio. — Constant blinking is often met with, and is known as nictitatio. The cause of this, which is most fre- quent in children and young adults, is usually some irritation from the eye itself — conjunctivitis or keratitis. Often the irritation originates in some other fibres of the fifth nerve, not uncommonly, for instance, from decayed teeth. It may also proceed from other parts of the digestive tract. At other times the source of irritation is quite obscure, and indeed the blinking is not seldom apparently merely a habit, which has no doubt been originally set up in some such manner as indicated. If after two or three applications of cocaine to the conjunctival Fig. 25 shows in section the course of the sutures before and after they are pulled tight. 0, point of entrance. a', of exits of sutures passed in pouch lielow skin. BLEPHAllOSPASM. 71 sac the blinking becomes less frequent, or ceases, it is very probable that the irritation proceeds from the eye ; if not, we have to look elsewhere for it — in children, the teeth, or some other part of the digestive system. Often the contraction in the orbicularis is not so general as to cause actual blinking, but is limited to certain of its fibres, mainly those of the lower lid, causing a disagreeable twitch or "twitter " in this region. Blepharospasm, or spasmodic closure of the eyes, may be constant or intermittent. The constant cases are associated with photophobia, and are discussed in the chapter on diseases of the conjunctiva. The intermittent cases are very rare, and mainly caused by irritation of the facial nerves, which causes, at the same time, other contractions of the facial muscles. In some cases of so-called epileptiform neuralgia, there is painful intermittent blepharospasm. (Edema of the lids occurs along with inflammation localised in ditterent parts about the face, and is also frequent in affections of the heart and kidneys, where there is any cause for general oedema. In some people there seems to be a tendency to oedema in this situation, independently of any general cause. This is sometimes called f rigid oedema, and gives rise to a very heavy appearance of the lids, which can be much improved by removing an elliptical piece of the skin of the lid. Occa- sionally a persistent oedema of the lids is left after attacks of erysipelas of the face. This may, without danger, be treated in the same way, if the patient desires it, for the sake of the appearance. Long persisting oedema appears to be associated with chronic conditions of inflammation in the mucous membrane of the nose, to which attention should always be directed when the cause is doubtful. Abscess of the lid is most frequently traumatic, often the result of the breaking down of a blood clot, which has been formed at the time of the contusion. The abscess should be opened and treated antiseptically as soon as fluctuation can be felt. Boils, too, are occasionally met with, principally in the upper lid. Noma is a form of infectious abscess of the lid which occurs, fortunately only rarely, in children. It begins as a pustule, and leads rapidly to great erysipelatous swelling and i-edness, followed by gangrenous destruction of more or less of the skin of the lid. Dermoid cysts are not uncommon in the lids, and are most frequently situated to the temj^oral side of the upper lid, over 72 DISEASES OF THE EYELIDS. the ()rl)ital ridge. They can l)e removed eitlier Ijy Iwiiig care- fully dissected out, or, througli a small o})ening, by jtuncture, followed liy s(|ueezing out of the contents and removal of the sac with a pair of toothed forceps. The incision must be made in either case parallel with the margin of the orbit. Naevi of the lids should be treated by electrolysis, if of any size, or if growing ; other methods of treatment are liable to cause too much destruction of the tissues. Eodent iilcers and epitheliomata are not infrequently found affecting the lids, and have to be removed. The loss of sub- stance thus sustained may be made good by some suitable ])lastic or transplantation operation, but in the case of the lower lid this is often unnecessary, as the deformity, after healing has taken })lace, is often much less than might have been expected. Chancres and vaccine pocks are occasionally found on the lids, being produced in both cases by direct infection of specific matter. The first, from the considerable time which it takes to develop, is sometimes difficult to diagnose ; the vaccine pock, on the other hand, is usually characteristic, and the source of infection readily discovered. Vaccinia is more common in women than in men. There is always either a distinct history of inoculation, or of the possibility of inoculation. A child has been vaccinated ten or fourteen days before the patient is seen. Usually the pock occurs on the lower lid, but there are also to be found one or more ulcerated patches on the margin of the upper lid where it comes into contact with the macerated surface of the primary vaccine ulcer. The swelling is always great, and involves not only the lids but also the cheek. The base of the ulcer is decidedly harder than the surrounding swelling ; but not so distinctly indurated as in the case of chancre of the lid, and the glands are not swollen. There is, comparatively speak- ing, very little pain ; practically no sjiontaneous pain, and but little tenderness to touch. The eye itself seems very rarely ever to be attected. I have not seen the cornea involved in the cases, a dozen or more, that have come under my ow-n observation. Vaccinia of the lid never leads to any alteration in its position, and even the cicatrix left is slight — barely perceptible, OAving, no doubt, to the laxity of the skin in this situation. The syphilitic sore is always a more distinctly clean-cut, eaten-out ulcer, which has taken a considerable time to develop from its first appearance as a pimple at the lid margin. Tlie opposite lid margin is not as a rule ulcerated. The base of the ulcer is greatly indurated ; and the pre-auricular gland — often. SYMBLEPHARON. 73 also, the .submaxillary glands — are swollen. There is no history which can in any way connect the case with vaccination, and usually one which renders a syphilitic contagion possible. Secondary symptoms appear in due course. Sarcoma of the lid is met with as a great rarity in children and young adults. Other uncommon affections in this situation arefatti/tvmours, elejyhantiasis, neuroma, and coloboma. The last may occur along with coloboma of the iris. It should be treated as soon as possible, by paring the edges of the slit and uniting them by sutures, so as to secure a proper covering for the cornea. Blepharophimosis—Anchyloblepliaron. —Chronic affections of the lids, especially such as keep up an excoriation of the skin ^A/n '/)"|\V^ ^^^ m Fig. 26. — Primary syphilitic sore of upper lid. at the outer canthus, may lead to a narrowing of the lid aper- ture, or blepharophimosis. The treatment for this is cantho- plasty {q.v.). When either the complete ciliary margin or a portion of its centre is united with that of the other lid, the con- dition is known as anchylohIe2)haron. Symblepliaron. — When some injui-y or destruction of the two opposing conjunctival surfaces of the lid and eye has taken place, there is a tendency for the lids to grow together, and thus give rise to the condition known as symblepliaron. This is most likely to occur in all cases where that jiortion of the con- junctiva, which forms the fold between the ocular and palpebral coverings, is involved in the ulcerative or destructive processes ; indeed, it is then almost impossible, except by performing some operation to effect a covering of the raw surface, to avoid their 74 DISEASES OF THE EYELIDS. growing togetlier, as, liowever froiiuciitly the two surfaces be separated, healing will slowly take place from the angle between them. When the fold is not involved, the freijuent separation of the opposing surfaces, by making passive movements of the lid, and at the same time dropping a few drops of oil into the conjunctival sac, will generally permit of their cicatrising independently, and thus obviate the symljlepharon. The severity of the alteration caused by symblepharon is very ditierent, according to the position and extent of the adhesion between the conjunctival surfaces. In very bad cases the eye Fk;. 27. — Case showing slight degree of symblepharon of the lower lid. may be rendered almost completely immovable by a gluing of both lids to it. Sometimes the adhesion takes place between the lid and the cornea, and causes a still greater interference with vision than would have resulted from injury to the cornea alone had this not occurred. Adhesions may give rise to diplopia, by interfering with the movements of the eye. Operations for symblepharon. — The wound left after the detachment of the cicatricial tissue, by which the lid has been rendered adherent to the eye, may be covered in different ways. The method of oi)eration to be selected in any particular case will depend on the extent of this denuded surface, as well as on the condition of the surrounding conjunctiva. SYMBLEPHARON. 75 Where the cicatricial band is small and the rest of the con- junctiva healthy, the loss of substance may be made good by a transposition or glissement of the adjoining conjunctiva. The band of cicatricial tissue is grasped firmly with a pair of fixation forceps, and put on the stretch. Its attachment to the cornea is then carefully dissected off with a small bistoury, and the freeing of the lid completed by snipping the other attachments with scissors. The conjunctiva to either side is next undermined to an extent which permits of the edges being readily brought together by sutures. The stitching should be carefully per- formed, and as many stitches as possible used, particular atten- tion being paid to the covering of the lowest part. Where the Fig. 28. -From a case of almost complete symblepharon. Extensive adhesion of lids to cornea. cicatricial band is of some size, it may be turned back and made use of as a partial covering for the raw surface of the inner side of the lid. This may be done by a loop-stitch passed through its apex, then through the thickness of the lid, on the skin sur- face of which it is tied over a piece of drainage tubing. This latter proceeding is seldom of nuich use ; it is generally better, after cutting away the redundant cicatricial tissue, to rely on the frequent use of oil during the cicatrisation of the lid. Another opei'ation which is suited to the same class of cases, and by which perhaps a rather large defect can be covered, is Teale's transplantation operation. By this operation two Hajjs of conjunctiva are taken from either side, one of which is used for covering the inner surface of the lid, while the other serves 7(5 DISEASES OF THE EYELIDS. as a covering for the eye. The Haps are cut as represented in Fig. 29, which is copied from a drawing in Mr. Swanzy's " Handbook of Eye Diseases," altered from liis original one by Mr. Teale himself. The com})lete transplantation, or (/mftuH/ of mucous inetnhrane, has lately taken the place of other operations for symblepharon. Such a method of operating is certainly ajjplicable to cases Avhich would otherwise not admit of interference. The mucous mem- brane may be conveniently taken from the mouth, and should be half as large again as the defect which it is to cover, and devoid of any submucous tissue. Owing to the tendency which it has to curl up, it is impossible to get it into good position without the use of a number of stitches. In order, too, to ensure its applying itself to the wound throughout, it is well to put in one or two looji-stitches as well at the fornix, which are brought through the substance of the lid and tied at the outside. The graft \.\^il*//y Fig. 29. — Teale's operation for syniblepliaron. should not be definitely fixed until all bleeding has stojiped ; it is therefore best to begin with the stitches that attach it to the lid. When there is a redundancy of skin in the lower lid, a piece of skin from this situation may be conveniently used instead of mucous membrane, the character of which it to a great extent slowly acquires. It is much more easily fixed in position, and does not require so many stitches. Snellen has recommended an oi)eration for bad cases of symblepharon, which consists in clothing the inner raw surface of the lid, after it has been detached from the eye, with a fiap of skin dissected from the temple in the immediate neighbourhood of the outer angle of the lids. After cutting the elongated fiap, an opening is made below its base into the conjunctival sac. The skin is then pushed thr(jugh this o})ening, so that its raw surface comes to lie against that of the detached lid, and stitches are introduced to maintain it in this position. T have performed this operation several times, and obtained fairly satisfactory results. CHAPTER IV. DISEASES OF THE LACHRYMAL APPARATUS. AflFections of the lachrymal gland. — Inflammation of the lachrymal gland is a rather rare affection, which occurs both in an acute and chronic form. The acute inflammation is accom- panied by very considerable swelling of the lid and conjunctiva, especially their external portions. The swollen lid is tender to pressure, and through the skin, which is movable over it, can be felt the hard margin of the enlarged gland. Not only does the increased size of the gland cause considerable drooping and more or less complete immobility of the upper lid, but it may also give rise to some protrusion and depression of the eye itself. If it is possible to evert the lid, the lower portion of the swollen gland may be seen pressing forward the fold of conjunctiva forming the transition between the portions covering the eye and the lid. When an abscess forms, it may bur.st either thi'ough the skin or through the conjunctiva ; in either case a fistulous opening is likely to result. The treatment should first be directed towards preventing suppuration by means of ice-compresses, counter-irritation with iodine, etc. ; but as soon as there is fluctuation an opening should be made, preferably, if possible, through the conjunctiva, as a flstula in that situation is not so awkward as one opening through the skin. Inflammation of the lachrymal gland sometimes becomes chronic, or may be subacute from the fu-st. Some of these cases are bilateral, and appear to be mostly syphilitic in their nature. The acute inflammation is most frequent in children, and the cause is usually some trauma. In chronic cases, which resist any other treatment, the palpebral portion of the gland may be excised. Simple hypertrophy or adenoma of the lachrymal gland is also met with, and sometimes the gland, though apparently not very much enlarged, sinks down into the up2)er lid, causing rs DISEASES OF TIIK LACIIIIVMAI. AITARATUS. litosis. In I'itlirr rune excision is necessary, care lieing taken not to interfere witli the tendon of the levator pali)el)ra\ Fibroma of the lachrymal ^land also occurs. Fistula of the laclirymal gland arises from the bursting of an abscess of the gland. Ueiierally the fistula is an extremely Fig. 30. — Transvi-rsc section of tai-f from above Jownwanls and slightly backwards from frontal sinus to first molar tooth. It oj)ened nasal cavity (.1), lachrymal sac (/!), nasal ainful. In some cases of acute inflammation of the sac, healing takes place without any bursting of the abscess ; but in many the skin over the sac becomes more and more thinned, and eventually gives way. This usually takes place at a somewdiat lower level than the sac itself after the tissues above have been infiltrated — at the most dependent part, therefore, of the superficial abscess thus formed. The result of this is that there is a passage of some length formed between the external and internal ojjenings, which has a tendency to become fistulous. Sometimes a more or less extensive necrosis of the skin takes place, so that an ulcer is established in this situation, which may lead to cicatri- cial ectropion of the lower lid. Dacryocystitis is most frecpiently set up by an inflammation originating in the mucous membrane itself, and is probably as a rule the result of extension of a similar condition from the DACRYOCYSTITIS. 83 mucous membrane of the nose, only increased in severity by the irritation which the retention of the secretion produces. •Sometimes it appears to be primarily associated with disease of the bone or periosteum, which is then of a strumous or syphilitic nature. The ordinary inflammation beginning in the sac rarely, if ever, spreads to the bone ; so that in cases where the bone is found to be diseased, and not merely bai'e, which may result from rough treatment, such disease nuist be looked upon as the })rimary affection. A correct idea of the etiology of inflammation of the lachrymal sac is of importance in suggesting a suitable plan of treatment. There can be little doubt that by far the largest Flu. 3o. — Acute dacryocystitis, showing swelling of lids and at antile of nose. number of cases begin as a cold in the head, an attection from which few escape altogether, but to which some are much more liable than others. If the swelling of the nuicous mem- brane of the lachrymal duct jjersists for long, there is a tendency, when any individual ])redisposition exists, to the stagnation and decomposition of the secretions in the sac, which becomes more and more pronounced the more its anterior Avail becomes distended. This sets up an irritation, and leads, as a rule, to blennorrh(ea of the sac, which may be more or less pro- nounced, and which is liable at any time to pass into the acute form of dacryocystitis. When this takes place there has often been a fresh coryza shortly before. Often, no doubt, the acute 84 DTSKASES OF THK LACHUVMAL APPARATUS. jthU'ginonous iiiHaiuiuation wliicli succet'ds the mere catarrhal fhaiigf ill the luiu'ous iia-inliraiie is the result of a deeper itciie- tration tjf the luicrobe.s and toxins. It is remarkable how seldom any complication in the sac is met with in Civses of liiinileiit conjunctivitis. The secretion wliicli passes into the conjunctival sac from the abnormally inflamed tear sac is not infectious to the con- junctiva, and rarely leads either to imrulent intlammation of the conjunctiva or to conjunctivitis if transferred to the other eye, though it is more or less irritating to the lid margin, and thus gives rise to blepharitis. It possesses, therefore, none of the virulence of the pus which is found in a case of gonorrhoeal conjunctivitis. Nevertheless, it is well known to be a source of great danger when any operation is i)erformed on the eye, and the cause in many cases of the Rei)tic hypopyon ulcer which follows slight abrasions of the cornea. By many, strictures of the duct are looked upon as the immediate exciting cause of dacryocystitis ; yet it is remark- able in what a large jiro^iortion of cases probes can be passed with the greatest ease when once the sac has been opened into. Many cases of stricture, where the stricture is far down at the entrance of the duct into the nose, do not give rise to inflamma- tion of the sac ; and as for the strictures which are met with in the other situations where they are common, namely, at the lower orifice of the sac, these are almost invariably the consequence of the destructive inflammation of an acute dacryocystitis, and not its cause. The treatment of blennorrhcea of the tear sac should aim at preventing the occurrence of acute phlegmonous inflammation, and stopping as far as possible the interference with the dis- charge of the tears. The first, however, is the more important ; but as many cases are first seen when the stage of acute inflam- mation has already begun, it is also necessary to consider the proper course of treatment to be adopted under such circum- stances. As soon as the existence of a chronic blennorrhea has been diagnosed, active treatment should be begun without delay. This should consist in making an opening into the sac from above, through one or both of the canaliculi, probing the duct frf)m time to time, so as to maintain its patency, and by astring- ent and antiseptic injections modifying, as far as possible, the character of the secreticjii from the mucous surfaces. The choice of which canaliculus to open is perhaps hardly a very important matter, still there are good reasons for preferring DACRYOCYSTITIS. 85 the upper. In the first place, the lower is then left in its physiological state, and as it has most to do with the removal of the tears, this may be some, though possil)ly only a very slight, advantage. A more practical consideration is the circum- stance that the upper canaliculus is in a more direct line with the duct, so that probes can be passed without stretching the tissues at the opening into the sac to the same extent as is often done when the lower canaliculus is opened, and which may lead to cicatricial contractions in this situation, and consequently to a complication which is apt to prove troul^le- some. The canaliculus should be freely opened into the sac and the knife passed into the sac itself, with the cutting edge directed forward, and then made, by a slight sawing move- ment and slight rotation on its axis to either side, to freely divide any constricting bands which are present in this situa- tion. After this has been done, a medium-sized probe should be passed down the duct into the nose. As has been already said, the probe can usually be passed without the slightest ditficulty. By this treatment a great improvement usually takes place in the course of two or three weeks, but the length of time during which the treatment has to be continued depends a good deal on the chronicity of the case. The reason of this seems to be the tendency to greater and greater distension of the sac, and consequently a greater likelihood of stagnation taking place in it the longer the case has continued. There is a pretty general tendency to do too much. This appears to arise from too great importance being, as a rule, attached to the blocking of the tear duct as the cause of epiphora, and to a too general assump- tion that the blocking is of the nature of a stricture. It should be remembered that it may possibly be a questionable advantage to maintain the patency of the duct at the expense of frequently bruising and otherwise irritating its mucous lining. The two consequences which, in my experience, are apt to follow the use of very large probes and of rejiieated probing are (1) the conversion of a blocking, from mere catarrhal swelling of the mucous membrane, into a blocking from actual sub- mucous stricture, and (2) the tendency to provoke a dacryo- cystitis. The latter would possibly be more frequent than it in reality is from such treatment, Avere the mucous membrane of the sac bruised to the same extent as that of the duct. Another very frequent result of excessive probing is the production of a stricture at the canaliculus entrance to the sac. This is especially caused by large probes, and niore particularly 8G DISEASES OF THE LACHRY>rAL APPARATUS. wlieii the opening along the canalicuhis lias not from the first been prolonged well np to the sac. The raising of the probe, which is necessary to cause it to descend into the duct, con- stantly overstretches and even lacerates the tissues, and thus this troublesome form of stricture arises. Owing to the tendency to this disagreea])le (•omi)lication, it is ]irefera])le to oj)en the upi>er instead of the lower canaliculus. Sometimes the slitting of the upper canaliculus presents consideral)le difficulty. In these cases, and always where there is any ectropion of the lower lid, the lower canaliculus should be slit. The 0})ening got by slitting the upper canaliculus is not so ample, and does not admit of the use 'of very large probes. As regards epiphora, it is interesting and instructive to note the differences commonly met with in the ordinary cases of blennorrhcea of the lachr^nual sac when com^jared with cases in which there is a comi)lete o])l iteration of any channel for the excretion of the tears. In all blennorrhea cases the epiphora is more or less constant and very troublesome. Yet in the vast majority of such cases there is no difficulty experienced in pass- ing a good-sized probe down the duct. After thorough oblitera- tion without catan-h or after complete removal of the sac, on the otlier hand, there is almost invariably little epiphora. Not infrequently this symptom is practically absent. It is clear, therefore, that faulty excretion cannot be the main cause of the symptom, for the removal of which one is mainly called upon to interfere. In fact, there can be little doubt that much of the epiphora is due to excessive secretion of tears, caused by an irritation which originates in the mucous membrane of the sac, and i)Ossiljly also of the duct. The consideration of these facts attbrds one a guide to a rational treatment. And the first ^joint that suggests itself is this : is it necessary, in order to bring about a return to the normal condition of the mucous membrane, to attempt to maintain a constant patency of the ductl No doubt stagnation and decomposition of the mucous secretions and other products in the sac is greatly, if not entirely, the cause of the continuance of the state of irritation. The opening of the duct by probing, not unreasonably, there- fore, appears to be indicated to overcome this stagnation. As, in addition, there is always the risk of a catarrhal inttammation in the sac develo[)ing into a phlegmonous acute dacryocystitis, there can be no question that the sooner attem[)ts are made to check stagnati(ni the l)etter. As soon as we have occasion to DACRYOCYSTITIS. 87 diagnose blennorrlioea of the sac, by finding more or less regur- gitation through the canaliculi on pressure over the sac, a canaliculus should be slit, preferably the upper, for reasons already stated, and the duct probed. The object of this pro- ceeding should not, however, be to bore, as it were, a ])assage for the too copious overflowing tears, but rather to hasten the recovery of the mucous meml)rane and to remove the risk of dacryocystitis. This being the case, the frequency and severity of the manipulations required will be determined solely by the extent to which the mucous membrane will tolerate the necessary interference. In my experience there is too much risk entailed by the use of both very small and very large probes. The former are apt to cause laceration, the latter bruising. Too frequent probing, even with the sizes of probe such as I have found most suitable (one of a diameter of a No. 6 Bowman to one of 1"75 mm. diameter), also generally defeats its object by irritating the mucous membrane too much. Probing should be done at intervals of a fortnight to begin with, and then, if necessary, at longer intervals. Generally, however, three or four probings are sufficient ; nearly always so, if the case has come under treatment early. Syringing the duct, whiqh is often recommended, is, as I have found after a very extensive trial of it, no more effective than simple probing. There is one class of case, however, in which syringing is useful. This is the condition in which the sac has become over-distended, and fills up with mucus or muco-pus, notwith- standing that a probe passes quite readily down the duct. In this rather troublesome complication syringing the sac alone freely with sterilised water until all the secretion is removed, and then with a 10 per cent, solution of protargol or argyrol, is certainly useful. A carefully applied pad of cotton-wool may with advantage be used afterwards to check the refilling of the dilated sac. These syringings should be repeated daily. The treatment is, in fact, much the same in principle as that for cystitis caused by an over-distended bladder, and, though it may have to be continued for some time, is, on the whole, ^■ery successful. The treatment for epiphora due to catarrhal inflammation of the sac, which consists in early opening through the upi)er canaliculus, followed by probing with a moderate-sized prolje at intervals of a fortnight, is almost invariably satisfactory, and leads to rapid improvement or recovery. It is otherwise, how- 88 DISEASES OE THE LACHRYMAL APPARATUS. ever, with cases which liave gone on to dacryocystitis before treatment has heon l)e<,'un. Tliey very often prove more tronble- somc. My exi>eri('nce of sucli cases, which are unfortunately far from uncommon, is tliat it is far safer to avoid probing altogctlicr until all acute synii)toms have subsided. If the case be seen before the tissues in front of the sac wall have become infiltrated, an oi^ning should be made through both upper and lower canaliculi. When an abscess has actually formed, sufficient drainage can only l)e got by an incision through the skin into the sac. The incision should be free, and be made in a line with the duct, but should not l)e begun too high up, so as not to involve the palpebral ligament to any great extent. It is a good plan to stuff the opening thus made Avith iodoform gauze, and to con- tinue this method of dressing until the discharge has practically ceased, or the inflammation of the tissues has subsided. A single simple incision, not followed by any attemjits at draining, or at l)est by a poultice or wet antiseptic dressing, is no doubt sufficient in some cases. As a general rule, however, it does not seem advisable to rely upon this. Cases which are allowed to heal slowly are most likely to do best in the long run. In most of them the epiphora eventually passes off, or is so slight as to cause little trouble. As, however, there is a risk of recurrence at some time or other, it is a good plan after the dacryocystitis has disappeared, to slit freely either one or both canaliculi. This need only be followed by probing if there is much eitiphora. Usually the ^jassage of probes in such cases presents more difficulty than in cases of simple blennorrhoea of the sac. This is owing to loss of substance, follow^ed by fibrous stricture at the lower opening of the tear sac. In fact, it is, with possibly a few exceptions, only where there has been a dacryocystitis that any real stricture of the duct is met with naturally. But where large probes, too frequent probing, and styles have been used for ei)iphora due to blennorrhoea alone, a stricture not infrequently results. In the ])resence of a stricture, naturally or artificially produced, a certain degree of forcible probing is ])robably (piite justifiable. And here I have found conical i)robes the niost efficient. These should not, however, either be too large or passed too fre- (juently. It is often necessary, however, to continue fortnightly probings for much longer than in the treatment of simple blennorrhrea. Whether it is advisable to go on for months with this treatment or not will depend greatly upon its effect. If it keeps down the epiphora, nothing else need l)e done. * If, on the DACRYOCYSTITIS. 89 other hand, the epijAora continues to be very troublesome, or still more, if a subacute state of dacryocystitis persists or fretpiently recurs, comi)lete removal of the tear sac is un- (|ue-5tionably the most satisfactory treatment. Dacryocystitis treated in the manner just described is, with rare exceptions, either slowly recovered from without any probing being required, or only leaves a degree of epiphora, which is greatly improved or cured by the occasional use of probes. Cases of dacryocystitis which have burst spontaneously and afterwards remained untreated, are apt to be much more trouble- some. They not infrequently leave a fistula, and, it may l)e, a sort of lupoid scabbing over and round the site of the opening in the skin. They also much more frequently recur or remain chronic. In a considerable proportion of cases which have this history, removal of the sac is the best treatment to follow. An attempt should, however, first be made to treat them on the same lines as that described for cases first .seen at an earlier stage. The lupoid scar tissue, if present, should be thoroughly scraped away with a Volkmann's spoon before a free vertical incision is made into the sac. Where only a fistula without any marked infiammatiou remains, this may be treated by the actual cautery, the point of a small thermo-cautery or galvano-cautery being passed down the fistula, and the canaliculi slit. Large probes, frequent probings, and the use of styles are, in my opinion, to be avoided. Removal of the lachrymal gland, or any portion of it, which some recommend, is altogether uncalled for. The affections of the lachrymal sac and duct are of very great l)ractical importance, not only on account of their frequency, but also because of the dangers to which the eye is thereby exposed. A very large proportion of cases of one-sided blindness are cases of dense leucomata, following hypopyon ulcer of the cornea ; and that, again, is in a large percentage of cases the result of infection from a blennorrhea of the sac. A very con- siderable proportion, too, of the cases in which destructive inflammation of the corneal wound occurs after operations have the same infectious cause. CHAPTER V. DISEASES OF THE CONJUNCTIVA. The normal conjunctiva. — Very considerable ditferences exist in the appearances presented by the healthy conjunctiva. There are ditferences in vascularity, differences in the fulness and thickness of the transition fold separating the palpebral from the ocular conjunctiva, and differences in the smoothness of surface. It often happens that perfectly healthy conditions of the conjunctiva are taken for inflammatory even by those who have had considerable experience of eye diseases. This is often, as might be supposed, the case when the subjective symptoms are more or less suggestive of conjunctivitis, but the mistake may also be made even when, in the absence of any symptoms, some chance has led to an examination of the lids. The vascularity of the conjunctiva is not only subject to individual differences, but varies at different times in the same individual. The appearances presented in this respect depend upon both local and general conditions. Exjiosure to strong light, prolonged use of the eyes for reading or other work clo.se at hand, especially reading with insufhcieut illumination, cause temporary hypenemia. The same condition of course follows rubbing of the eyes, the irritation of some foreign body, dust or smoke or impure atmosphere. It is also a necessary accompani- ment of emotional disturbances which lead to weeping. Further, any cause which gives rise to congestion of the vessels of the face, such as indigestion, stooping, etc., is also followed by conjunctival congestion. In general an;vmia, on the other hand, the conjunctiva is often distinctly pale, though the exist- ing poverty in Iuemoglol)in is usually more readily .seen in the colour of the gums. The conjunctival fold, particularly that of the lower lid, is very different in different people. The difference depends in great measure upon the subconjunctival tissue. In some peoi)le the conjunctiva in this situation appears niore plentiful and is HYPER/RMTA. 91 thrown into a greater nnmber of lax folds than in others. In some, again, as the lid is everted, the fold springs into view as a more stretched and apparently less vascular covering to the mass of more or less dense and hard subjacent tissue. In most adults the surface of the conjunctiva is smooth, or there ai'e to be seen, only here and there and especially in the fold of the lower lid, small and irregularly triangular-shaped eminences— follicles. In young people, on the other hand, it is the rule to find more evidence of these prominent follicles. In many children, indeed, the follicles may be seen in consider- able numbers arranged along the ridges of the folds in the i-etro tarsal section of the conjunctiva of the lower lid, and often also at the outer and inner portions of the conjunctival mem- brane covering the upper border of the tarsus in the upper lid. Even an excessive develoimient is far from uncommon in children. Certainly those accustomed to see only the con- junctiva of adults might well imagine that the appearances then presented were pathological. In point of fact, however, this adenoid overgrowth, on account of the absence of any accompanying symptoms, as well as of its frequency, can hardly be looked upon as pathological. It is probably of the same nature as the adenoid hyperplasia which is so common in the naso-pharynx in children, and, like that, always disappears more or less completely with growth. Congestion of the conjunctiva. — When congestion of the conjunctiva persists, it must of course be considered patho- logical. This condition gives rise to symptoms which, according to its degree, to its causation, and also to individual tempera- ment, are variously described. Some complain of a hot, burning sensation in the eyes, others of a feeling as if there were sand in them. The eyes feel heavy and tired, or are weak and watering. All such symjjtoms, too, may be aggravated by exposure to light of an amount which under normal circumstances would cause no inconvenience. The causes of conjunctival congestion are both local and general. Direct irritation may be caused and kept up by noxious gases or fumes, by minute particles of iri-itating sub- stances, or by prolonged exposure to strong light. There is usually something in the occupation or habits of those who suft'er from congestion due to any such irritation, which, when inquired into, will lead more or less conclusively to the discovery of the cause. Permanent conjunctival congestion arising in this way is, however, not very common. A more important local cause of congestion of the conjunctiva 02 DISEASES OE TTTE COXTT^XCTTVA. is some error of refraction. Slight astigniatisin, hypermetropia, and less frei]uently myopia, when uncorrected, often lead to a more or less involuntary seniidosiu'e of the eyes and frowning, l)y which tlie sight is improved. This pursing up of the eyes and frowning, however, by pressure on the cornea, and esjiecially in astigmatism, where such i)ressure lias the efiect of correcting, more or less com})letely, its abnormal curvature, often leads to irritation. In most, though not all, cases where the cause of congestion is in the first jtlace an error of refraction, the symi)toms are all aggravated l)y the use f)f the eyes for near work, as it is mainly then that the unconscious effort to correct the refractive error is persisted in. Another cause of conjunctival congestion which may perhaps also be looked upon as local is the participation of the mem- brane in a liy}tenemia which has its origin in the naso-pharynx. What may be classed as the general causes of hyperaemia of the conjunctiva are probably numerous, and such as lead to both active and passive congestion — the absorption into the blood of dirterent toxins, the accumulation of uric acid and oxalates, etc. A large propoi'tion of cases of slight conjunctival congestion, in which the symj)toms complained of seem out of all p)roportion to the local circulatory changes, are of a gouty nature. Not un- frecpiently, too, hypentmia seems to be kept up in connection with constipation, and may then presumably be either active, from the irritation of absorbed toxins, or simply passive, or both combined. In all cases in which the congestion met with in the conjunc- tiva is due to general as o})posed to local causes, there are other symptoms, such as indigestion, headache, vertigo, etc., to which attention has to be directed l)efore the real cause can be estab- lished ; and although the symptoms may be aggravated l)y the use of the eyes for reading, or near work of any kind, this is not so invariably or so distinctly noticeable as in that arising in connection with refractive errors. Treatment of conjiinctlwil rovf/estio)). — In all cases where the congestion is e\'idently due to some external irritant, the treat- ment should of course mainly consist in, as far as possible, removing the cause. In addition, hot sponging and occasional bathing with a mild antiseptic — preferably a 2 per cent, solution of boracic acid — may be used. Strong antiseptics, cold com- presses or ])oultices of any kind, or astringents, must be avoided. Often, and j)articularly where the congestion has been set up or aggravated by exposure to strong light, dark (neutral-tinted) HYPERtEMIA. 93 glasses may be used out of doors, oi* at work Avheu the nature of the work entails subjection to strong illumination. Blue glasses, as they do not, although absorliing some light, sufficiently shut out the chemical (actinic) I'ays, which are the most irritating, are not so suitable. In all cases of persistent congestion the state of refraction should be examined into, and hypermetropia or astigmatism be properly corrected. ^lore especially is this advisable when there is a habit of frowning while reading. Even although an existing error of refraction may not have been the principal cause in originating the state of congestion, it may often contribute more or less towards keeping it up. Apparently even slight degrees of astigmatism, which do not appreciably lessen the visual acuity, so far at least as can be detected by the ordinary tests, may, when associated with frowning and other unconscious efforts at correction, by lid pressure, help to keep up hypersemia. Correcting glasses should therefore be used for reading. Where the presence of congestion does not receive a satis- factory explanation from any refractive error or the exposure to any external irritant, it is often accounted for, as has been said, by some derangement in general health. Attention must then be given to diet, to the action of the bowels, to exercise, etc. It is often useful to restrict the allowance of farinaceous food, and to have animal food taken finely minced, and not too much cooked. In many cases where there is other evidence of gouty irritation, some preparation of lithia, such as the citro-tartrate, taken between meals, and also colchicum, is most useful. By such therapeutic and dietetic treatment the symptoms are often very quickly overcome. Sometimes a nasal douche may be used with advantage when the conjunctival congestion is but one element of a more extensive hyperajmia — in hay-fever, for instance. The great point to bear in mind always in all cases of simple conjunctival congestion is, not to over-treat locally. Especially is it advisable to avoid astringent lotions of all kinds. The tendency to abuse in this direction is very common. Indeed, the principal cause for the {)ersistence of the congestion in many cases one sees, is in reality the treatment to which they have been subjected. Conjunctivitis. — ^When, in addition to hyperajmia, there is marked increase and alteration in the conjunctival secretions, the case must ha looked upon as an inflammation — conjunctivitis. A clinical division of the different varieties of conjunctivitis may be made, in the first place, into those which are not 04 DISEASES OF THK CONJUNCTIVA. followeil by Jiny destruction of tissue and sul)se(|uent cicatrisa- tion, and those which are complicated in this way. Of the first group, in which, after recovery, there is a complete return to the normal condition, we may distinguish two classes, accord- ing to the nature of the secretion from the inflamed conjunctiva. In the first, the secretion is muco-purulent, and there is compara- tively little or no general swelling of the lids. In the second, the discharge is decidedly jiurulent, and the inflammation of the conjunctiva is accomi)anied by considerable, often by excessive, / > •* ^^ -7 • Fiu. 34. — Showing Koch-Weeks bacilli, Ironi a case ot conjunctivitis. (xlOOO.lianis.) swelling of the lids and subconjunctival cedema — so-called chemosis. There are no doubt many varieties of muco-i)urulent con- junctivitis. There is, however, not much difference in their clinical aspects. Cases of this nature are for the most part, though i)robably not invariably, set u]) by the pathogenic action of definite and different micro-organisms. Several different microbes have been shown to cause conjunctivitis. This has been demonstrated by their constant detection in the secretion CONJUNCTIVITLS. 95 from the inflamed conjunctiva, and also by direct inoculation of the healthy conjunctiva with pure cultivations of the microbes. The main clinical differences which appear to characterise the inflammation resulting from different specific germs are — differ- ences in the severity and duration of the inflammation, and in the extent to which eczematous thickening of the skin of the lid or of the lid-margin is associated with the conjunctivitis. While, therefore, no doubt, a scientific classification of con- junctivitis cases might be based upon bacteriology, the clinical Fig. 35.— Showing Morax diplo-bacilli, from a case of conjiiiiutivitis. (xlOOOdiams.) differences are barely sufficient to be of much importance. In fact, it has been demonstrated that very different degrees of inflammation may be produced in different individuals by the same microbe. Moreover, it is not rare to find a mixed infection. The main point to bear in mind is the frequency altogether of some microhic origin. The Koch- Weeks bacilli and the pneumococci and pneumo-bacilli are perliajKS the most fre- quently met with as the causes of epidemics of conjunctivitis. The former is characterised, when uncomplicated, by the ocular 96 13ISEASES OF THE CONJUNCTIVA. conjunctiva being mainly iniiJicated, and l)y the fietpiency of small ecchymoses in this situation. Tlie Morax diplo-bacilli give rise to an acute conjunctiviti.s, which has a tendency to become chronic, but Avliich readily yields to treatment with zinc lireparations. Clinically this cause may l)e sus}>ected where a chronic conjunctivitis is associated with l)leiiliaritis and eczema coniined to the region of the outer canthus. In the ordinary nuico-purulent or catarrhal coiiJuHrtivifis there is more or less thickening of the conjunctiva, with swell- ing and increased fulness of the folds. This, with the greatly increased vascularity, gives rise to a more equable red colora- tion. An eruption of a number of very minute vesicles on the tarsal surface causes an api)earance as if the conjunctiva were strewn with sand, which, when associated with much hypenemia, gives it a velvety look. There is on the whole a tendency for the hypenumia to be confined to the i)alpebral conjunctiva. When, however, it also involves the ocular portion, it is always most marked in the perijihery, diminishing in intensity towards the corneal margin. This is a point which should specially attract attention, as, when the cornea, iris, or deeper parts of the eye are inflamed, tlie hyperaimia is, on the contrary, most intense in the circumcorneal zone, where the deeper and closer network Avhich springs from the anterior ciliary vessels is injected. An absence of any diminution of injection of the white of the eye in the neighbourhood of the cornea should always, in a case of conjunctivitis, arouse suspicion of some corneal complication. The secretion from an acutely inflamed conjunctiva is at first so preponderatingly composed of tears that it is distinctly watery. Only gradually, and after a day or two, does it assume a more viscid, and eventually more definitely muco- purulent, character. The constant overflow of tears and of the more copious and altered secretion causes excoriation of the skin. The skin surrounding the outer canthus esjiecially usually soon comes to have a raw, macerated a}»pearauce. When the eyes have been kept closed for some time, and therefore in the morning after sleeping, the lids are glued together by the retained secretion which has dried upon the eyelashes. The subjective symptoms in an ordinary acute case of muco- ]iurulent conjunctivitis are : sensitiveness to light, tiring of the eyes on reading, and a hot, burning feeling in them, which, in severe cases, and in j'fu'ticularly sensitive subjects, may even amount to more or less violent pain. The duration of an attack is very variable. The severer CONJUNCTIVITIS. 97 symptoms generally only last a few days, but may continue for weeks. As a rule, when recovery is not fairly complete in a fortnight, the treatment has been the cause of the delay. No doubt some cases have a tendency to be prolonged, altogether independent of treatment. The early recourse to astringents, such as alum and sulphate of zinc, is a very common cause of aggravation. The same may be said of poulticing, which, if continued for any time, may have, however, much worse consequences. The relief from pain which is afforded by poulticing at the beginning not un- naturally gives rise to the belief that such treatment is bene- ficial. Continued poulticing greatly increases the swelling and vascularity, and also, by favouring the growth and multiplica- tion of different germs, which are more or less constantly present in the conjunctival sac without doing harm, make these a source of danger. In addition, therefore, to the effect of one specific germ, which may cause but an unimportant reaction of no great duration, further inoculation by others of a more virulent type is apt to take place. Even iced compresses, which are so frequently recommended, more often do harm than good. This depends to a great extent upon the manner in which they are usually applied, namely, as compresses laid upon ice, and then transferred to the eye, and frequently changed. To get the proper effect from ice, which in any case should only be used at the beginning, and before the secretions have become altered and increased, the temperature of the compress must always be maintained at the freezing-point. This can be done by running iced water through a coiled tube resting on the compress. It must always be borne in mind, however, that where there is any corneal complication ice applications are dangei'ous. On the whole, there is no advantage to be gained by ice which cannot just as well be got by the efficient use of antiseptic lotions. Acute catarrhal conjunctivitis is rarely complicated by any corneal inflammation. Occasionally small superficial ulcers — " catarrhal ulcers " — form on the cornea in the course of a con- junctivitis. They occupy a position close to, but almost always a little removed from, the corneal margin. When close together, two or more may become confluent. They have a tendency, as a rule, towards rapid healing. Besides the constant blinking and photophobia from which patients with conjunctivitis sufter, they often complain of tem- porary obscuration of vision, or of seeing haloes or rings round lights, or sometimes of polyopia. All these appearances are due to little collections of secretion in front of the cornea, which 7 98 DISEASES OF THE CONJUNCTIVA. ]»rnfUicc alterations in the refraction of the rays of light enter- ing the eye. They disappear on ruljbiug the eye, but in many cases quickly reappear. The secretion from a catarrhal conjunctivitis is certainly contagious if the aflfection is acute, when it is niuco-purulent in cliaracter. In tlie more chronic forms there are j^robably consitlerable individual dirterences in this respect ; but, on the whole, the discharge in sucli cases is not by any means markedly contagious. In the treatment of conjunctivitis in the acute stage, the prin- cipal point to attend to is not to interfere too energetically. There is a danger in doing too much. All that is necessary in most cases is to freely remove the secretion during the day, and to prevent its too great retention within the conjunctival sac at night. Even those who are sutticiently alive to the disadvan- tages of an active treatment with astringent lotions, rarely seem to take care that the more suitable mildly antiseptic or other bland lotion which they employ is so used as to properly irrigate the inflamed conjunctival surface. An efficient removal of dis- charge is not got by merely squeezing a little lotion from a sponge or piece of cotton- wool into the lower conjunctival sac, or by using an eye-bath. In very many cases, however, the tendency to a speedy return to the normal in the absence of irritative treatment is so great, that this is not of much con- sequence. It certainly, however, is a better plan to irrigate properly. This may be done by allowing a pint or more of the lotion (i)referably a 2 per cent, solution of boracic acid at a temi)erature of 90° to 98° F.) to stream by gravitation over the whole surface of the conjunctiva three or four times daily. For this purpose the vessel containing the liquid may be held 10 or 12 in. above the head, and allowed to run through indiarubber tubing, to the end of which is fixed a fiatteued glass nozzle. The nozzle can be readily inserted below the upper and lower lids without touching the cornea. It is usually best to begin by everting the upper lid, and, after irrigating its tarsal surface, to insert the glass nozzle behind the ui>per margin of the tarsus, so as to get at the retro-tarsal fold. The following ointment, smeared into the eye morning and evening, will often very rapidly check a conjunctivitis : — R Zinci oxidi ...... i^ drm. Ichtliyol . . . . . . 1 gr. Fornialdeliyclc anhydr. (1 to 1000) . 5 minims. Vaselini alb. . . . . . ^ oz. In cases due to the action of the Morax diplo-bacilli, this treat- CONJUNCTIVITIS. 99 nient is practically always efficacious. In these cases the oint- ment may be used without the formaldehyde. In the more .severe and protracted cases, a daily direct ap- plication to the conjunctival surface, with a camel's-hair brush, of a strong antiseptic solution is u.seful. The most suitable are strong (fully saturated) chlorine water and nitrate of silver in a 2 i^er cent, solution. Though not always so readily got, the first is the better, and when painted over the paljiebral con- junctiva causes no pain to speak of. Corrosive sublimate solu- tions should generally be avoided ; they are more irritating and far less penetrating. The margins of the lids .should in all cases be kept smeared with some bland ointment. Fresh lard or fresh butter do very well. Vaseline is not always pure, and may cause irritation. Boracic ointment (boracic acid h drm., almond oil 20 mm., and spermaceti ointment | oz.) is probably the best. The que.stions of Ught, and of the use of the eyes for reading, etc., remain to be considered. With all inflammations of the eye itself, as well as of the conjunctiva, there is more or less photophobia, or dread of light. It does not follow, however, that the light is actually hurtful. The actinic rays are known to cause irritation of the conjunctiva, which may, indeed, as in snow-blindness and electric-light ophthalmia, be so great as to lead to %iolent inflammation. On the other hand, the same rays have been .sho\\'n to exert a powerful bactericidal effect. It is a very common treatment to keep patients suffering from conjunctivitis in a dark room. Often this is continued for weeks ; and although the discomfort which light causes is thus avoided, there is little doubt that this treatment tends to pro- long the inflammation rather than to cut it short. The patient, too, soon has his retina so adapted for the dark that even a little increase of light is painful, just as one may experience a degree of dazzling from the light of a match struck at night. The light of an ordinary room in the daytime, when the sun's rays are not pas.sing directly into it so as to be unijlea.sant to anyone else, has not any bad effect on a conjunctivitis. On the other hand, the use of dark gla.sses outside in bright weather is advisable. The open air, in the absence of i-ain or dust-clouds, is unquestionably good. This is often not properly realised ; it is jierhaps natural to suppose that there is an indication with a " cold in the eye " to remain indoors. Reading or \\Titing .should not be allowed. In acute attacks it is seldom, however, that attempts at reading are persisted in. Why reading should be hurtful is not quite evident. It is 100 DISEASES OF THE CONJUNCTIVA. certain, liowever, that it adds greatly to the discomfort caused l»y the conjunctivitis, increasing at the same time the congestion. 'IMiis discomfort, Itesides, does not })ass off on continuing reading, as does the discomfort first felt in ordinary light on coming from a darkened room. Whether as the result of inappropriate treatment or otherwise, iuHammation of the conjunctiva, instead of entirely subsiding, may continue for an indefinite time as a chronic condition. Chronic conjunctivitis is met with iu all degrees of severity, from what is little more than slight hypertemia of the con- junctiva, to a greatly thickened, fleshy-looking, pus-secreting state of that membrane, with encrustation of the lid margin ; often, too, owing to deeper infiltration, the palpebral fibres of the orbicularis fail to keep the lower lid jjroijerly in contact with the eye. The swollen conjunctiva thus becomes everted, and the excretion of tears is interfered with. The overflowing tears cause excoriation of the skin, and the ectrojnon once .set \\\) becomes more and more marked as time goes on. The everted conjunctiva, besides being thickened, is also hardened, as the result of constant exposure to the air, and may even be encrusted or covered by scales or .scabs. These very bad cases of chronic conjunctivitis are mostly met with in old people ; they are not the cases one is most frequently called upon to treat. In all cases in which conjunctivitis has become chronic, the first points to be ascertained, before any line of treatment is begun, are the nature of the external surroundings and of the treatment which has already been adoi)ted. Where the patient is constantly subjected to smoky or hot and close atmosphere, or to any evident source of irritation, such conditions should, as far as po.ssible, be removed. If he has been poulticing, or, what comes to the same thing, keeping moist applications to the eye, or tying it up and allowing the bandage to become moistened by tears, or if strong astringent lotions have been used, such treatment should at once be discontinued. It is generally well, too, to look to the state of the mucous membrane of the naso-pharynx, as a chronic catarrh in this situation is apt to keep up a con- junctivitis, even although it may not have been the jirincipal cause in originating it. Still more important in this respect is the state of the tear .sac. Inflammation of the mucous mem- brane lining the tear duct and sac is sometimes complicated by conjunctivitis, which may be set up by inoculation from this source. On the other hand, even severe purulent primary in- flammation of the conjunctiva seldom, if ever, spreads to the CONJUNCT! VITTS. 101 tear sac. A proper treatment of the inflammatory condition of the naso-pharynx is often useful, in addition to anything which may be undertaken for the more direct treatment of the con- junctivitis. But treatment of the sac for a coexisting blen- norrhoea is an absolute necessity. Without an improvement in this situation no treatment of the conjunctivitis alone can be of much avail. In the least severe cases of chronic conjunctivitis, in which there is little or no thickening of the conjunctiva, and not much increase in the secretions, it is not generally necessary, if the precautions referred to as to surroundings be taken, to do any- thing very active. It is mainly in respect to their origin, namely, a preceding acute attack, that they differ at all from cases of conjunctival congestion. They should therefore be treated much in the same way. Change of air, especially to some dry, high- lying inland place, may be tried, and any existing error of re- fraction should be corrected. In addition, a weak astringent may sometimes be useful, such as solutions of hazeline, tannic acid, myrrh, alum, or ichthyol. The following are prescriptions which may be recommended for this purpose : — 1^ Hazelmi 4 oz. Aqua^ carui .... 8 „ R Acidi tannici .... 6-12 grs Sodre. biboratis .... 3 drms. Glycerini ..... Aquaiii camphora? ad 6 ,, 12 oz. T^ Tinctura? myrrhre Aqu?e destillata' 2 drms. 12 oz. R Ahiniinis 10-20 gi-s Aqupe rosfe .... 12 oz. ^ Ichthyoli .... Aqufie sambuci Aqiiiie destillatre, Tui . h drm. 6 oz. In more severe cases, with thickening of the conjunctiva, swelling of the folds and deeper infiltration, as evidenced by slight ptosis, and with more or less distinct muco-purulent secretion, there is, I believe, nothing better than lead. A solution of the neutral subacetate of lead, in the strength of 1 grs. to the ounce of water, may be painted directly over the mucous surface of the everted lids once daily, and an irrigation of boracic acid made twice or thrice daily, or a wash of the san^e lead salt in weaker 102 DISEASES OE THE CONJUNCTIVA. solution (^-1 gr. to the ounce) may be used about three or four times in the twenty-four hours. In the worst cases, painting with strong chlorine water or a '2 per cent, solution of nitrate of silver once daily, is useful in addition to the lead wash. Where there is ectropion of the lower lid, the lower canaliculus should be slit with a Weber's knife. The scales must also be removed from the lid margin, and an ointment of iodoform and vaseline (1 to 7) smeared on the raw surface. Owing to the frequency of foUiculosis in young people, it often happens that the ajjiiearance of the conjunctiva presented in an ordinary muco-purulent inHammation is such as to suggest some different and specific type of conjunctivitis. The overgrow^th of adenoid tissue may be so marked a feature, that the follicles appear as numerous papillae in the swollen and congested membrane. When this is the case, it is not uncommon to hear the con- junctivitis spoken of as a follicular conjunctivitis. It is not improbable that the same ii'ritation which causes the conjunctiva to inflame may give rise to some further follicular enlargement, but, as far as the inflammation goes, both in its causation and course, it is a simple con- junctivitis. The treatment should be in every way the same as that already described. Special care is, however, required in irrigating, as the presence of the many elevations makes it more ditficult to thoroughly remove the secretions. The treatment of cases of conjunctivitis with marginal ulcera- tion of the cornea .should be the same in most resi)ects as that already described. Lead lotions must, however, be avoided, as they cause dense white deposits in the cicatrices, which remain after the ulcers have healed. Where the ulcers are superficial and small, a drop or two of a weak nitrate of silver solution (1 gr. to the ounce) may be drop})ed into the eye, after an irriga- tion with boracic lotion, once daily for three or four days. This often at once induces healing, even in cases where the ulcers have Fio. 36. — Conjiinetivitis with marked swelling of the follicles caused by atropine irritation. CONJUNCTIVITIS. 103 continued in much the same state previously for a couple of weeks or longer. The ulcers often cause a good deal of pain. To allay this, cocaine may be used (a 2 to 5 per cent, solution of hydrochlorate) ; but it is not advisable to apply it very frequently — for instance, every half-hour, as is often done. Immediately before and after each irrigation is sufficient to give relief. It is a good plan, too, to drop a few drops into the eye the last thing at night, as the local anaesthesia thus caused often allows the patient to fall asleep, which the pain otherwise prevents. Eseriue drops are often recommended for the treatment of catarrlial as well as for other forms of corneal ulcer. I have never been able to satisfy myself that they are of any use at all for this purpose ; and as they are sometimes actually hurtful, they should not be used. Dark glasses are particularly indicated in all cases of conjunctivitis with marginal corneal ulceration. Deeper and more rapidly extending marginal ulcers should be brushed once or twice with chlorine water (full strength), or, if this is not available, with a 2 per cent, solution of nitrate of silver. The brushing, to be effectual, should be done with some force, the camel's hair being dabbed on to the ulcers several times, so as to bring the antiseptic properly in contact with all parts of their surface. By using cocaine this can be done with- out causing any pain to speak of. Afterwards, dusting with finely-powdered iodoform is useful after each irrigation. The application of iodoform in powder is preferable to its use either in ointment or in gelatin discs, the latter of which dissolve in a few minutes and leave only a comparatively small quantity of the iodoform in situ. When deeper marginal corneal ulcerations exist, in the absence of much conjunctival secretion it is some- times a good plan, if they do not tend to heal, to cover them with a flap of conjunctiva. This is done by undermining the surrounding conjunctiva with scissors and stitching it forwards. Spring catarrh.. — A peculiar variety of recurrent chronic conjunctivitis has received the name of spring catarrh. This is a rather rare affection, met with in young individuals, and char- acterised by an injection and swelling, limited to the circuni- corneal portion of the ocular conjunctiva. The elevations which are met with in this situation, and which either extend all round the cornea, or are limited to some portions of its margin, are solid greyish milky-looking masses, which show no tendency to ulcerate. In this resi)ect, as well as on account of their solidity, they are readily distinguished from phlyctenules, which they at first sight sometimes resemble. Associated with this affection there is, also, a more or less characteristic milky-white coloration of the 104 DISEASES OF THE CONJUNCTIVA. conjunctiva as a wliole. In some cases the condition is accom- panied 1)}' some increase in the secretions. Sliglit infiltration of the corneal margin may occur — never, however, extending far in ; and, beyond a sometimes high degree of i)hoto})hol)ia, the affec- tion does not give rise to any symj^toms of consequence. Not unfrequently flattened masses of cartilaginous-looking granula- tion tissue make their ai)pearance on the surface of the tarsal portion of the conjunctiva of the upper lid. These may attain an enormous size, and such cases are liable to be mistaken for trachoma. The inflammation has, more than other forms of conjunctivitis, a tendency to recur every spring, and to continue, when once set up, for several months. In many cases the im- provement which takes place at the beginning of the winter apjiears not to go on to complete recovery, so that the condition in spring may be looked upon more as an exacerbation than as a true recurrence. Sj^ring catarrh is in reality a hyperplasia of the epithelium alone ; there is no deep infiltration. Treatment. — Astringent lotions should be avoided. If there is much photophobia, dark glasses may be used. Excision of the granulations when they are massive, or, still better, bm-ning them down carefully with the thermo-cautery, is the best treat- ment. No cicatrix need be left if this is properly done. Purulent conjunctivitis. — Although an acute attack of simple conjunctivitis is often accompanied by considerable purulent discharge, it is nevertheless important, from a clinical point of view, to make a distinction between this and the more characteristically purulent forms of inflammation, namely, gonor- rhceal conjunctivitis and the conjunctivitis of new-born infants, ophthalmia neonatorum. Gonorrhoeal conjunctivitis, or gonorrhreal ophthalmia, is one of the most serious inflammations met with in the eye. It is set up usually by the direct transference of pus from a gonor- rhoea into the conjunctival sac. Such pus is now known to acquire its virulence from the presence of cjonococci. The first symptoms begin several hours, or it may be as late as a day or two, after inoculation. The appearance during the first day may be such as to suggest merely an acute attack of simple conjunctivitis. More frequently the rapidity with which the sym})toms set in, and especially the early appearance of more or less chemosis, excites suspicion, and leads to the detection of the source of inflammation. The pus finds its way to the eye from a urethral or vaginal gonorrhcea, or from a similar inflammation in some other eye, so that the inoculation may either be from the individual himself, or from some one else whose towel has PUPtULENT CONJUNCTIVITIS. 105 been soiled by the discharge, and used subsequently Ijy the patient. The great importance of warning patients suffering from gonorrlicea of the danger to their own eyes, and those of others living in the same room, of using towels, sponges, etc., in common, and of the consequent necessity of absolute cleanliness, cannot be exaggerated. Considerable differences exist in the length of time before the inflammation reaches its full height and leads to a copious purulent discharge. What is usually distinguished as the first stage, in which there is only a watery and slightly mucoid discharge, often considerable in amount, may last a couple of days or more, or may rapidly pass on to chemosis, due to a fibrino-plastic exudation beneath the conjunctiva, and to swelling and redness of the lid. The second stage, which is characterised by the purulent discharge in addition to the chemosis and swelling of the lid, may then be reached on the second day after the first symptoms have made their appearance, or may be delayed, and this is more common, till the third or fourth day, or even later. The difterence in the rapidity of development has been shown to stand in close connection with the amount of active inoculating matter wliich enters the eye. Small amount, dilution, and desiccation all retard the onset as well as the rapidity with which the abnormal changes succeed each other. Yet the resulting inflammation may be, and most frequently is, just as violent as that which results from inoculation with a more copious, and, at the time, a more virulent secretion. This fact is of practical importance, in so far as it indicates the possibility of checking the disease in some cases by timely anti- septic measures. Besides the appearances described as characterising the first stage of gonorrhoeal ophthalmia, more or less pronounced sub- jective symptoms — pain, burning and neuralgic in character, photophobia, and lachrymation — are constant, and increase as the tenseness of the swelling of the conjunctiva and lid be- comes greater and greatei-. The swelling of the upper lid generally reaches such a degree as to cause it to hang down over the lower lid, and to assume a red glossy appearance on its surface. It is then perfectly impossible for the patient to open his eye, or even for the lid to l)e raised to any extent with the finger. The full height of the inflammation generally continues for from one to three days, after which the skin of the lids regains some of its natural wrinkling, and the circulation in tlie conjunctiva becomes freer. The discharge continiies as copious 106 DISEASES OF THE CONJUNCTIVA. as before, but less ftocculent, and the conjunctiva becomes redder and softer. The hardness, caused by the .serous and often fibrino-plastic subconjunctival effusion during the course of the inflammation, is a source of danger to the cornea, whose nutrition, derived as it is from the surrounding vessels, is thereby more or less interfered with. It is not uncommon to find, therefore, a steaminess or loss of transparency of the cornea, which at the time of examination may or may not be associated with ulcera- tion. Tliis ulceration is often near the margin of the cornea, and is then hidden by overlapping portions of chemosed con- junctiva ; it has a tendency to extend, not only in depth, but also circumferentially. When extension takes place in the latter direction, the result is apt to be a necrosis of the whole central portion of the cornea, and a consequent hopeless destruction of vision. A complication with corneal ulceration may also be met with at a later stage of the disease, during the period of retrogression. The ulcers then formed have not unlikely quite a ditiereut etiology and are more amenable to treatment, and consequently less likely to lead to total destruction of the cornea. They are usually due to the inoculation of the corneal tissue with the pus from the conjunctiva. As long as the conjunctival discharge continues, there is the possibility of a complication of this nature, although the danger diminishes every day. On this account it is important to avoid any rough handling during the treatment of the lids, as any abrasion of the cornea very much increases the risk of inoculation. Most likely corneal affections met with at any stage of the conjunctival inflamma- tion are, properly speaking, infective. While, howevei-, the later ones are only liable to make their appearance where the cornea is abraded, the more serious early ulcerations may be accounted for by sup[)Osing that there is first a maceration of and interference with the vitality of the superficial layers, and subsequently, inoculation. In acute cases, complete recovery of the conjunctival inflammation, and a return to the normal condition without any loss of substance, takes place in from three to six weeks. Some cases gradually lapse into a chronic state. In these cases the conjunctiva often remains enormously swollen for months, the tarsal portion assuming a thick and more or less uniform velvety appearance, while the retrotarsal folds present large fleshy elevations and furrows, which protrude into prominences when the lids are everted. Not unfrequently this leads to ectrojnoii. The lower lid is more often everted, on account of the smaller PURULENT CONJUNCTIVITIS. 107 size of the tarsus, and the thickening of the skin produced by excoriation of the overflowing tears and secretion. Occasionally, however, the upper lid is everted as well, the everted portion being often hardened and encrusted if not properly attended to. While in all conditions the cornea is liable to ulceration from inoculation, the more serious, and, properly speaking, necrotic form is less liable to make its appearance, or at all events to show the same tendency to circumferential extension in cases where a previous abnormal vascularity has existed. This cir- cumstance is taken advantage of in the treatment by inoculation of cases of dense superficial vascular keratitis or ])annus. (See p. 152.) Having regard to the grave consequences to the coi'nea which a purulent conjunctivitis may entail, the treatment has to be con- sidered not only from the point of view of what is best for the infected eye, but also with regard to prophylaxis in the case of the other eye. Indeed, the first thing which should always be done, whenever there is cause to diagnose a gonorrhoeal or other purulent conjunctivitis of the one eye, is to actively disinfect the other, and then secure it against the risk of subsequent infection — a risk which, it must be remembered, exists so long as the purulent discharge continues. The disinfecting of the sound eye is of course undertaken on the supposition that it may possibly have been recently inoculated, and may be done in the following way : After drop^nng a little cocaine solution into the conjunctival sac, the lids are everted, and the mucous surfaces, including as far as possible the folds, painted over with chlorine water. The lid margins are then rubbed freely with little pledgets of absorbent cotton-wool moistened in the same antiseptic. This is followed by a free irrigation of the whole conjunctival sac, with not less than a pint of a 2 per cent, boracic acid solution. A little iodoform or boracic ointment is lastly rubbed along the lid margins and the occlusion dressing applied. It is advisable to adopt some arrangement whereby sufficient l)rotection is provided against inoculation, while at the same time the good eye is not altogether thrown out of use. The simplest and most readily prepared contrivance for this purpose is what is known as BuUer's shield. This consists of an ordinary watch- glass fixed in an aperture between two pieces of adhesive plaster so that three margins of its under surface can be readily fixed along the forehead, down the side of the cheek, and along the nose. The lower edge is not plastered to the face. This allows the air to get in behind the shield and prevents dimming the glass. lOS DISEASES OF THE CONJUNCTIVA. In applying the shield the watch-glass should be secured in a suitable position in front of the eye, and particular care should be taken that the margin along the nose adheres tightly. An I'xtra strij) of ))laster may with advantage be fixed over this margin. The advantage of Buller's shield over a regular occlu- sion l)andage is not confined to the relative comfort which the patient o))tain.s. An additional advantage is, that it docs not as Fio. 37.— BuIUt's shield. a rule require to be changed, as it admits of a ready insjiection of the eye by the surgeon. In the treatment of the inflamed eye everything must be done which is calculated to prevent the cornea becoming involved. It is well to recognise that the main, if not the only, cause of an accompanying corneal ulceration is an inoculation with the specific discharge in places from which the protecting epithelial surface has l)een removed. The denuded cornea is certainly easily inocu- lated. Possibly inoculation may take place even when the epithelial covering remains intact. It certainly does not do so so PURULENT CONJUNCTIVITIS. 109 readily, and therefore from a clinical point of view it is well to keep before one the desirability of providing as far as possible for the protection of the epithelium. Careful handling is therefore a most necessary precaution. Removal of epithelium is too often caused by forcible opening of the swollen lids. Owing to the pain and swelling of the lids, it is no doubt often difficult to get a })roper view of the eye without using some force. Perhaps the best plan is to droj) a few drops of a solution of cocaine (2 to 5 per cent.) into the eye, and then separate the lids by the finger tips a})plied to their margins, taking care not to allow the nails to scrapie on the cornea. Indeed, the use of the cocaine should be as much to facilitate gentle handling as to diminish the pain which an examination causes the patient. This is often forgotten, yet it Ls of great importance. Cocaine should only be used during any manipulations which the treatment renders necessary, not at other times. Elevators or a speculum should in general be avoided, and when introduced, and whilst in situ, must be kept held away from the cornea, so that the epithelium may not be injured in any movement of the eye. Strong caustic solutions are also liable to injure the corneal epithelium when applied to the conjunctiva. Those most commonly in use are solutions of nitrate of silver and corrosive sublimate. The former should not be used on this account stronger than 2 per cent., or 10 grs. to the oz., and the latter not more than 0"0002 per cent., or about 1 gr. to 10 oz. But it is better to avoid these solutions altogether. Inoculation, the result of corneal abrasion, may occur at any part of the cornea. The treatment is veiy often to blame when an ulcer occurs in a central portion of the cornea, as it has then certainly been preceded by an abrasion which has been more or less preventible. It is otherwise with the more frequent marginal ulceration, the existence of which is often first evidenced by a cloudy opacity passing into the cornea in some particular direc- tion. The ulcer itself at its beginning is not unfrequently covered by the overlapping chemosed conjunctiva of the glolje. Such ulcers originate from inoculation by discharge which is l)ent up between the chemosed conjunctiva and the corneal margin. Whether the discharge in this position leads to a localised loss of corneal epithelium from maceration, and only then effects an inoculation, or whether the more ju-olonged contact of the virulent matter overcomes the resistance of the epithelium, is a point of no practical im}>ortance. The practical consideration is really the necessity for preventing any stagna- tion of the secretion in this situation. There are two ways in no DISEASES OF THE CONJUNCTIVA. wliich this indication may be complied with — first, by irrigation, and secondh', by excision of tlie conjunctiva immediately sur- rounding the cornea. Irrigation with boracic lotion, as already described, is sufficient where the chemosis is slight. When the conjunctiva overlaps the cornea, however, as a tense and swollen membrane, it is undoubtedly safer not to rely upon irrigation alone, but to freely remove witli a pair of scissors the overlapj)ing zone, so that the corneal margin in its entirety is exposed and readily kept clean. This is a much more efficient treatment than that often recommended, of making radial incisions in the cliemotic conjunctiva. Such incisions, by reducing the swelling, diminish the tenseness of the overlapping, and therefore to some extent fulfil the same indication ; but it is better, when interfering at all surgically, to perform a regular peritomy. In addition to frequent irrigations, the conjunctiva covering the lids may be painted twice daily with chlorine water. The patient should be allowed to be out in the open air and sunlight as much as possible. A little boracic or iodoform ointment may be smeared along the edges of the lids at night to prevent retention of the secretions. When the cornea does suffer, efforts to check the progress of the ixlceration are mostly unsuccessful. A touch on the surface of the ulcer with a camel's-hair brush difjped in chlorine water, followed by dusting on of finely powdered iodoform, may be tried. Ophthalmia neonatorum is practically the same disease as that just described ; that is to say, it is clue to an inoculation with a sjjecific virus. The virus is probably not always the same, or at all events, what may be specifically the same, has suffered some modification, as there are greater differences met with in the intensity of this form of infiammation than can well be accounted for by merely individual receptive difterences on the part of the jtatients. Inoculation of the eyes of infants takes place in two ways — either directly from the maternal passages during birth, or afterwards by the use of soiled linen, s^jonges, etc. In the first case the infiannnation usually begins on the third day, although it may be delayed two or three days longer, and both eyes, as a rule, are affected. In the second case the first appearances are often later in presenting themselves, and not so frequently in both eyes simultaneously. Purulent inflammation beginning after the first week is almost certainly due to some extraneous source of inoculation. The liability to purulent conjunctivitis in the new-born infant is greater the more prolonged the birth. PURULENT CONJUNCTIVITIS. Ill Ophthalmia neonatorum is not by any means as a rule so severe an inflammation as purulent conjunctivitis in the adult. In the great majority of cases it is mainly the palpebral con- junctiva which is affected, so that the cornea does not run the same danger. The corneal complications which do arise are mostly the result of unskilful handling and want of cleanliness ; that is to say, they are of the directly infected type, and can often be arrested by proper treatment. It is seldom that one feels so helpless with respect to them as is the case with the early ulcerations in gonorrhoeal ophthalmia. Nevertheless, ophthalmia neonatorum is an extremely danger- ous inflammation, and one which too often results in more or less complete destruction of sight. The treatment has to be considered both from the point of view of jjrophylaxis as well as from that of cure (to use a popular expression), when the inflammation has been established. The prophylactic treatment has been followed by the most conspicuous success, so that from this cause alone a very great diminu- tion in the number of cases of early blindness has resulted. It is, consequently, unmistakably the duty of every medical practi- tioner who is in the habit of attending confinements, as well as of midwives, not to neglect such pi'ophylaxis in any case where there appears to be the least necessity for it. Inoculation can practically, almost ahvays, be counteracted by the following treatment : — As soon as the child is born, the eyes are wiped carefully with a little cotton-wool which has been dipped in freshly boiled water at a temperature of 100° F. Care is then taken that the Avater used for the bath does not come in contact with the eyes. Imme- diately after the general cleansing, the eyes should be well washed with the boiled water trickled into them from absorbent wool as the lids are held apart. They are then thoroughly dried, and a drop or two of a 2 per cent, solution of nitrate of silver dropped into each conjunctival sac. This is the method of Crede. It is certainly at once the simplest and the most efficient prophylactic treatment. It is, no doul>t, also a good plan to make use of antiseptic douching of the vagina before birth. This may i^revent an inoculation taking place at all, but does not do away with the necessity for the treatment of the child's eyes in the way just described. Inoculation may take ^ilace also before birth. It is extremely rare to meet with an already developed purulent conjunctivitis at birth, and in such cases there can be no question of pro^jhy- 1 1 2 DISEASES OF THE CONJUNCTIVA. laxis. C)n tlie other liand, the mother or nurse shoukl be warned of tlie jtossibility of hite infection through want of cleanliness. The treatment to be adopted in ophthalmia neonatorum should be much on the same lines as that for purulent conjunctivitis in adults. An occlusion bandage is unnecessary for the one eye, as even in the comparatively few cases in which only the one eye is affected (mostly cases of inoculation after birth) it is not easy to keep it proi)erly ai)plied. Incision or circumcision of the ocular conjunctiva is also inadvisable. It is rare that the chemosis is as excessive as in the adult, and besides, it is well to avoid loss of blood in infants. Irrigation should be made fi'equently and carefully, always bearing in mind the risk of any corneal abrasion. The painting of the everted lids with chlorine water may be done twice a day ; and later on, when the lids are lax and the swelling has subsided but the secretion from the con- junctiva is nevertheless copious, a daily brushing with a 2 per cent, solution of nitrate of silver may be substituted for the chlorine water. It should be remembered that even when the cornea becomes imi)licated the prognosis is relatively much more favourable than in adults. The tissue changes are moi-e active and rajiid, so that the cicatricial tissue may become in the course of time rej)laced by clear corneal connective tissue. When no perforation has taken place, the prognosis is good. With perforation, on the other hand, much will depend upon its extent and site, as well as upon whether or not it is accompanied or followed by altera- tions in the shai)e of the cornea. When there is only a partial staphyloma it is well to perform iridectomy early. In a good many cases of ophthalmia neonatorum the conjunc- tival surfaces of the lids are found to be covered by a membrane. This form of membranous conjunctivitis must be distinguished from di]:)htheritic conjunctivitis. The membrane is easily de- tached, and although there is a tendency towards bleeding fi'om the conjunctiva when it is rubbed off, it can readily be seen not to be due to any intimate adherence between the membrane and the conjunctiva, such as characterises dii)htheritic inflammation. The abundance of the purulent secretion, as well as the absence of the livid grey coloration and marked constitutional disturb- ance, also distinguish this form from the much more uncommon diphtheritic conjunctivitis. Coagulation of the secretion from an inflamed conjunctiva seems to take place in a proportion of cases, resulting from all, or almost all, causes of irritation. Thus the irritant may be a foreign body lodged in the conjunctival folds, or a chemical irritant, or an eczema, or some of the cocci PHLYCTENULAP. CONJUNCTTVITTS. 113 and bacilli which are known to lead to conjunctivitis. Further, the membrane may vary greatly in its character, from quite a thin pellucid pellicle, which can be floated off the conjunctival surface by a gentle stream of liquid, to a pretty dense and fairly adherent coagulation, which to separate from the conjunctiva requires some degree of rubbing or traction, and which when removed leaves a raw and bleeding surface. In the treatment of membranous cases, of whatever causation, the application of caustic solutions should be avoided. Phlyctenular conjunctivitis. — A very common variety of conjunctival inflammation is one in which the congestion is less diffused. It is mainly the ocular conjunctiva which is Fig. 38. — Phlyctemilar coiijiinctiviti.s. affected, and that in more or less definitely circumscribed areas. These areas of congestion may be at any part. They are met with in single patches, or distributed more or less all over the white of the eye. Very often the mid-point of a congested patch lies on or near the corneo-scleral margin. The main characteristic, however, of this variety of conjunctivitis, and that which gives to it the name " phlyctenular," is the presence of little blebs on the surface of the congested portions of con- junctiva. These blebs vary considerably in size. Many of them are so small as to be only recognisable on close inspection. Very commonly they have a diameter of 1 mm. Occasionally they are met with three or four times this size. The larger ones 114 DISEASES OF THE CONJUNCTIVA. arc usually seen as collapsed buihe, sometimes as regular pustules when their liquid contents have become inirulent. At a later stage, when the epithelial covering has been shed, they are converted into small superficial ulcers, and eventually heal with- out leaving any visible changes. Two })oints in connection with phlyctenular conjunctivitis call for consideration as matters of practical importance. In the first place, the condition is always indicative of some constitu- tional delicacy. Again, more or less serious complications on the part of the cornea are to be feared. Corneal complications, however, are in this case of a difi'erent nature from those which have been referred to as existing in other forms of conjunctivitis. Fio. 39.— Pustular conjunctivitis. They are apparently not auto-infections caused by the specific action of the secretion from the inflamed conjunctiva. Indeed, altogether in this afi'ectiou, when uncomplicated, the conjunc- tival secretions are not markedly altered, although no doubt there is frequently an increase in the watery constituent — a more or less pronounced degree of lachrymatiou. Clinically, this difference in the connection existing between the conjunctival and corneal inflammation in jjhlyctenular, as compared with other varieties of conjunctivitis, is important. It is most probable, indeed, that phlyctenular conjunctival and corneal inflammation has a microbic origin, just as other forms of conjunctivitis have. Certain investigations seem to show that such is the case. Yet even if it be so, there is here not PHLYCTENULAR CONJUNCTIVITIS. 115 so much a question of the risk of contagion of a healthy cornea from contact with an altered conjunctival secretion, as of the existence of a suitable soil for the development of more or less characteristic corneal changes from the same cause as the specific conjunctivitis. The indications for treatment are therefore of a different nature. The corneal changes so often occurring along with phlyctenular conjunctivitis are essentially superficial. They are met with as single or multiple superficial infiltrations of varying size. These infiltrations are often, though not invariably, vascularised. They leave corresponding opacities, so-called neJndce, only the most sui^erficial and least extensive of which may subsequently clear up. These nebulie, according to their size and density and site, interfere with vision by causing irregularities of the surface of the cornea, and by scattering, instead of properly refracting, the light-rays which pass through them into the eye. Phlyctenular conjunctivitis and keratitis are mostly met with in children, and have a tendency to recur at intervals for a number of years. In many cases there is considerable, often very great, dread of light — photophobia. This leads to a more or less convulsive closing of the lids,— blepharospasm, — a con- dition which not only complicates, but actually aggravates and jirolongs the local inflammation. Sometimes, indeed, though rarely, the strong pressure of the spasmodically closed lids on the eyes produces great lowering of the intra-ocular tension, and may lead to serious interference with nutrition. When phlyctenular conjunctivitis, with or without its attend- ant superficial keratitis, is met with in adults, it is mostly in individuals who have suffered from the same form of inflam- mation in childhood. It comparatively rarely occurs for the first time after puberty. Treatment must be both local and general. The local treat- ment should not be confined to the use of measures which are calculated to have a direct influence on the conjunctival and corneal inflammation. It is often a matter of quite as great importance to give special attention to the treatment of such an aggravating complication as blepharospasm. In old-standing cases, too, it may be necessary to do something to relieve the lid pressure on the eyes which results from narrowing of the lid apertures. Often, again, there is an associated blepharitis, which calls for treatment at the same time. Further, the condition of refraction should always be examined into, and if necessary corrected, in the case of patients who, after recovery from an attack, are old enough to be able to read. 110 DISEASES OF THE C'OX.TITNCTIVA. With regard to local applications, it is iiiii)ortant to remember that astringent lotions of all kinds are not generally well toler- ated. The eyes should, however, be kept clean by being bathed several times daily with boiled water, or boracic acid lotion. Tying-up of the eye, so often practised in these cases, is decidedly hurtful. It not only increases the tendency to blei)liarospasni, but very often virtually amounts to ]toulticiug, as the bandage soon gets saturated by the tears, which are always more copious than under normal conditions. !Many substances have been used in the form of ointment applied directly to the eye. The most useful, however, is the yellow oxide of mercury. This substance has the properties of a stimulant and antiseptic combined, and in the class of cases under consideration is, more than any other, practically a specific. Other jjreparations of mercury are no doubt also useful. The yellow oxide, however, is the only one that may reasonably be regarded as a specific in phlyctenular inflammation. It is generally used in the form of ointment, in the strength of 8 to 20 grs. to the ounce. As such, it goes by the name of Pagen- stecher's ointment. The yellow oxide may be mixed with different bland ointments. The following preparation can be recommended : — B Hydrargyri oxidi flavi .... 4 grs. Olei amygdallaris ..... 20 minims. Ung. cetacei (sine benzoinn) . . . 4 oz. This should be applied once in the tw^enty-four hours, and pre- ferably at night. A piece about the size of a split pea is inserted between the lids at the outer can thus. The lids are then rubbed gently over the eye, so as to combine a kind of local massage with the spreading of the ointment. This massage seems to be of some importance in increasing the efficacy of the application. In order to be able to do it properly, it is often advisable to drop a drop or two of a 2 per cent, solution of cocaine into the eye a few minutes before using the ointment. Any blunt, smooth, clean instrument does for introducing the yellow oxide ointment — a glass rod is perhaps the best. The lids are separated with the forefinger and thumb of the left hand, while the end of the rod, with the ointment adhering, is placed between them. Then with the same fingers the lids are pressed together, and made to wipe off the ointment as the rod is withdrawn. Before any of the Pagenstecher ointment is used, it is im- portant to see that it has been properly prepared. A little, BLEPHAROSPASM. 1 1 7 removed on a glass rod, should for this purpose be examined with an ordinary magnifying glass. If any little gritty particles are then seen, the ointment is unsuitable, and will cause too much irritation. This precaution is often neglected, and the irritation produced by wrongly-prepared yellow oxide ointment is one of the reasons why many ophthalmic surgeons, and with- out doubt to the disadvantage of their patients, do not use the ointment at all. Another point which is often forgotten is that, valuable as the yellow oxide ointment is in the real phlycteimlar type of superficial corneal inflammation, it is useless or hurtful in many other inflammations of the cornea. Even in the phlyctenular cases it is not as a rule so well tolerated by adults as by children. Consequently it is well to begin by using it not so strong, and afterwards increase the strength if it causes no marked irritation. As a general rule the hypersemia, and accompanying sensation of pain or burning in the eye, does not last longer than from five to fifteen minutes after the use of the ointment. In any case in which they are more prolonged, the ointment should be considered irritating, and be weakened or discontinued. The yellow oxide application should be made so soon as any characteristic phlyctenules appear on the conjunctiva, and should be continued for a month, or longer, after they have completely disappeared. There is little doubt that, by doing so, relapses, and especially corneal complications, can often be prevented. As recurrences are apt to take place in children, who are especially liable to this form of inflammation, the parents should be instructed to have recourse to the treatment as soon as the phlyctenules show themselves. The ointment should of course be freshly and properly prepared each time. Attention should also be directed in all chronic cases to the condition of the naso-pharynx, which will often be found to call for treatment. Often such treatment will have a more or less marked influence on the conjunctival affection. Blepharospasm, which originates reflexly as the result of an irritation of the superficial sensory nerve-twigs of the cornea, and in consequence of the curious photophobia which this irritation produces, often becomes so intense as to call for special treatment. The blei)harospasm is most violent in children. It stands in no evident relation to the severity of the corneal mischief, though it is no doubt frequently aggravated by in- judicious treatment. It is, for instance, encouraged rather than relieved by keeping the children in the dark, as is so often done, and still more so by bandaging the eyes. It is also bad to 118 DISEASES OF THE CONJUNCTIVA. allow the little patients to be constantly liolding in front of, and actually pressing into, their eyes a handkerchief or cloth, which soon becomes moistened by tears, and which, in the case of ill- tended children, usually is allowed to become dirty as ^vell. Often children sutiering in this way are over-coddled and spoilt by too much sympathy, and by being carried about instead of being allowed to walk. All this favours the convulsive closure of the eyes. After some time, too, the difficulty of opening the eyes is increased by excoriations of the skin whicli the tears cause, princi[)ally at the outer canthus. The tirst thing to do is to try to break the bad habit which such treatment has fostered. For this purpose cocaine in a 2 per cent, solution may be freely dropped into the eyes several times a day. The patients may be allowed to wear a brown paper shade covering both eyes. They should, however, be prevented as far as possible from constantly mopping or holding any cloth in front of their eyes. They should not be carried, but allowed to find their own way about, both in the house and outside, where, except in very bad weather, they should be kept as much as 2)0ssible. Often, if these different })oiuts are properly attended to, the })hotoi)hobia may become less pronounced, and the blepharospasm checked. In a numljer of cases something more, however, is required to get rid of the blepharospasm. In young children up to 4 years of age a good plan is to plunge the head into cold water, holding it there until the child begins to gasp for breath. This causes a shock whicli makes the child open its eyes, and when it has done so once or twice it afterwards becomes easier under natural conditions. In older children, forcible opening of the eyes, and dilatation of the lid aperture, is useful. This is best done by means of elevators introduced below the upper and lower lids, and pulled apart wdth some force. Cocaine may be first dropped into the eyes, and an existing excoriation of the skin at the outer canthus may be lightly touched with a piece of caustic. The forcible dilatation may sometimes be repeated several times, at a day or two's interval, with advantage. This is, however, seldom necessary. In bad cases, in which no improvement follows one dilatation, it is better to sever the fibres of the orbicularis at the outer canthus with a pair of strong, straight, l)lunt-pointed scissors. To do this, one Jalade of the scissors is passed into the conjunctival sac, and })ushed as far outwards in a line with the lid a])erture as it will go. The scissors are then tirndy closed, so as to cut through all the tissues from skin to conjunctiva. The bleeding is usually pretty free, but is readily CANTHOPLASTY. 119 stopped by pressure or torsion. The cuts are then allowed to heal without being stitched. In cases in wdiicli there have been repeated attacks of phlyctenular inflammation, and the lid apertures have become permanently contracted, a very great improvement may be got by the operation of canthojylasty. The first step in this operation is the same as that just described for cutting across the orbicularis fibres. The wound is, however, not allowed to FlQ. -10.— Showing position of sutures in tlie operation of uauthoplasty. After Wecker. heal as it is, but the opening made is rendered permanent by transplanting conjunctiva into it. To do this, a sj)ring speculum is introduced below the lids as soon as the scissor-cut has been made. A stitch is then passed through the mid-point of the severed conjunctiva, and carried out through the skin at the apex of the wound. On knotting this, the conjunctiva is forcibly drawn to the outer end of the incision. Two other stitches should then be applied, one above and one below, by which the conjunctiva is further drawn to the upper and lower edges of 120 DISEASES OF THE CONJUNCTIVA. the .skin wound. Care must be taken that in all these stitches the raw surface of^the conjunctiva is brought into contact with the raw surface of the .skin, and that no fold of conjunctiva is caught in the suture. No dressing need be ajiplied, and the stitches may be removed after three or four days. Where a similar operation is indicated in cases where the conjunctiva has undergone degenerative changes, and can there- fore not be transplanted in this manner, the aperture may be kept ojien by transplanting .skin. An operation of this kind, which gives very good result.s, was first recommended by Kuhnt. A flai) of skin, the shape of which is shown in Fig. 41, is cut from the ui)per or lower lid. The base of this flap, one quarter Fig. 41.— After Kuhnt. of an inch or so in breadth, should have its centre in a line with the lid aperture. The flap should contain nothing but skin. After it has been cut, the enlargement of the aperture may be made with the scissors in the manner just desci'ibed. The con- junctiva is then undermined for a .short distance. After this has been done, the skin flap is turned into the wound, and its end in.serted below the conjunctiva, while the edges of the skin, from which the flap has been cut, ai'e brought together by sutures. An antiseptic dressing is then applied, and left un- changed for two or three days. It is best not to put any stitches into the skin fiajj, but merely push it under the con- junctiva for some distance, to leave room for shrinkage. It PHLYCTENULAR CONJUNCTIVITIS. 121 gradually assumes more and more of the character of mucous membrane. With regard to the general treatment of patients suffering from phlyctenular conjunctivitis and keratitis, it is important to remember that the condition always indicates some lowered state of vitality. In a large jiroportion of cases there is found to be a more or less pronounced strumous diathesis. The cervical glands, for instance, are very frequently enlarged. Apart from such diathesis, and still more where it does exist, the first attack of the characteristic inflammation is often seen to follow recovery from measles or whooping-cough. Attention must in all cases be given to diet, which should be generous. In poor, ill-fed, and ill-tended children, in whom phlyctenular inflammation is most prevalent, great improvement often at once follows their admission to hospital, and that altogether independent of any special treatment — merely as the result of better feeding. In all cases cod-liver oil, alone or com- liined with malt in some form, is of great use. It is, in point of fact, to many both food and medicine. Syrup of the iodide of iron may also be given with advantage. Proper regard to the condition of the skin is very essential. A daily bath should be given, and clean underclothing worn. Children suffering from phlyctenular inflammation are, as a rule, benefited by being sent to high-lying places inland. Their state is often aggravated, on the other hand, by residence near the sea, though this is far from being invariably the case. Not only on account of the eye trouble itself, but also owing to the local manifestations indicating a constitutional weakness, it is advisable to discourage schooling. The importance of this is apt to be overlooked, especially amongst the working classes. There is not only the dread of interference on the part of the local School Board with which one may have to contend in trying to get parents to keep their children from school for a sufficiently long time, there is, besides, the real inconvenience which keeping an older child at home often entails on mothers who have younger ones to attend to in addition to their house- hold work. Often, however, when these difficulties are par- ticularly pressing in the case of poor town children, there may be found relatives in the country to whom they can be sent, or, failing this, it may be possible to gain admission for them into some suitable Convalescent Home. Inasmuch as phlyctenular inflammation is one of the most fruitful sources of more or less serious permanent defect of sight, it is of the utmost importance that careful attention 122 DISEASES OF THE CONJUXCTIVA. should everywhere be given to its treatment, both local and general. Diphtheritic conjunctivitis may exist alone, or along with diphtheria of the throat. In the latter case it would appear that the conjunctival inflammation is generally the first to make its a})i)earance. This affection is very rare in Scotland, though met with pretty frequently in some countries, es2)ecially North Germany. In London, too, it is not infrequent. Stei)henson, for instance, has found it in fully 1 })er cent, of the cases attending the out-patient departments of the London Children's Hospitals. The inflammation begins with hypera^mia and lachrymation, just as in sim^ile catarrh, and in the severer cases rajjidly pro- ceeds to great swelling of the lids and chemosis, as in purulent conjunctivitis. The infiltration of the lids leads to greater stiffness and pain than in iiurulent conjunctivitis. A greyish- yellow membrane is not long in making its appearance on the palpebral conjunctiva, and may also involve the ocular con- junctiva. The false membrane may cover only a portion of the surface of the conjunctiva, or may be found in patches over the surface. These patches sometimes become more confluent, and such cases are the most severe. The membrane cannot be completely removed without leaving a raw bleeding surface, which itself has not the natural healthy appearance, but presents that of a fibrinously infiltrated tissue. The discharge, to begin with, is less in quantity and much thinner than in jjurulent conjunctivitis, though it often afterwards becomes more copious and purulent. There is danger for the cornea throughout, but the risk is greatest during the first few days. The cornea may be lost, as the result of a kind of necrotic and diphtheritic process combined. Ulcerations occurring at later stages are not so likely to lead to total destruction of the cornea. They are more superficial and more allied to phlyctenular or eczematous ulcers. Constitu- tional symijtoms, fever, and })ronounced lassitude are met Avith in a much more marked degree than in other forms of conjunc- tivitis, but the affection rarely jn-oves fatal unless there is at the same time a throat comi)lication. Di})htheritic conjunctivitis api)ears to be most common in young children. Only about 1 per cent, of the cases are met with after the age of four years. The sexes are e({ually aftected. Tn all cases of true conjunctival diphtheria the exciting cause is the Klebs-Loffler bacillus. This microbe is capable of setting up a conjunctivitis which in ditt'erent cases exhibits all degrees DIPHTHERITIC CONJUNCTIVITIS. 123 of severity, from what is only a tritiing intlamniation, barely distinguishable, if at all, from the milder forms of catarrhal con- junctivitis, to the characteristic severe disease which leads to destruction of the conjunctiva and subsequent cicatrisation. The reasons for this difference in sevei'ity are probably various. There may be differences in susceptibility, in the virulence of the germs, and as regards the presence or absence simultaneously of other pathogenetic organisms. The coexistence of phlyctenular inflammation, in any case, appears to favour the specific action of the Loffler bacillus, and so lead to the severer forms of diphtheria. Although it is comj^aratively rare to find the fauces attacked, it is not so uncommon to meet with a true diphtheria of the surrounding skin, especially that of the eyelids. Most frequently only one eye is affected, and in the severer cases there is always swelling of the preauricular glands. A condition very similar to severe diphtheritic conjunctivitis, and, it may be, clinically indistinguishable from it, is sometimes caused by a streptococcus infection. There is reason to believe that this infection may be conveyed to the eye by flies or other insects. In the treatment of conjunctival diphtheria there are two [loints which equally require consideration, namely, the local treatment and the general (antitoxin) treatment. Locally applied antiseptics must be directed against the specific bacillus and other microbes which may be associated with it. For this purpose removal of the membranes, and applications of chlorine water, freely painted on the conjunctival surface with a large camel's-hair brush, may be used twice daily. In addition, it is well to irrigate the eye thoroughly from time to time with a milder antiseptic, or simply with boiled water at a temperature of 100" F. Antitoxin injections up to 4000 units should be made in all severe cases, as well as in all milder cases in which bacteriological examination has shown the ^jresence of the Luffier bacillus. Trachoma is a specific and essentially chronic form of in- flammation of the conjunctiva. It is characterised by a kind of hypertrophy of the mucous membrane, which is eventually always followed by atrophy and cicatrisation. The hyjjertrophy assumes both the papillary and the follicular type. In some cases throughout, and at certain times in the course of other cases, the one type is found to predominate. Papillary hypertrophy occurs on the tarsal surfaces, and mainly in the upper lid. It does not differ in appearance from that met with in other affections of the conjunctiva in which the 1:^4 DISEASES OF THE CONJUNCTIVA. ]>a])ilhe undergo enlargement, such as in chronic blennorrlioea and ectroi)ion. The difference lies solely in the subseciuent connective tissue development, degeneration, and cicatrisation. The cause of this inherent difference has not yet received a satisfactory explanation. The follicular hypertro})hy in trachoma mainly implicates the conjunctiva of the retrotarsal folds. In this situation there may be seen, always some and often numerous, approximately s2)herical, grey, translucent bodies. They are visible through the superficial layers of the conjunctiva, the surface of which is rendered uneven by the way in which they protrude forwards. Where the papillary overgrowth is not too great they may also be seen in the tarsal conjunctiva, where they always appear to be smaller and more yellowish in colour. These are the so-called trachoma f/ranules. They do not very markedly differ in appearance from the follicular masses which are seen in follicu- losis of the conjunctiva in young people. In contradistinction to what is met with in that condition, however, the true trachoma granules are always present in greatest numbers in the ui)[)er lid. Whilst too, in the case of folliculosis, they become absorbed in the course of time without leaving any appreciable trace, in trachoma their disappearance is associated with cica- tricial changes, which in the long run may amount to complete destruction of the mucous membrane. It follow's that while the true nature of the conjunctival hyper- trophy in trachoma becomes easily recognisable in the later cicatricial stages, some doubt as to diagnosis is at least possible to begin with. It must be admitted, however, that some practised observers deny that the diagnosis of trachoma ever l>resents any difficulty from the first. Trachoma occurs in an acute form accompanied by all the subjective symptoms of conjunctivitis, also by a distinctly purulent secretion. It is much more frequently nowadays met with as a chi'onic process, which until it leads to interference with vision, owing to corneal complications, may give rise to so little inconvenience as to be actually unsuspected by the in- dividual affected. Not unfrequently acute exacerbations, accom- panied as a rule by the formation of fresh granules, occur in the course of a chronic trachoma. The cornea may suffer in two different ways : from /lannn)^ and ulceration. Pannus is the most frequent complication. It is met with at some stage of the trachomatous process in most cases. Where there has only been a slight degree of conjunctival hypertrophy, TRACHO^IA. 125 followed by early retrogression, pannus is not likely to occur, although it may immediately make its appearance along with a fresh attack in the lids. The clinical appearance of pannus is that of a superficial vascularised infiltration, spreading usually over the upper jiart of the cornea to begin with, and start- ing from the corneo-scleral margin. Great difi"erences occur, according to the density, extent, and vascularity of this in- filtration. It may in some cases be so great as to be quite fieshy looking. Pannus is essentially a trachoma of the cornea, and consists of a cellular infiltration, with new-formed vessels, below the corneal epithelium. If it has not existed long, it is capable of absori^tion, aud the cornea then regains its transparence. When the condition has been of long duration, however, the cellular infiltration has penetrated deeper through Bowman's membrane and undergone cicatricial changes, destroying at the same time more or less of the true corneal connective tissue, and thus leading to permanent opacity. There is nothing particularly characteristic about a tracho- matous ulcer. It may or may not occur in a part of the cornea afi'ected by pannus. In any case it leaves, on healing, a per- manent intransparency. In long-standing cases of trachoma the tarsus itself becomes infiltrated, and subsequently undergoes a similar cicatricial change to that of the conjunctiva. This leads to trichiasis and entropion, and the inverted eyelashes, by injuring the corneal epithelium, pave the way for ulceration. A certain amount of ptosis is very generally met with as an accompaniment of trachoma. This is probably due to a com- bined paretic condition of the unstriped muscular fibres which are inserted into the upper margin of the tarsus, caused by in- filtration, and the increased weight of the thickened lid. The frequency of trachoma varies very much in different districts and communities. It is mostly met with in low marshy countries, and in places where the population is crowded, ill- fed, and under altogether unfavourable hygienic conditions. In foreign towns the Jewish, and in our own the Irish, quarters present the largest percentage of trachoma. In Scotland it is a rare affection except amongst the Irish population. Prisons and barracks too are, and more especially have been, visited by epidemics of it. Armies, particularly in the East, have been visited by the same disease, which, as general attention was first given to it on accoimt of Larrey's description of the state of the eyes of the French array in Egypt in 1798, is often called 126 DISEASES OF TTIE CONJUNCTIVA. Etiyptutn nphthdlmin. Egyptian ophthalmia inchidcs, however, many otlier forms of conjunctival tlisea.se besides trachoma. Trachoma is sj»read by contagion. The reason why it is most prevalent, wherever there is over-crowding, is that then the con- ditions under which contagion is most likely to take place, such as the use of towels, sponges, etc., in common, are most favourable. The con- tagious matter is the secretion. Consequently cases in which the secretion is copious are the most likely to spread the disease, though the same secretion is found not to produce ecjually acute attacks of trachoma in all in- dividuals. It is now pretty well established that infection does not pass by the air, as was at one time supposed. In the treatment of trachoma, attention must be given to cleanliness and ventilation. It is certainly inadvisable to allow anyone with this disease to sleep in the same room with others, or to use towels or sponges in common with anyone else. He should be well fed and kept as much as possible in the open air. In the acute form of the inflammation it is inadvisable, as a rule, to use astringents ; at most, and only as long as the cornea is unaftected, a weak solution of subacetate of lead (2 grs. to the ounce), painted on the everted lids once daily, and boracic acid lotion as a wash, may be em- ployed. When on the supervention of catarrhal inflammation there is a good deal of muco- purulent discharge, nitrate of silver solution, preferably Aveak (5 grs. to the ounce), may be cautiously applied to the everted lids. For the chronic cases there is certainly nothing better than bluestone. This should be applied daily to the everted lids, taking care to get the crystal (which should be smooth) well at the retrotarsal fold. Some cases do not tolerate sulphate of copper ; and, in such, touching with a smooth piece of alum, or painting wdth the solution of lead, may be used instead. I have no experience of the treat- ment with jequirity, which is sometimes used. Undoubtedly the treatment of many cases of trachoma may be greatly expedited by certain operative measures Those I eULL SIZE Fig. 42. — Knapp's roller forceps. TRACHOMA. 127 have found most useful are expression of the follicles with Knapp's roller forceps (Fig. 42), and grattage with Janiieson's files (Fig. 43). The roller forceps are suitable to begin the treatment with in all cases where the trachoma granules are })resent in considerable numbers. The method of proceeding is as follows : The patient is anaesthetised. The lid is then everted, and one roller end of the forceps is introduced and pointed as far up as possible into the transition angle beyond the retrotarsal fold, while the other roller rests on the tarsal surface close up to the lid margin. The rollers are then firmly approximated, and the forceps drawn forcibly towards the everted upper end of the tarsal conjunctiva until they drag their way free. This is repeated for different parts of the conjunctiva ; and, finally, different folds of the lax retrotarsal portion of the conjunctiva are included between the rollers and given an additional squeeze. The patient is then put to bed, and iced compresses applied for some time to allay Fig. 43. — Dr. Chalmers Janiieson's rasp. the irritation which is produced, which, notwithstanding the somewhat rough nature of the operation, is seldom great. Grattage is most suitable for cases in w^hich the lids are much thickened and the papillary swelling pronounced. It can be done under cocaine, the files being freely rubbed backwards and forwards over the tarsal conjunctiva. This has to be repeated many times at intervals of a few days, and gradually effects a reduction of the swelling. Sometimes it may advantageously be combined with the use of the roller forceps. Attempts have also been made to cure the more persistent cases of trachoma by excising altogether portions of the con- junctiva in which the granulations are most abundant. This treatment is much practised in Konigsberg, where the disease is of frequent occurrence, and is strongly recommended by Jacobsou. Sattler, too, who has had a large experience of the treatment by excising the conjunctival fold, speaks well of it, although he mostly gives preference to a treatment which con- sists of rupturing the follicles with a cataract needle, and scoop- ing out their contents with a fine circular sharp spoon, 2 to 4 mm. in diameter. 12S DISEASES OF THE CONJUNXTIYA. Tlio ac'companying pannus does not call for special treatment, having a tendency to inii)rove or disai)i)ear with tlie cure of the conjunctival iiiHannnation. Amyloid degeneration of the conjunctiva. — This is a rare disease, clinically distinct from, though apparently having some connection with, trachoma. The appearance presented is that of yellowish and waxy-looking masses on the pali)ebral conjunctiva of both upper and lower lids, springing from the retrotarsal fold. The masses are usually very hard, and there is at the same time always a great eidargement of the tarsus. Portions excised give the characteristic reaction of amyloid degeneration. The exact nature of the process is differently described by various histolo- gists. There seems little doubt, however, that the jtrocess is entirely a local one, as it is rarely, if ever, associated with similar degeneration elsewhere. The treatment recommended is the excision of the waxy masses along with the tarsus. Essential shrinking of the conjunctiva. — Occasionally, and without any marked inflammatory symptoms at the time, an atrophy of the conjunctiva, or a complete growing together of its opposed surfaces, takes place. A connection between this degenerative change and pemphigus has been pretty certainly established. Cases of pemphigus of the conjunctiva are met with in which the eruption on the conjunctiva forms part merely of a more or less generally distributed skin affection of the same nature. Several cases of essential shrinking have come under my own observation, but I have only once seen the disease accompanied by pemphigus. The treatment has been always without any effect, even where transplantation of mucous membrane from other parts has been tried. Ecchymosis. — Any rupture or incision of the conjunctiva, pro- duced either accidentally or by some operation, gives rise to effusion of blood into the membrane, which, according to its extent, takes from one to three weeks to undergo absorption. Spontaneous ecchymoses occur by the bursting of conjunctival vessels, usually owing to some excessive strain which has caused temporary congestion of the head — coughing, sneezing, vomiting, etc. A tendency to the occurrence of such ecchymoses indicates often a degenerated state of the vessels, and may therefore be of symptomatic importance. Emphysema of the conjunctiva may occur alone or along with ecchymosis. In the latter case, some connection has been estab- lished between the air passages and the orbital tissues. The condition is rare. PTERYGIUM. 12U Pterygium. — An inflammatory or hypertrophic thickening of a portion of the conjunctiva, of a triangular shape, firmly attached lay its apex to the superficial layers of the cornea, has i-eceived the name of pterygium, owing to its fancied resemblance to the wing of an insect. The sides of a pterygium form distinct folds, under which a probe may be passed, often for a considerable distance. The folding-in of the sides gives an appearance as if some new membrane lay over the conjunctiva. Very consider- able differences exist in the consistency of the pterygium. In some cases it is thin, pale, and fibrous ; whilst the other extreme is represented by a sw'ollen, red, fleshy elevation of the charac- tei'istic triangular form. ''•'"jn'^n^^^ Fig. 44. — Pterygium. The ordinary pterygium is always found in a position corre- sponding to the palpebral fissure, and therefore over one of the lateral recti muscles ; much most commonly over the internus. Sometimes it exists in both eyes, and occasionally two are met with in the same eye. Pterygium has a tendency in most cases to spread over the cornea, though it is rarely seen to extend beyond the centre of the pupil. It occurs only in individuals who are exposed to constant irritation of the conjunctiva, and in whom, at the same time, the conjunctiva is tolerably lax. It is therefore most frequently found in masons, field labourers, colliers, etc., and generally after the age of forty. The irritation to which they 9 130 DISEASES OF THE CONJUNCTIVA. are subjected causes, in all urobability, not only hypertrophy of those portions of the ocular conjunctiva which are not covered by the lids, but a loss of the normal epitlielial covering, so that there is a tendency for an adhesion to take place between the conjunctiva and the epithelial surface of the contiguous cornea, the vitality of which is also interfered with from the same cause. After such an adhesion has once taken place, the continuance of the irritation causes the surface of the conjunctiva to double over more and more on the cornea, and thus to extend its attachment with the superficial layers of the cornea, and at the same time drag more and more on the surrounding conjunctiva. A less common form, or what may be called a spurious pteri/ffium, is met with at any part of the conjunctiva. It is the result of the attachment of a portion of chemotic conjunctiva to a sub- jacent ulcer of the cornea. Such cases only develop after severe intlammations, and do not extend. They also, as a rule, leave a complete space, which is bridged over, so that a probe may be passed from side to side below the fold of conjunctiva. The treatment to be adopted in the case of pterygium should depend upon w^hether or not it is progressing in such a manner as to interfere with vision or with the free mobility of the eye. If this be the case, or if for the sake of appearance the patient wishes it to be removed, an operation should be performed. The most suitable and satisfactory method of operating is the follow- ing : The pterygium is seized with a pair of forceps held in the one hand, and the portion adherent to the cornea carefully dis- sected off with a small bistoury or Sichel's knife. When this is done, an incision is made from the cornea-scleral margin at the upper edge of the pterygium with a pair of straight scissors, in the direction of and extending to the centre of its base. A similar snip is made from the lower margin of the pterygium at the border of the cornea, meeting the first at a point. In this manner a lozenge-shaped piece is removed. Then there remains a raw surface in the conjunctiva, which is to be covered by undermining the conjunctiva above and below, and drawing it together wdth stitches. When this is propei'ly done, it is rare to meet with any recurrence. It is essential, however, in order to ensure success, that the patient should not be exposed to the same irritation to which the original occurrence of the affection is to be ascribed, until some time after complete healing has taken place. When possible, it is advisable that he should change his occupation altogether for one which does not entail the same risk. In cases where, although there can be no doubt as to the gradual progression of the pterygium, the patient is nevertheless INJURIES. 131 unwilling to submit to operative interference, he must be pro- tected against the constant irritation in some manner best suited to the requirements of each case. If he continues his usual occupation the eye should be tied up for a lengthened period. The spurious form shows no tendency to progress, and never recurs after operation. Pinguecula. — Another change met with in the ocular con- junctiva of adults — sometimes, though not always, as the result of continued irritation from some cause or other — is what is called Pinguecula. This is a whitish or pale yellow condensation of the conjunctival tissues covering the sclera, mostly to the inner and outer sides of the cornea, and corresponding, therefore, to that portion which lies opposite the palpebral fissure. The patch is often irregularly triangular in shape, and generally only very slightly prominent. Most commonly it is met with to the inner and outer side in the same or in both eyes, but more pro- nounced, as a rule, to the inner side. It does not cause any inconvenience, and does not call for operation. Pinguecula is a slow inflammatory thickening of the deeper tissues of the con- junctiva, which, although yellow in appearance, does not contain fat. Injuries to the conjunctiva — Foreign bodies in the con- junctiva. — Clean cuts in the conjunctiva readily heal without giving rise to inflammatory reaction if the edges of the wound are brought together by stitches. Left to themselves, such wounds are apt to gape, so that healing takes place by granula- tion, and is therefore often accompanied by more or less con- junctivitis. Foreign bodies when retained in the conjunctival sac for days or weeks set up a traumatic conjunctivitis. They usually lodge somewhere under the upper lid, and mostly become fixed, with or without penetration, in some portion of the con- junctiva covering the tarsus, often close to the lid margin. Sometimes they become embedded in the folds of the retrotarsal portion of the conjunctiva, or owing to suction — as, for instance, in the case of husks of corn — lie with the concave surface against the conjunctiva. In the first position they are apt to give rise to ulceration of the cornea. Owing to this circum- stance, it is well to make a practice of always everting the lids, and of carefully examining the conjunctival surfaces in all cases of inflammation of the conjunctiva, or of abrasion or ulceration of the cornea. Portions of glass are the most difficult to detect, so that when there is any suspicion of there being a foreign body of this nature present, the everted lid should be examined with oblique illumination, and, if necessary, with a magnifying glass. 132 DISEASES OF THE CONJUNCTIVA. Besides the cutting and contusion which may be caused by mechanical injury to the conjunctiva, and tlie subsequent changes, intlammation and cicatrisation, wliich result in tl}is way, other and often more serious changes are caused by agents which have a chemical or thermal action. Accidents from the introduction into the eye of acids, alkalies, lime, boiling water, or molten metal are not uncommon. As a rule such accidents are immediately followed by great pain, which leads the patient to seek advice as soon as possible. When, as usually lia})})ens, a portion of the conjunctiva has been destroyed, the prognosis will depend greatly on the extent as well as position of the injured i)ortion. Except whei-e the cornea is .seriously damaged at the same time, the worst cases are those in which a considerable extent of both ocular and jialpebral conjunctiva has been destroyed, and more especially when the destruction has involved the retrotarsal fold. It becomes, then, impossible to prevent adhesion of the lid to the globe, or what is called symblepliaron. A symblepharon necessarily, too, gives rise to more or less restriction of the movements of the eye. It is often possible to remedy the defect by some operation ; but it is of great importance to make an effort, in all cases .seen soon after the accident, to avoid the formation of an adhesion between the two raw .surfaces. This can, as a rule, be .successfully accomplished, if the fold of transition from the ocular to the palpebral conjunctiva is not injured to any great extent, by frequently dropping a few drops of almond oil into the eye after washing it out with a weak non-irritating antiseptic lotion, and at the same time frequently separating the two surfaces. This treatment should, in any case, be adopted immediately after an injury has been received which is likely to cause destruction of the conjunctiva ; but it must, of course, always be preceded by a thorough examination of the whole extent of the conjunctival surface, and the removal of any foreign bodies. Foreign bodies of various kinds — dust, engine sparks, etc. — fre- quently remain adherent to the palpebral conjunctiva of the upper lid. The usual site for such foreign bodies to occupy is the conjunctival surface covering the tarsus, especially the portion of it which lies near the free lid margin. These can readily be removed by everting the lid. Attempts at removing them without eversion, with a camel's-liair brush, or the tip of the tongue i)assed below the ui)per lid, should not be made. When the suspected foreign body is not found on the tarsal surface, the fold itself must be properly inspected. This is often neglected. It is most readily done, by anyone not sutticiently SNOW-BLINDNESS. 133 practised to do it with the fingers alone, by pressing a probe down on the skin of the lid, whilst it is held everted, and while the patient rotates his eye downwards as far as possible. Electric light ophthalmia.— Amongst those whose eyes are subjected to the glare of a powerful arc light, an intense con- junctival irritation is sometimes found to come on several hours afterwards. The condition is exceedingly painful, accompanied by swelling of the lids and great photophobia. It has been shown by Widmark, by a series of beautiful experiments, that it is the violet and ultra-violet rays contained in the electric light which cause the characteristic irritation. Snow-blindness. — Both as regards its symptoms and etiology, Fir,. 45. — Lymphangiectasis of the conjunctiva. snow-blindness is closely allied to the form of conjunctival irritation set up by exposure to strong electric light. There is intense photophobia, swelling of the lids and chemosis, following upon the exposure for some hours to the light reflected from snow. As in the case of electric light ophthalmia, it is the irri- tation of the conjunctiva by the shorter, moi'e actinic waves of light which gives rise to these symptoms. Dark smoked glasses should be used as a protection wherever there is the risk of either electric-light or snow-blindness. Lymphangiectasis of the conjunctiva. — A not uncommon appearance is met with in the conjunctiva, as the result probal)ly of some interference with the normal flow of the lymjjh, and conseL^ueut dilatation of the lymph spaces. This change, which 134 DISEASES OF THE CONJUNCTIVA. seems to be of no importance, and not associated with any inflammation, consists in the formation of blebs of clear straw- coloured liquid, not bigger tlian a i)in's-head, but crowded together in masses. The blebs are situated in the sui)erficial layers of tlie conjunctiva, so that they can be readily pushed with the conjunctiva over the su]>jacent tissues (see Fig. 45). They often disappear spontaneously after some weeks or months. Tumours and other aflfections of the conjunctiva. — Tumours of the conjunctiva are rare. Of the non-malignant forms l)erhaps the most common are papillomata. They usually occur as multiple excrescences from the conjunctiva, at the inner angle of the eye in the region of the caruncle, but are found at the same time springing from the palpebral conjunctiva. Their surfaces are generally uneven, often crenated, but they may also be smooth. If thoroughly removed, there seem.s to be no tendency to recurrence. Simple enlargement of the caruncle is sometimes met with. Dermoid cysts of the con- junctiva are mostly situated at the corneo-scleral margin, and involve the cornea as well. Of malignant tumours sar- comata of the conjunctiva are not so very uncommon. They are most free|uently met with in the ocular conjunctiva. They may or may not be melanotic. Even when ap})arently very completely removed, they are extremely liable to recur. When, therefore, no doubt exists as to their nature, — as, for instance, when they are melanotic, and when in catching hold of them Avith the fixation forceps they readily break and bleed, and show themselves to be of a soft buttery consistence, — the best treatment, unless the other eye should be blind or absent, is to remove the eye, and at the same time a part or all of the contents of the orbit. Rodent idcers and epitheliomata are generally found as exten- sions from the skin of the lids, but they may originate in the conjunctiva. They must in any case be freely removed. Tuberculous and lupoid sweUinys of the conjunctiva occur Fig. 46. -Case of dermoid cyst of conjunctiva. TUMOURS. 135 as rare affections, the lattei* mostly spreading from the skin, while the former appear to originate in the conjunctiva. They both have a tendency to spread to the cornea. The differential diagnosis is by no means easy. Tubercle bacilli Fig. 47. — Case of melauoid sarcoma of the coujunctiva. have been found in some cases. The ti'eatnient consists in excising or thoroughly scraping away the soft tumour tissue. Chancres occur occasionally in the conjunctiva, and involve the skin of the surrounding lids. They are not, as a rule, diffi- cult to diagnose, but any doubt is set at rest by the appearance of secondary symptoms in a certain proportion of all cases. CHAPTER VI. DISEASES OF THE CORNEA AND SCLERA. General Remarks on Inflammation of the Cornea. The corneal tissue may be the site of inflammatory products, deriving their origin from a focus of inflammation which is situated either in the cornea itself, or in some other part of the eye. In the first case we may talk of a 2>rimary or true l^eratitis ; in the second, there is, properly speaking, no keratitis, but merely a more or less dense, difi^use infiltration of the cornea, similar in every way to the hypertemic and edematous area of infiltra- tion which surrounds a focus of inflammation in any other part of the body. The condition is one, then, of secondary diffuse in- filtration of the cornea ; secondary as distinguished from a similar infiltration surrounding a primary inflammation of the cornea. Primary keratitis, except when confined to the epithelial layer, is mostly associated with some degree of destruction of the corneal tissue at the focus of inflammation, and the loss thus sustained is rejjlaced by more or less intransparent connective tissue. It occurs in two forms — as an infiltration, and as an ulceration ; that is to say, the inflammatory changes are either surrounded by more or less healthy tissue, or have led to a destruction of the superficial layers of the cornea, so that there is an open sore. It is customary to distinguish between primary infiltration and abscess of the cornea. The latter is said to exist when the infiltration is purulent and destruction of the tissues has taken l)lace. It is not always possible to make this distinction clinically. The colour of a corneal infiltration depends so much on the depth at which it lies, as well as on its density, that if one were to judge by colour alone, one would frequently diagnose an abscess when such did not exist in the anatomical sense. The degree of pain is also a very uncertain sym[)tom, as great difl'erences exist in this respect, KERATITIS. 137 Clinically, then, we may divide primary corneal inflammation into ulcerative and non-ulcerative. The non-ulcerative frequently becomes eventually ulcerative. Both forms may be single or midtij^le, according as one or more foci of inflammation are present. They may be superficial or deep, diffuse or circum- scribed, vascularised or non-vascularised, and may or may not be complicated by inflammation or other changes of any other part of the eye, .such as iriti.s, scleritis, or any alterations in the contents of the aqueous chamber, such as the presence of pus (hypopyon) or blood (hyphsema). Fig. 48. — Case showing extensive superficial vascularisation and ulceration of the cornea. An irregularly shaped central portion remains clear. When healing takes place, the margin of an ulcer becomes rounded all over, owing to the extension over it of an epithelial covering, and the less of substance is gradually rei:)aired by the development of an intransparent connective tissue. There is thus left an opalescent or white opacity, a so-called macula or nelnda of the cornea, as the result of the cicatrisation. An exceedingly dense white cicatrix is called a leucoma. An ulcer which extends in depth may lead to perforation of the cornea. This may give rise to further complications, the nature of which depends on the .situation and extent of the perforation. If small and central, there may be no further 138 DISEASES OF THE CORNEA AND SCLERA. complication tlian the emptying of the anterior chamber, whereby the lens comes in contact witli the posterior surface of the cornea. When the lens remains long in this position there is ajit to be set up a proliferation of the cells lining its anterior capsule, leading to what is called anteru/r caiimdar or ityramidal cataract. When the central perforation is large, the lens, and even more or less of the vitreous humour, may be expelled through it. Sometimes a perforation at the centre of the cornea remains for a long time open, constituting what is called •AjiMula of the coniea. When a perforation occurs more towards the margin of the cornea, it is the iris which, on the escape of the aqueous humour, Fig. 49. — Anterior synechia. becomes applied to the posterior sm'face of the cornea. The most favourable result which may follow this accident is for the iris to go back into its pi'oper jjosition on the re-establishment of the anterior chamber. This hajjpens if the perforation is small and rapidly closed. The portion of the anterior surface of the iris, which at the time of perforation becomes pressed up against the back of the cornea, may form a permanent fibrinous adhesion in this situation, and thus give rise to Avhat is called an antericn- synechia (see Fig. 49). There is then more or less interference with the free movement of the pupil, which, as it dilates less in one or more directions than in others, loses its circular form and becomes irregular in shape, usually oval or egg-shaped. In the case of larger perforations, the iris is entangled in the corneal STAPHYLOMA. 139 opening, and more or less of it may protrude or prolapse exter- nally. The iris usually then becomes incorporated in the cicatrix. To this condition the name of leiicoma adherens is given. Corneal ulceration, when extensive or deep, leads also to alteration in the curvature of the cornea. Such an alteration may or may not be accompanied by more or less marked pro- trusion of the cicatrised portion, or what is called staphyloma of the cornea. A corneal staphyloma may be partial or complete, according as only a portion or the whole of the cornea is in- volved in the protrusion (see Figs. 50 and 53). The most severe cases of corneal destruction are followed by disappearance of the cornea — phthisis corneas. Not infrequently a corneal in- flammation is associated with, or leads to, inflam- mation of the iris. The principal caiises of 2)rimary keratitis are traumata, either with or without subsequent sepsis, struma, and ex- tension of conjunctival in- flammations. The homo- geneous elastic layer of Descemet, which, along with its layer of epi- thelium, bounds the true corneal tissue posteriorly, does not undergo inflam- matory change. When perforation takes place after there has been an ulcerative destruction extending through the whole depth of the superficial layers, it is owing to the bursting of this membrane, which may for some time previously have been protruded into the ulcer, giving rise to the condition known as heratocele. After perforation there is usually observed a great tendency to healing. The various diseases of the cornea are in all respects the most imjiortant of the common diseases of the eye. They are for the most part cases in which not a little good can be done by proi^er and judicious treatment, and in which much harm may result from wrong interference or neglect. Their importance lies in this, coupled with the value to vision of the normal cornea. There are other parts of the eye which are of course equally Fig. 50. — Case of staphyloma involving a large portion of the cornea. 140 1)I8EASE8 OF THE CORNEA AND SCLERA. valuable in this respect, but of few of them can it be said with equal justice that the treatment is often of great importance in influencing the consequences of the diseases by which they may be affected. The main dangers to which the cornea is exposed by inflam- mation are, as we have seen, more or less serious permanent loss of transi)arency, and alterations in its curvature. Any collection of inflammatory products within the meshes of the corneal con- nective tissue causes an intranspareucy, and this, according to cir- cumstances, may or may not be permanent. When there is no actual destruction of corneal tissue to account for some, at all events, of the inflammatory products, there need be, and gener- ally there is, no jjermanent opacity left in the cornea. A localised inflammatory destruction, however, anywhere, is followed by cicatricial tissue formation, and this is always in- transparent. In infants and young children, in whom the tissue changes are active, even cicatricial opacities may clear. This, however, takes place very slowly, as the connective tissue of the cicatrix gi-adually becomes replaced by corneal connective tissue. The points in this connection which are of practical import- ance, then, with respect to both prognosis and treatment, are the recognition of interstitial infiltration opacities from cicatricial opacities, and the influence of the patient's age in the stability of the latter. Both forms of opacity may exist together. That is to say, we may find at some stage in the healing process an area of the cornea in which the opacity is due to cicatrisation, sur- I'ounded by one often considerably more extensive, in which the cause is merely an infiltration. It frequently hajDpens too, that, owing to the latter obscuring more or less of the impillary portion of the cornea, vision is much more interfered with than it eventually is, after all jjossible absorption has taken place. The surrounding infiltration can generally be recognised by its less pronounced Avhiteness and density. Further, its margins merge indefinitely into the clear cornea, never ending sharply, as does a cicatricial opacity. The surface of the cornea, the epithelium, is often irregular over the cicatricial opacity — never so, or at least only finely stippled, where the cause of the dulness is mere infiltration. Although it is common to talk of opacities in the cornea from cicatrisation and infiltration, the loss of transparency does not in reality ever lead to real opacity. The tissues remain translucent, and it should be remembered that translucent nebula? or leuco- mata in the cornea may interfere with vision, not only by ex- cluding more or less of the light rays which should enter the ULCERS. Ul pupil to form the retinal image, but also by scattering those which they intercept. The scattered rays lead to a general blurring of the retinal images, by which the visual acuity is diminished. It is for this reason that tattooing of a nebula, with or without iridectomy, may lead to considerable improve- ment in vision. Corneal ulceration is always primary, that is, it only exists where there has been a focus of inflammation in the cornea itself, never where the focus lies somewhere else in the eye, and the corneal changes are of the nature of an interstitial infiltration. It is useful to remember this from a prognostic point of view. 'Some ulcers invade the more superficial layers of the cornea over its whole extent, without passing so deeply as to lead to perfora- tion. Others, again, more or less rapidly spread in depth, caus- ing perforation, without a great extent of the cornea becoming involved. Ulcers at the corneal margin usually increase in size, in very much the same proportion in both directions, spreading superficially in a circular line round the margin, and at the same time eating through the thickness of the membrane. From the point of view of treatment, there is more call for effort to be made to check the superficial extension than that which leads to an increasing breakdown of the deeper corneal layers. Both extensions have, of course, their natural limitations : the former ends when the whole of the cornea has suffered ulcera- tion ; the latter when perforation has taken place. As a general rule, however, healing is more apt to be delayed when the ulcer spreads comparatively superficially until all or most of the cornea has been destroyed ; whereas the destructive process often ends after perforation, in the essentially deep ulcers. This fact may sometimes be taken advantage of, especially in deep marginal ulcers, when, by opening into the anterior chamber, by punctur- ing the floor of the ulcer, farther extension may be avoided. Such treatment must not, however, be I'esorted to unless other attempts at arresting the ulcerative process have first been tried without success. It is better, if possible, that there should be no perforation. There is a danger of in this way permitting the entrance into the deeper parts of the eye of microbes, which may be a source of very serious complications. The danger is greater, too, when the perforation is done as a surgical measure than when it occurs in the ju'ocess of inflammatory destruction. Nevertheless, paracentesis is often useful, jmrticularly in the case of deep marginal ulcers, not only as tending to limit the extent of destruction to the cornea, but in preventing prolapse of iris, which is more likely to occur if the perforation takes 142 DISEASES OF THE CORNEA AND SCLERA. place siiontancously. Prolapse, too, when it does occur, is more easily dealt with if it follows a paracentesis, than if the hernia takes place through the base of an ulcer which has of itself yielded to the pressure from within. In the first case, it is recognised at the time, and can be replaced by a little careful manipulation, preferably with a thin pliable caoutchouc, or tortoise-shell iris-repositor, which should, of course, be aseptic. The iris can afterwards be kept away from the corneal wound by causing a forcible contraction of the pupil with eserine or pilo- carpine. The worst that can then happen is an attachment of a point on the surface of the periphery of the iris to the back of the cornea, without any subsequent actual incorporation of iris tissue in the cicatrix which eventually comes to occu})y the site of the ulcer. But even this may frequently be avoided. The following preparations of eserine and pilocarpine may be used for this purpose : — T^ Eserinne sulpliatis 2 grs. Acidi boracici . . . . . . 5 ,, Aqii.'B destillat;« . . . . . ^ oz. 1^ Pilocari)in?e nitratis ..... 2 grs. Acidi boracici . . . . . . 5 ,, Aqua; clestillat;ii . . . . . i oz. After a paracentesis, too, the eye should be bandaged for forty- eight hours. The bandage should, however, be removed and reapplied every eight hours, to admit of the eye being well bathed, and the drops of the miotic solution used. Where there is much secretion, the changing may be done more frequently. Prolapse occurring after spontaneous rupture is seldom dis- covered until some time after it has arisen — the incarcerated or protruding iris is then more or less covered with lymph. It is caught, too, in a more ragged and more structurally altered corneal perforation, and generally held sufficiently firmly to be with difficulty disentangled. Attempts at replacing the iris under these circumstances should not be made. They lead to laceration, and no doubt at the same time favour inoculation by the micro-organisms with which the incarcerated membrane is at least surrounded, and are very apt, therefore, to be followed by more or less serious iritis. As a general rule, it is better not to interfere at this stage at all. Even the use of miotics is probably best avoided. The ulcer may be carefully painted over with freshly prepared chlorine water to which a little hot water from the kettle has been added, so as to bring the tempera- ture up to blood heat or a little over, then dusted freely with PERFORATION. 143 very finely powdered (not sublimated) iodoform, and an occlusion bandage applied. The subsequent treatment suitable for iris prolapses will depend upon the size of the protrusion. Often in the course of the healing process a pretty marked protrusion is found to diminish greatly in size. When this takes place, and the hernia has become flattened down to nearly the level of the cornea, and well covered by cicatricial tissue, it is best left alone. More marked permanent protrusions should, however, be excised. They are a source of greater risk, from their liability to injury. Disturbance of their cicatricial covering may, under certain conditions, favour inoculation by mici'obes, and lead to iritis and deeper inflammations of the eye. The excision should not be undertaken until all irritation caused by the corneal ulceration has subsided — generally not, therefore, until a fortnight or more after the prolapse has arisen. The object aimed at in removing the prolapse is to flatten the protrusion down so as to bring it as nearly as possible to a level with the surface of the cornea. The proper way to do this is to transfix its base at about its centre with a small narrow cataract knife. The knife is then cut outwards in the direction at right angles to its edge, its surface being all the time kept parallel to and on a level with the cornea. When the one half has thus been separated, it is seized with a pair of fine-toothed forceps, raised so that the blades of a pair of scissors can be got to close below it, and at the same time over the remaining portion of the protrusion. A snip with the scissors, pressed somewhat downwards on to the cornea, can thus be made to sever the remaining half close to the corneal surface. Attempts at removing these prolapses with forceps and scissors alone do not lead to suflicient flattening, owing to slipping of the blades. After removal of an old prolapse, in the manner described, the eye may be tied up for four or five days. In addition to the flattening down of a prolapse, cases in which this accident has happened sometimes call for further treatment. It happens not unfrequently that the pupil is visibly drawn in the direction of the corneal cicatrix. It loses its cir- cular form, and becomes pear-shaped. Less pronounced degrees of this distortion and displacement of the pupil are of no con- sequence to vision, and are rarely the cause of any irritation. In the case of the larger hernias, however, the pupil may be rendered so eccentric that vision is thereby impaired ; and besides, the dragging on the iris fibres, which is the caitse of the displace- ment, may sometimes give rise to repeated attacks of congestion. 144 DISEASES OF THE CORNEA AND SCLERA. In such cases, two iridectomies should l)e done opposite to eacli other, at right angles to and on either side of the central point of the prolapse, or the synechia remaining after the prolapse has been levelled down. The iridectomies need not be large, and may both be done at the same time, though it is easier to allow some time — a week or more — to elapse before the second is done. Iridectomy is also called for where the scar of a perforating ulcer — whether there be, as is most frequently the case, iris tissue incorporated with it or not — is weak, and begins to yield to the intra-ocular tension. This condition, staphyloma, may indeed often be arrested by iridectomy, especially when it is partial. Moreover, it is only then that any effort to prevent further loss of vision by serious changes in the corneal curvature can be of any avail. Other operations for more pronounced degrees of corneal staphyloma are not particularly satisfactory. The treatment suitable for corneal inflammations, which do not present themselves as ulcerations, showing a marked tendency to perforation, must vary considerably according to their nature. The treatment of some forms has already been referred to in connection with conjunctivitis, but before discussing that which may be recommended in others, there are a few more general practical points to which attention may be directed. It is neces- sary to bear in mind, for instance, in connection with keratitis, that the origin of the local inflammation is j>erhaps most often to be found in that of some neighbouring part of the eye. One's attention should therefore always be directed to the state of the lid margin, conjunctiva, and tear sac. And this, even where the history points more or less clearly to some preceding trauma. In many cases, too, the state of the general health will have to be inquired into, and demand appropriate treatment. This is par- ticularly the case in struma, syphilis, diabetes, rheumatism, and gout, but also, though less commonly, Avhere other digestive or circulatory or nerve disturbances exist, or where functional or organic disorders of the reproductive system are present. In short, though local treatment may be indicated, it is comparatively seldom that nothing further is called for. Local treatment is least essential in the case of mere infiltra- tion, both superficial and deep, and most in the more virulent, rapidly spreading, ulcerations which have a septic origin. It used to be a common jiractice to content oneself with the occasional or frequent use of atropine dropped into the eye. This has no further effect on the local inflammation than to act to some ex- tent as an anodyne. Cocaine is much more useful in this respect, TREATMENT. 145 and therefore should be substituted for atropine where there is no complication with iritis. In all cases, however, the state of the iris should be looked to, and, where any marked congestion or any inflammation of that membrane exists, atropine should be used. In many cases, indeed, of bad ulcerative keratitis, a subacute iritis begins to show itself after the corneal condition has existed for some time. The iritis is no doubt caused by the action of toxins which pass through the cornea into the aqueous humour. All the different alkaloid solutions, used as " drops " for the eye, should be freshly prepared, and be made up with some anti- septic. They are otherwise apt to contain mycotic or other germs, and then likely to do more harm than good, by causing conjunctivitis, and thus indirectly tending to keep up or even aggravate many corneal inflammations. The pipettes or glass rods used for introducing the drops should also be rendered aseptic before use, and should never be brought into direct contact with the conjunctiva. In using cocaine, it must be remembered, too, that the anses- thesia which it produces is liable, by causing an arrest of the tear flow and of the other secretions by which the eye is normally lubricated, to give rise to a desiccation, or even, in extreme cases, a shedding of the corneal epithelium. It is therefore well to tie up the eye for some time after its application. On this account, it should not be too constantly applied. It is useful often, and especially where the corneal condition is associated with much photophobia, to precede the examination of an inflamed cornea by an instillation of cocaine. The cocaine drops, suitable for this and other purposes, may be prepared according to the following prescription : — J^ Cocainse hydrocliloratis .... 4-10 grs. Acidi boracici . . . . . 4 ,, Aqiiffi destillatse ..... 2 drnis. Eserine is now more frequently used in most corneal inflam- mations than atropine. I have never found it to have any eftect on the course of the inflammation, and consider that its use should be confined to cases where, fi'om possibility of peripheral prolapse of iris, it is advisable to obtain a powerful contraction of the pupil. In many corneal conditions one sees exemplified, in a way which in other parts of the body is not so readily followed, the struggle which takes place between the vitality of the tissues and the external forces, micro-organisms, toxins, and other irritai)ts 10 140 DISEASES OF THE COPvNEA AN J) SCLERA. which tend to (lestructioii. The liasis of one's treatment should tlierefore be, in the first place, either altogether to avoid measures calculated to diminish or inhibit the former, or make use of measures by which tlie vitality is temi)oi'arily increased without a swing subsequently taking place in the oj)posite direction. Again, our etibrts must be directed towards neutralising and kee{)ing in check the activity of the external irritants, in a manner, too, which does not impair vitality. Both heat and cold have important influences in these re- spects. The application of ice, which was formerly much in vogue, has been found practically to be worse than useless. Possibly, if the temperature of the cornea could be constantly kept at the freezing-i)oint of water, the use of ice might occa- sionally be of some value. The usual w^ay of applying cold by iced compresses does not maintain the desired low temperature, and no doubt the explanation of the harm done by this treatment is the disproportion which it establishes between tissue vitality and activity of external irritants. By the ordinary applications, the lowering of the former is not compensated for by the degree of inhibition caused in the latter. This disproportion is indeed much less in the case of the different antiseptic ^^reparations, which may be used both more efficiently and more conveniently. But inasmuch as these no doubt to some extent lower the vitality of the cornea, it is often advantageous to combine with their use that of heat directly applied. Practically, it is found, however-, that although heat is more efficacious than cold, its application can be overdone. It is certainly not suitable in all cases. The effect of heat must be got as far as possible without that of poulticing. The simplest way to do this is as hot fomentations, lasting a quarter of an hour or so, every two or three hours. Dry heat may also be used, but is more troublesome to apply, and has no particular advantages. Poulticing in any form is always more or less hurtful. The advisability of tying up the eye or not is a question which often presents some difficulty. In itself, it would seem to afford a natural means of keeping the eye at rest. In point of fact, it is, with certain exceptions, a useful treatment when properly done. But it must be remembered that there is some danger, and, in certain forms of corneal inflammation, great danger, of the tying up causing a poulticing action and a retention of the secretions, both of which may entail much more risk than is run by leaving the eye uncovered. Bandaging should therefore not be continuous, but the bandage should be removed two or three times or oftener during the day, and need not be applied at all at night. At each TREATMENT. 147 removal the eye should be properly bathed with boracic lotion or hot Avater, which has sufficiently cooled after boiling, and any other local application made which may be considered necessary. (Jn account of the frequent necessity for removing the bandage, it should be in a form which can readily be replaced by the patient himself. A good form of occlusion bandage for this purpose is a piece of flannel 6 in. long and 2 1 in. wide, to each corner of which a piece of tape is sewed. The two tapes at each end con- verge into one. The bandage is applied over a j^ad of Gamgee tissue or absorbent cotton-wool. It is carried diagonally over the eye — the two long tapes being crossed at the back of the head and tied over the forehead. It should be tied comfortably tight. Knitted bandages similar in shape are also good. The different local applications which may be used in cases of corneal inflammation (in addition to yellow oxide of mercury, which it must be remembered is only suitable in strumous or eczematous superficial keratitis) are — iodoform, chlorine water, and boracic lotion, tincture of iodine, nitrate of silver, pure carbolic acid, and the actual cautery. Iodoform is an extremely useful application, which may be used either finely powdered (not sublimated), or as an ointment in the proportion of 1 in 8. Gelatin discs, containing iodoform, have also been used. They, however, melt rapidly, and leave very little iodoform. On this account, it is much more satis- factory to dust the pure iodoform on to the cornea. This may be done freely. The ointment, too, is not so good, but is more readily applied by the patient himself, and is, moreover, more suitable when the eye is not afterwards bandaged. Chlorine water need only be used in severe ulcerations which are rapidly spreading, either superficially or in depth. It may be used both in the form of a wash or injected subconjunctivally. The subconjunctival injection should be made with a hypodermic syringe, introduced at two or three different points. Five or six drops may be injected at each point. The chlorine water is more diffusible, and does not cause any more pain at the time, or any more reaction afterwards, than solutions of corrosive sublimate, which are more generally used. Chlorine water must be freshly prepared. If it has stood for some time it causes much more irritation, and is besides less efficacious. As a sub- conjunctival injection, it should be used fully saturated. In the same full strength, it may be freely dabbed on to the surface of a corneal ulcer w-ith a camel's-hair brush. As a wash, it is better to use the fresh saturated solution, mixed with about twice its volume of warm water. 14S DISEASES OF THE CORNEA AND SCLERA. Roracic lotion is suitable for all cases, even where the inflam- mation is confined to localised infiltrations. It is the most convenient way of keeping the eye clean by removing the con- junctival secretions. It may be used saturated and mixed with some hot water, so as to bring its temperature up to that of the body. The best jjlan is to trickle it into the eye, squeezed out of a i)ledget of absorbent cotton-wool, Avhich is thrown away after it lias been used. The patient may do this fairly well himself, by throwing back his head, and holding down the lower lid with the one hand. Tincture of iodine is only called for in the severer cases of ulceration. It is aiJjjlied directly to the ulcer with a camel's- hair brush. It is a fairly good substitute for the actual cautery, when that is not at hand. In some cases its application may be preceded by scraping the ulcer, which can be done painlessly under cocaine. In less severe, more superficial, and especially vascularised ulcers, which are not of strumous origin, the iodine may be used as an ointment. A convenient form is as a 1 per cent, solution of pure iodine, in purified white vaseline. This should be rubbed on to the everted conjunctival surfaces with the point of the finger, and the lids then allowed to close over it. It produces only slight irritation as a general rule. For strumous superficial vascularised ulcers, the yellow oxide of mercury has already been referred to as the most efficacious application. Nitrate of silver in solution is a very useful agent in all cases of superficial non-vascularised ulcerations. It is particularly to be recommended in ulcers of this kind, in which the base of the ulcer is more or less markedly infiltrated, but which the absence of pus in the anterior chamber (hypopyon), and more especially of any deep purulent infiltration of the margins, .show to be not of the most dangeroiis septic order. Catarrhal ulcers in old people, to which reference has already been made, are especially benefited by one or two applications directly to their surface of a 2 per cent, solution. It is well to remember that it is inadvis- able to repeat the application too frequently. The practical guide is afforded mainly by the extent to which the use of the caustic solution" has relieved the pain. If, the next day after its application, the pain is found to be much less, it should not be used again. A careful examination of the ulcer will then reveal indications of healing. The rough, ragged margins will have become more or less rounded, owing to epithelial growth. One's object is merely to induce healing, and further applications only destroy the newly formed epithelium, and thus interfere with the natural process of reparation. TREATMENT. 149 Pure carbolic acid, applied directly on a Avooden match, is a useful disinfectant for the severer forms of septic ulcer when a suitable actual cautery is not at hand. The actual cautery is un- doubtedly the best means we possess of checking the spread of a serpi- ginous septic hy[)opyon ulcer of the cornea. Cases of this kind are very frequent, and are the principal cause of unilateral blindness. They almost invariably oi'iginate in some more or less trifling injury to the cornea, by which some portion of its epithelium is denuded, and its deeper layers inocul- ated with septic matter, which may be introduced either by the body with which the injury is caused, or by micro- organisms which exist at the time in }« the conjunctival and tear sacs. The <» importance of this latter connection has j already been considered. In the treat- £ ment of these severe destructive corneal inflammations, much depends often upon the efficiency with which the actual cautery is applied. In some cases, how- ever, the virulence of the process is so great that it may be impossible to check it. In such cases, the specific microbe at work is generally either the pneu- mococcus or the gonococcus. The two best means of applying the actual cautery are by means of the galvano- and the thermo-cautery. Provided the thermo- cautery point used is a fine one, so that its action can be jn-operly limited, it is in every way equal to the other. The cautery should be made to burn suffici- ently through all the deei)ly infiltrated margins of the ulcer. It is by these abscess margins that the ulcer spreads, and they must be properly destroyed. The other portions of the ulcer, and there are usually some such, which do ^- ,Sd' J't;r;:;:nl'^S not present infiltration at the margin, infected corneal ulcers. 150 DISEASES OF THE CORNEA AND SCLERA. may be left. By using cocaine, the little operation may be done without causing pain. The indication that the process has been arrested by this proceeding is afforded by the diminution subsequently of pain, by the diminution in the amount of the hypo- pyon, and the more satisfactory appearance of the ulcer margins. These septic ulcers are often very painful, and may for nights interfere with sleep. After efficient cauterisation, the l)atient is able to sleep, the hypoi)yon dimin- ishes in amount, and the edges of the ulcer appear clearer, or merely, it may be, slightly charred. The subsequent treatment should consist in the use of chlorine water as a lotion, and iodoform in the manner just described. It is sometimes necessary to repeat the cauter- isation. This should be done on any return of pain, if, at the same time, a little yellow point of infiltration shows itself at any })oint of the ulcer margin. Should a really efficient application of these measures, repeated, it may be, once or twice, fail to ari'est the process of destruction, the best plan to adopt is to 0})en freely into the anterior chamber through the base of the ulcer. This treatment, by what is called Saemisch's section, at one time constituted one of the great ad- vances in ocular surgery. Now that the actual cautery is used, it is comparatively seldom called for. A narrow Graefe cataract knife is entered at one side of the ulcer, passed across the anterior chamber, and brought out again at a point beyond the opposite margin, and then made to sever the Avhole base. In doing this operation, the part selected should, as far as possible, be made to include the margins which are most infiltrated. The moment the section is made, and the hypopyon escapes, there is a sudden hyi»eraemia of the iris, the vessels of which may even give way, and great, often agonising, pain experienced. This pain passes off in a few minutes, but it is as well to know that it is sure to occur. Something has already been said, though mainly with refer- ence to prognosis, of the opacities which remain in the cornea Fui. 52. — Galvano- cautery. TREATMENT. 151 after the subsidence of an inflammation. The area of intrans- parency may be due, as we have seen, to either infiltration or cicatrisation, or both. The question as to what, if anything, can be done to hasten or promote the clearing away of these intransparencies will often present itself. Cicatricial opacities, in adults at all events, remain indefinitely practically the same, and no treatment is known by which they can be removed. Different stimulating and irritating applications have been tried. Repeated puncturing with fine needles and electrolysis have also been resorted to, with, however, absolutely no effect. Attempts have been made, too, at different times and in different ways, to transplant portions of clear cornea from other eyes, human and Fig. 53. — Case of partial stapliyloina of the cornea for which iridectomy has been done. animal, after removing bits of corresponding size from the opacities. The transplanted corneal tissue has generally retained its vitality, but has so far invariably failed to retain its trans- parency, and thus the final effect of the operation has been nil. It is otherwise with opacities which are the result of infiltra- tion alone. The general tendency with these is to clear away more or less completely, and with varying degrees of rai)idity. Their absorption is often slow, and indeed seems, in some cases, to come to a standstill altogether. In such cases there are various means at one's disposal which are to some extent of use in promoting and stimulating the desired absorption ; of these, the ones chiefiy to be recommended are : massage of the cornea, 152 DISEASES OF THE CORNEA ANJ) SCLERA. iodine, turi)entine, and sulphate of copiier. In very severe cases of dense pannus, the irritation necessary to promote absorjjtion may even be got by inducing a purulent conjunctivitis. Massage of the cornea is best done through the lid. The lid is rubbed quickly over the cornea, and with gradually increasing force, for half a minute, or more, at a time, once or twice daily. To do this effectually, the rubbing must give i-ise to a moderate degree of surrounding hypcramiia. The massage may also be combined with the use of the iodine ointment already referred to. A good and not too strong stimulating effect may be got by the daily use of the following prescription : — R Olei terebinth. . . . . . 1 drni. Olei amygd 2 ,, Sifj. Eye-drop.s. Misce. Sulphate of copper is most useful in trachomatous pannus. It should be used in the shape of crystals, from which the sharp edges and points have been ground down. The inner surfaces of the lids are lightly touched with these crystals, and some of the salt is then dissolved in the tears, and is thus brought in contact with the cornea. The very serious consequences to the cornea which are likely to accompany purulent conjunctivitis must necessarily greatly limit the application of the last measure, which has been referred to as a means of stimulating absorption in the case of dense infiltration opacities. The vascularised cornea is, however, better able to withstand the destructive influence of the gonococcus. In dense vascularised pannus, which has given rise to so much intransparency as to practically destroy vision altogether, it is sometimes justifiable, in view of the possible brilliant results which may thus be obtained, to inoculate the eye with some of the discharge from a case of true gonorrhceal conjunctivitis. This is, however, only justifiable if both eyes are affected. The risk should not be run as long as one eye has retained sufficient vision to enable the patient to find his way about, on accoiint of the possibility of its being also attacked by the specific inflammation. Such an accident might happen as the result of any inefficient application of the means which have been referred to by which the sound eye may be protected. In any case, before adopting a cure of such severity, the patient must, of course, be made fully aware of the suffering he will have during the first stage of the inflammation, and of the risk of complete destruction of the ej^e with which it is associated. The inflammation, too, must be kejjt in check as far as pos- TREATMENT. 153 sible by the antisei)tic measures which have already been described. Another less severe method, but at the same time one which is far less effectual, though entailing no risk of the loss of the eye, is to perform the operation of peritomy. This consists of removing a ring-shaped portion of conjunctiva immediately surrounding the cornea. To do this the conjunctiva is circum- cised with a pair of scissors, at a distance all round of about I in. from the cornea. It then retracts, leaving a gaping wound, which is further enlarged by cutting away bit by bit the annular portion which surrounds the cornea. Each bit is seized with a pair of fixation forceps, and cut off close up to the cornea with scissors. The wound is then allowed to cicatrise without any stitching, and under the ordinary antiseptic pre- cautions. The cicatrisation, which slowly takes place, has the effect of causing the greater or less disajipearance of the super- ficial new-formed vessels in the cornea, and, with them, of some of the infiltration. Many forms of primary keratitis are of comparatively rare occurrence. Their proper local treatment will usually be on the lines already discussed from a more general point of view. In the case of superficial ulcers which show a marked tendency to recurrence at frequent intervals — once a month or oftener — the cause of recurrence may often be found to be evidently due to insufficient tenacity or vitality of the epithelium which in the process of recovery is formed over the site of the ulcer. There is thus a tendency for this epithelium to be shed or separated from the underlying tissues in the form of a bleb, often of considerable size. No doubt this occurs owing to some slight injury, such as forcible rubbing of the lid over the eye. Such an injury, however, often occurs during the night, so that the patient is unable to give any other history of the cause than that of suddenly awakening with the feeling of intense pain in the eye. Such a history should always lead one to make a careful examination of the cornea, and it will usually be found that, by sliding the lower lid over it, some portion of its epi- thelium wrinkles up and reveals the presence of a collapsed bulla. The treatment which should then be adopted is to drop some cocaine into the eye, strip off" the detached epithelium with a pair of iris forceps, wash with warm boracic acid solution, and apply a bandage. With regard to the treatment, other than local, of corneal inflammations, it is difficult to give any i)recise directions. As a general rule, medical treatment in such cases is of com- 154 DISEASES OF THE CORNEA AND SCLERA. paratively little importance. Yet it is always advisable to take the general health into consideration. Often one has to deal with essentially strumous individuals, in whom the diathesis has a more or less direct connection with the local inflammation. The same is true, though to a less extent, in gout, rheumatism, dyspepsia, and an;ijmia. Possibly, also, uterine and other female disorders may sometimes have an influence ; they certainly have in connection with some deeper afl"ections of the eye. Much may be done by dieting, Turkish baths, massage, and change of air. The drugs which may be used with more or less reason are iron, arsenic, quinine, salicin, and iodide of potassium. In certain recurring types of corneal inflammation, baths appear to do good. I have repeatedly sent jiatients to Strath- peffer, Buxton, Harrogate, Droitwich, and Bath in this country. Others, again, have derived benefit from one or more visits to Aix-les-Bains, Contrexeville, and Brides-les-Bains, in France ; and Wiesbaden, Ems, Nauheim, Schwalbach, Schlangabad, Carlsbad, and Kissingen, in Germany. I have also found some of the higher health resorts in the Engadine and in Norway of great use in the treatment of strumous and tuberculous forms of corneal inflammation. Special Forms of Primary Keratitis. Phlyctenular keratitis. — This very common afiection is not properly characterised by the name which it most frequently gets. But as it is the process in the cornea which corresponds to phlyctenular conjunctivitis, with which it is very frequently associated, there seems no reason to prefer such names as scrofulous or lymphatic keratitis, or herpes, or eczema of the cornea, which have been by some substituted for it. Phlyctenular keratitis occurs in the form of single or mul- tiple, small, superficial, and, at first, usually non-vascularised, infiltrations of the cornea. The size of these infiltrations is rarely more than a jjin's-head. They are of a greyish colour, and slightly prominent. Frequently they break down into small ulcers, which do not as a rule exhibit any tendency to spread either superficially or in depth, but which frequently become vascularised. A slight nebulous spot remains for some time after healing has taken place, but eventually disapi)ears entirely. Sometimes the little infiltrations are decidedly yellow or purulent, and break down into ulcers, which lead to destruction of some of the true corneal tissue, and therefore to more })ermanent nebulae. A certain, and often considei'able, amount of jjinkish PHLYCTENULAR KERATITLS. 155 circumcorneal injection is met with in this affection, and there is at the same time ahnost invariably a good deal of lachry- mation and photophobia. The photophobia is often so intense in children as to lead to most persistent blepharospasm. The most common cause of phlyctenular keratitis is struma, but it is often met with where there exists some constitutional depression not necessarily of a strumous nature, such as weakness after exhausting illnesses, measles, scarlet fever, etc. In strumous chikken it is very apt to recur once a year or oftener for some time. Altogether the affection is much more common in children than in adults, and usually, when met with in adults, there is a history of previous attacks in childhood. Except in more markedly purulent cases, the treatment, in children at least, should consist mainly in the local application once daily of the yellow oxide of mercury ointment (Pagen- stecher's) of the strength of 8 grs. of the yellow oxide to 1 oz. of unguentum cetaceum, to which a few drops of almond oil may be added to keep it from becoming hard. Spermaceti is better than vaseline, which sometimes irritates. This ointment is certainly better than any other form of mercurial preparation. Whether this is owing to its stimulant or its antiseptic pro- perties, or to some other cause, is not very evident. Adults do not tolerate it so well as children. They require altogether less stimulating local treatment ; atropine, cocaine, and weak anti- septic applications, such as a 2 per cent, boracic lotion, or a lotion of corrosive sublimate, 1 in 5000 or 10,000. The internal administration of cod-liver oil is of great service in children. Attention should also be given to keeping the skin clean. For adults, quinine, or, in the strumous, the syrup of the iodide of iron, are indicated. Tying up the eye is not only unnecessary, but does harm, partly on account of encouraging the photo- phobia, and partly owing to the poulticing action which is apt to be caused by the bandage or cloth when saturated with the tears which are usually copious in this affection. At most a shade may be allowed on account of the photophobia, but it is better as a rule to try in every way to combat this condition. The photophobia is sometimes so severe, and at the same time so out of keeping apparently with the actual severity of the inflammation, that it must be looked upon more as an induced neurosis which calls for sjtecial treatment. (See p. 118.) Fascicular keratitis. — Closely allied to phlyctenular kera- titis etiologically, and indeed often occurring along with it, but constituting a distinct clinical type of corneal inflammation, is what is called fascicular keratitis. This is a vascularised infll- 15G DISEASES OF THE CORNEA AND SCLERA. tration, the vessels in wliicli run }tarallel to each otlier, so as to form a dense band or fasciculus about a line in breadth stretch- ing into the cornea (Fig. 54). At the end of the vascular leash the infiltration is somewhat more or less crescentic in shape, and often ulcerated. Occasionally two or more of such infiltrations are to be seen stretching in towards the centre of the cornea, and although most commonly the course taken is a straight one throughout, there is sometimes a more or less decided bend made. When devascularised, a nebulous streak is left, which very slowly clears away, and is always most dense and persistent at the end farthest into the cornea. This portion ^ ^r^ y nr ^ T^ ' Fig. 54. — Fascicular keratitis. often remains indeed a permanent opacity. The accompanying sym})toms — circumcorneal injection, i>hotophobia, and lachryma- tion — are the same, and exhibit much the same differences in intensity, as in the case of })hlyctenular keratitis. The affection is mostly strumous, and almost entirely confined to children. The treatment is the same as for phlyctenular keratitis, only in these cases Pagenstecher's ointment is even more valuable, and .seldom fails to arrest the progress of the inflammation in a few days. It causes first of all a gradual disappearance of the band of vessels, and subsequently pi'omotes absorption of the infiltrat- ing cells. It is important to check the progress before the centre of the cornea is reached, as the opacity left is of course PANNUS. 157 of much more serious consequence if situated directly in front of the pupil. Where, at the time the case comes under observa- tion, the portion of the infiltration at the end of the fasciculus of vessels should happen to occupy just the centre of the cornea, it is better to allow it to be pushed, as it were, a little farther before trying to check it, so as to allow the pupillary area to be occupied by a vascularised portion, which is more completely absorbed, and therefore does not eventually interfere so much with vision. Pannus. — This consists for the most part of a development Fig. 55. — Showing the condition of pannus in the upper portion of the cornea, also cicatrices in the conjunctiva of the upper lid in a case of trachoma. of new vessels in the superficial layers of the cornea. The vessels spring from those of the conjunctiva, and course im- mediately below as well as above Bowman's membrane. At the same time there is more or less irregularity of the corneal epithelium over the vascularised portion, and some diffuse infil- tration into the tissues occupied by the newly-formed vessels. There are great differences both in the extent and intensity of the vascularised area. When very dense the cornea assumes quite a raw fleshy appearance, a condition known, therefore, as pannus a'assus. 158 DISEASES OF THE COI^NEA AND SCLERA. Paniius occurs iirincii)ally in connection with trachoma (see Fig. 55) and long-continued .strumoas intiltrations of the cornea. We may therefore distinguish a trachoDiatous XK^nnun and a fttrumouK jKumiis. Trachomatous panuus is apparently due to an extension of the granular inflammation from the conjunctiva to the cornea. In many cases, where the granulations are massive, there is found to be no pannus ; while in others, again, a marked degree of pannus is associated with comparatively slight alterations in the palpebral conjunctiva. This dispro- portion between the condition of the conjunctiva and cornea in different cases shows that the latter is not the result of friction, though this connection has been assumed from the fact that the ^'-;np',^^r^ Fig. 56. — StrumoTis pannus, showing large development of superficial vessels in upper part of cornea. pannus often occupies only the upper portion of the cornea, extending over an area corresponding to that covered by the upper lid. One frequently sees a pannus all at once .set up, along with an acute exacerbation in the conjunctiva, in cases which have long remained free from corneal complication. In spring catarrh, too, in which the I'oughness of the conjunctival surface may attain a degree rai'ely if ever .seen in trachoma, there is never any pannus. Strumous panuus is more frequent in young adults than in children. It is always a very chronic affection. Sometimes the infiltrations extend in depth, and become purulent, leading eventually to actual perforation of the cornea. The opacity produced by pannus may, in course of time, disappear under treatment, the vessels becoming first HYPOPYON KERATITIS. 159 attenuated and less numerous. Long - continued cases often result in a hopeless opacity from a kind of cicatricial organisa- tion of the infiltrated cells. Some, again, lead to alteration in the shajje of the cornea, deepening of the anterior chamber, and eventually also to changes in the iris, with secondary glaucoma. An indication of the presence of such deeper complications is often afforded by a marked intolerance to the usual local appli- cations. In other cases, perforation, followed usually by more or less shrinking of the eye, may take place. The treatment of trachomatous pannus mainly consists in treating the conjunctival affection. The strumous form is best treated, unless it has gone on to ulceration, with Pagenstecher's ointment and massage, in the shape of friction through the lid, Fig. 57. — Case of small infected corneal ulcer with hypopyon. along with suitable general treatment. Very long-continued dense cases of pannus may sometimes (see p. 152) be caused to clear up by inducing a purulent inflammation of the con- junctiva. Many cases are much benefited by the operation of canthoplasty for the enlargement of the lid aperture. Hypopyon keratitis, — A good many deep-seated abscesses of the cornea are associated with hypopyon, an accumulation of pus in the anterior chamber. Not infrequently this complica- tion is met with in the more severe cases of strumous corneal inflammation, which occur mostly in children. Great difterencea exist in the density of the hypopyon ; Avhen very thick and fibrinous, it may not fall down to the bottom of the chamber, but remain sticking to the po.sterior surface of the cornea. IGO DISEASES OF THE CORNEA AND SCLERA. A very distinct cliniciil funn of intiaiiiination of tlie cornea is what is usually in this country sjjocially understood Ijy the term hypopyon keratitis, owing to its always being comi)licated with the appearance of pus in the anterior chamber. This affection occurs as an ulcer, some part of the irregular margin of which is densely infiltrated w^ith pus. The characteristic feature of the ulcer is that it extends in the direction of this infiltrated margin, for which reason it has received the name, more expressive of its serpiginous nature, of ulcus cornecB serpens (Fig. 58). Fig. 58. — Case showing irregularly shaped spreading margin of infected corneal ulcer with hypopyon (hypopyon keratitis). The origin of this form of keratitis is in almost all cases a trauma, which has been followed by an inoculation with pus from a previously existing daci-yocystitis or chronic conjunc- tivitis. Those whose occupations cause their eyes to be sub- jected to continual irritation, as well as occasional injuries, are most liable to contract this inflammation. The inflammation is of a septic nature, and caused by the presence of microbes which exist in the discharges from chronically inflamed mucous sur- faces. As the ulcer extends, more and more pus finds its way into the anterior chamber. Although absorption of the pus no DENDRITIC KEPwYTITIS. IGl doubt constantly goes on, yet, as long as there is any active inflammation in the cornea, it is more rapidly secreted than absorbed. Increase in the amount of the hypopyon is therefore a certain evidence of progress in the process of destruction in the cornea. As long too as the yellow margin of infiltration exists in the cornea, extension is taking place. The natural course of the inflammation is for the ulceration to go on spreading, until the whole of the cornea in the direction of the creeping infiltra- tion has become involved ; and as this often takes place in two or more directions, seldom in all at the same time, it is not an uncommon thing for the whole cornea to be ulcerated. The complications of hypopyon keratitis are those already described as met with in connection with severe ulceration, though, owing to the greater tendency to superficial as compared with deep spreading, the more serious complications are not very frequent. The treatment should be directed to first destroying the area of infiltration and then applying antiseptics. The way in which this may be done has already been referred to (see p. 149). If the ulcer has been central, as is often the case, it is neces- sary subsequently to perform iridectomy, so as to displace the pujiil to opposite a clear portion of the cornea. In most cases it is advisable at the same time to treat the tear sac in the manner already described. Owing to the tendency to iritis, it is well to keep the pupil dilated until the healing process has advanced to such a stage that there is no further danger of such a com- plication. Dendriform (mycotic) keratitis. — The characteristic of this inflammation is a great tendency to a kind of ramifying super- ficial extension (see Fig. 59). It is a very chronic aff"ection, and the amount of infiltration surrounding the ulcerated rills which it forms is so slight as to render the peculiarity of its propaga- tion liable to escape detection, unless a proper examination be made by oblique illumination. The pain caused by this in- flammation is, as a rule, slight, though sufiicient to give rise to some discomfort and photophobia. When uncomplicated, dendriform keratitis is always super- ficial and not accompanied by hyi)0}>yon. In not a few cases, however, which begin in this way, and no doubt as the result of inoculation with more active micro-organisms, a serpiginous hypopyon ulcer may make its appearance. The cause is not known, though it is evidently a mycotic one. It is best treated by dabbing on to its surface some absolute alcohol with a camel's- hair brush. Usually after the first application the symptoms II 1G2 DISEASES OF THE CORNEA AND SCLERA. subside, and the treatment need only be repeated whenever they again become aggravated. This variety of keratitis leaves a characteristic scar, which tends to clear away slowly in the course of time, tliough it rarely disappears entirely. Clear corneal ulcers. — A clear form of ulceration of the cornea — that is to say, one in which neither the base nor the margins of the ulcer exhibit any infiltration — occurs almost exclusively in old enfeebled individuals, and is accompanied by little or no circumcorneal injection, and often by few, if any, subjective sym})toms at all, beyond more or less interference with vision according to its site. The infiltration statue of this »1X^^ Fig. 59. — Case showing an extensive superficial ulceration of the dendritic tj'pe. type of ulcer is rapid, and therefore rarely observed ; the healing stage is, on the other hand, very chronic. It is this circum- stance which gives rise to the name clea7' tdcer. The treatment most likely to stimulate these ulcers to heal is the use of hot fomentations. Marginal ring-shaped ulcer. — A long, narrow, ulcerated rill sometimes forms on the margin of the cornea, and extends in a ring-shaped manner round it. When occurring in children it is always caused by the confluence of a number of separate foci of inriammatioia. Such an origin, though probable, cannot always be demonstrated in the case of the less distinctly ULCUS RODENS. 163 strumous form which is met with in adults. The infiltration is seldom great, but this form of ulceration is accompanied by a good deal of circumcorueal injection and other symptoms of irritation. By extending completely round, the clear central portion of the cornea may be deprived of its source of nourish- ment to such an extent as to necrose. In severe cases, which are fortunately rare, complete loss of the cornea may be caused by this form of ulceration. The etiology is not always clear, but it often comes on in connection with some form of catarrhal conjunctivitis. The treatment should be directed towards preventing the spread of the ulcer. This is best done by paracentesis, which may be frequently repeated if necessary. Eserine and corrosive sublimate lotions are also useful. Occa- sionally it may be found advisable to use the actual cautery, followed by iodoform ointment. Mooren's rodent ulcer. — This disease, though previously known, was first recognised as a definite tyjje by Mooren. It is a rare affection, which, though in some respects like the ulc^is cornece serpens, is distinguished by being essentially chronic, lasting before complete cicatrisation for three or four months at least — not unfrequently for a year or more. It generally begins as a small superficial ulceration at some part of the cornea close to the corneo-scleral margin. In appearance it is so like catarrhal or eczematous ulcers that it cannot be distinguished from these. Yet there is in this form some inherent tendency to slow invasion of the cornea, both superficially and in depth, which presents much the clinical aspect of an epitheliomatous degeneration. The ulcer itself, owing to its slow progression no doubt, has mostly a clear base, except in parts which have undergone a sort of healing, and which are covered by imperfect epithelium and a few newly formed blood vessels. The margin separating the ulcer from the unimpaired cornea, and which represents the irregular line which superficial extension is taking, is occupied by a whitish overhanging area of debris, and is therefore opaque. Progression is not as a rule continuous. Periods of i:)artial healing or cessation of the jn-ocess intermit with others in which the advance is more rapid and active. When untreated, or when the treatment adopted has failed to arrest the disease, the whole surface of the cornea, to a depth of a quarter or more of its thickness, becomes converted into cicatricial tissue, the density of which may diminish slowly in the course of time. Vision is thus greatly reduced, though apparently not often to the extent of causing practical blindness. Usually sufficient vision remains to enable the patient to guide himself. No cause is known for 1G4 DISEASES OF THE CORNEA AND SCLERA. this disease. It appears not to l)e due to tlie i»resencc of any microbe. The only treatment is the actual cautery. The chance of arresting the ulceration depends greatly ujjon the completeness with which the cautery is used. As in the case of the septic form of serpiginous ulcer, particular care nuist be taken to thoroughly burn through the tissues of the spreading margin. Mooren's ulcer is usually met with after the age of 40, though it may occur in younger intlividuals. In elderly })eo])le, whenever a superficial marginal corneal ulcer makes it ai)i)earance, un- associated with an evident conjunctivitis, it is advisable not to delay the use of the cautery long should it show any tendency not to heal. No harm can be done by cauterising at this stage, and the develo})ment of the rodent character may thus not unlikely be checked. It seems possible that this type of disease may in some individuals be the result of an irritation directly ascribal)le to the treatment adopted. Thus I have seen two cases which were greatly aggra\'ated by the use of Pagenstecher's ointment. Vesicular keratitis. — A number of varieties, more or less distinct in their clinical aspects, occur in which the surface of the cornea is raised up into vesicles, which may be small or large, and single or multii)le. One of the most interesting and distinct forms is that to which Hansen Grut has drawn attention — a recuiTent bullous keratitis^. This form only comes on after a superficial wound of considerable extent, and presents itself as a clear bulla, which cannot properly be seen except by oblique illumination, and which may occuiiy from one-eighth to one-half of the sujierficial extent of the cornea. The numl^er of times that this condition may recur after a trauma, as well as the length of the interval between each attack, is subject to consideral)lc ditt'erence. It is not uncommon to find a recurrence take place from three to six times a year for several years. The attacks invariably come on in the morning on waking, with circumcorneal injection, considerable, often intense, pain, and the sensation as if there were a foreign body in the eye. Under these circumstances, and with a previous history of an external abrasion of the cornea, followed by the same kind of pain, there is always to be found a corneal bulla. Sometimes, indeed, this cannot be seen without pressing the lid against the cornea, the epithelium of which is then thrown into a fold, or by catching hold of the anterior epithelial surface of the separated layer with an iris forceps, when it readily comes away. Only very rarely is the BULLOUS KEPiATITIS. 165 liquid contained in the bulla other than completely transparent. When yellowish or purulent some opacity is left, otherwise complete restitution takes place, so that the cornea becomes to all apijearance absolutely healthy. A large superficial abrasion is very frequently followed by this form of inflammation, and, on the other hand, its occurrence at once leads one to the diagnosis, before the history of the original injury has been elicited. This, too, on account of the severity of the injury, there is very rarely any difficulty in obtaining. A cure takes place generally in from three to five days, except in the cases where the bulla is discoloured. One of the most common causes of this afiection is a scrape from a child's nail, and probably on this account, more than on any other, it is more frequently met with in women than in men. Other injuries, such as blows from branches or the end of an umbrella, may set up the same train of symptoms. The cause of the tendency to recurrence appears to be imperfect healing. The epithelium which replaces that removed at the time of the accident is more liable to injury, so that after a time the slightest rub, which may take place during sleep, will cause it to be detached in the shape of a bulla. The treatment consists in removing the detached epithelium with a pair of iris forceps, and applying cocaine frequently to allay the pain, using at the same time some sim[)le weak antiseptic lotion for bathing the eyes. The eye should then be tied up. There appears to be no way in which the recurrence can be prevented. Another bullous form of keratitis, in which the bulla is not pellucid, occurs in cases of chronic inflammation of the eye, where there is or has been increase of intra-ocular tension. It is most frequently met with in old cases of glaucoma or irido- choroiditis, where the disease has led to complete, or almost complete, blindness. The bulla in these cases is due to an oedema of the cornea, which has led to the formation of a fibrinous false membrane between the epithelial cells and Bowman's membrane : it is this membrane, in addition to the ei^ithelial cells, which forms the anterior wall of the vesicle. No treatment is called for in such cases, which are more of the nature of degenerative changes than of inflammation. Secondary keratitis. — One form of secondary infiltration of the cornea is of very common occurrence, what is usually known as interstitial keratitis. This never leads to any ulceration of the cornea. It produces a very characteristic ai)i»earance, beginning as a diffuse greyish and tolerably deep-seated opacity. 166 DISEASES OF THK t CORNEA AND SCLERA. which generally stretches in from some portion of the periphery of the cornea. The whole cornea may become pretty uniformly ^^^1'♦'!lv/Yn^^'^' Fig. 60. — From a ca.se of uoii-vascularisL-d. interstitial kfvatitis — later stage at which the inliltration is uoufiiied to central portion of cornea. infiltrated, while at the same time there is a very definite stijipling of its epithelial surface. Not infrequently different Fi(!. 61. — From a case of diffuse interstitial keratitis with dense vascnlarisation at upper margin of cornea. portions of the Cornea are more densely infiltrated than others, or there may even be a very distinct punctiform arrangement of INTERSTITIAL KERATITIS. 167 the infiltration, but there is never any prominence at such points as is seen in cases of primary infiltration. According to the density of the infiltration, the colour which it assumes is either white, grey, or yellow. When very dense it would be impossible, indeed, from the colour alone to say that no abscess was present. The degree of irritation is very variable, both in different cases as well as at difterent stages in the same case. There is usually circumcorneal injection, with photophobia and lachrymation, and often a more or less dense formation of new vessels in the cornea, giving rise to an appearance which has been called the "salmon-coloured patch." These vessels spring Fig. 62. — Vascularist-il interstitial keratitis. from the deep episcleral network which exists around the cornea, and therefore from branches of the anterior ciliary arteries. They can thus readily be distinguished from the newly formed vessels of a pannus, which spring from superficial conjunctival trunks. As the intransparency clears away, the new vessels, as well as the other symptoms of inflammation, gradually disappear. As a rule, the central portions of the cornea are the last to clear up. Both eyes are usually attacked by this inflammation, though rarely exactly at the same time ; more commonly the disease is pretty far advanced in one eye before the .symptoms make their appearance in the other. Interstitial keratitis always lasts a long time — three to ten 1G8 DISEASES OF THE CORNEA AND SCLERA. montli.s as a rule. In some cases the duration is much longer. There is a great tendency for the iris to hecome inHanied at the same time, and there are also ()])servahle in most cases changes in intra-ocular tension — at first generally an increase, but after- wanls, and continuing longer, a diminution, which is sometimes very marked. These circumstances, taken in connection with the absence of ulceration which characterises interstitial keratitis, sufficiently show that the disease is in reality not a true in- flammation of the cornea itself, but merely au extension to it of inflammatory products derived from a focus of inflammation in the anterior portion of the uveal tract. The age at which the disease most fretjuently shows itself is from 7 to 21. Individuals who are of delicate constitution from any cause are subject to it. The most frequent j)re- disposing cause appears to be inherited syphilis, as it is often met with in individuals in whom there exist other manifesta- tions of this disease, such as scars round the mouth, prominent frontal eminences, etc. A very common condition, too, in the J'|'*y''**Ny«*-*»»fc^,44^ subjects of secondary interstitial keratitis, \ 1 11 r J is a peculiar state of the incisor teeth, ^^ ^^'^'\y to whicli attention was first called by Fig. 63.-Hutchiusou'.s Hutcliinson, by Avhom it is also con- teeth, sidered a manifestation of inherited syphilis. The cutting edge of the tooth, instead of being straight, is arched or notched in a more or less semicircular form, the sides being longer than the centre (Fig. 63). Sometimes the form has not become definitely esta- blished at the time of examination, but there is often to be seen an indication that the cutting edge of the incisors is thinner than in the normal condition, and at the same time devoid of enamel. It is the wearing away of this portion which gives rise eventually to the characteristic notch. Another complication is deafness, Avhicli appears in part due to a similar interstitial inflammation of the tympanic membrane, and in part to a periostitis within the channel for the auditory nerve, which probably causes the nerve to become involved in the inflammation. In severe cases more diffuse choroiditis, as well as staphylo- matous i)rotusions of the anterior part of the choroid and the ciliary region of the eye, occur. When the corneal opacity is very dense, it may sometimes not be very easy to ascertain Avhether or not any serious comi)lication exists. As a general rule, it is not difficult, after a little practice, INTERSTITIAL KERATITIS. 169 to satisfy oue's-self as to whether the visual acuity answers to the opacity or not. Even the very densest corneal infiltration pro- duced by this disease should permit of the movements of the hand being seen close to the eye, so that if vision is further reduced there is certainly some complication present. In un- complicated cases, too, the field of vision is of course of normal extent. In a large majority of cases of interstitial keratitis the opacity eventually clears up entirely, or leaves but the faintest trace, discernible only on oblique illumination. Although no ulcera- tion takes place, there may occasionally be a kind of necrosis of the cornea (keratomalacia), leading to perforation. The pro(jnosis depends, in fact, on the severity of the primary affection. When the iritis is slight, and no choroiditis or staphylomatous [)ro- trusions make their appearance, it is good, even though the opacity should be at one time extremely dense. Occasionally cases beginning as interstitial keratitis go on slowly to shrinking of the eye. Sometimes two or more attacks may occur in the same individual at considerable intervals of time. The disease runs a definite course, and it is very doubtful, just as in the case of other deeper uveal affections, how far any treatment is of any avail. The eyes should certainly be [pro- tected from strong light by means of dark glasses, and the patient not allowed to read. When there is much circumcorneal injection the pupil should be kept dilated wdth atropine, so as to avoid the worst consequences of a complication with iritis. Attention to the skin and to the health generally, moderate exercise, and the use of syrup of the iodide of iron internally, either alone or combined with a little iodide of potassium, are indicated. In the distinctly syphilitic cases mercurial prepara- tions may be tried. When ciliary staphylomata develoji, it is advisable to try eserine, which appears to have some influence in preventing their extension. All surgical interference, even such a simple measure as paracentesis, should be avoided, except in cases where there is a marked shallowing of the anterior chamber. In these iridectomy should be performed as soon as possible. Other less characteristic and altogether much less frequent forms of secondary keratitis are met with, in connection usually with old-standing cases of choroiditis and irido-choroiditis. In these the prognosis is relatively much worse than in what is usually known as interstitial keratitis, owing no doubt to there being less tendency towards the healing of the primary process on which they depend. A few cases of interstitial keratitis afterwards become 170 DISEASES OF THE CORNEA AND SCLERA. a-ssociated witli a tul)(.'rculous-lookin^ (leiH).sit in the anterior chamber and iris, as avcU as a (k-nsc whitisli opacity in the corre- sponding portion of tlie cornea. The affection is then extremely chronic, and is of a tuberculous nature, and alUed to, though by no means tlie same affection as, granuloma of the iris. It is very ])rolialtle that many of the less severe cases are also tuberculous. Neuro-paralytic keratitis. — When the fifth nerve is jiaralysed there is a tendency for the cornea to become inflamed. Different forms of intlaminatiou may occur under such circumstances, Avhicli all, however, exhibit, besides the accompanying anaesthesia, a marked slowness in healing, if indeed they do not lead to the total destruction of the cornea. The main cause of so-called neuro-paralytic keratitis is the greater vulnerability of the cornea. The prcM/nosisi in all cases of neuro-paralytic keratitis is neces- sarily bad. The treatment consists in as far as possible protecting the eye from external inffuences, by keeping it tied up, and frequently applying antiseptic lotions. The corneal changes which are met with in herpes zoster frontalis may be looked ujion as neuro- paralytic in their nature. In some cases a number of small herj)etic blebs form on the cornea, very similar to those met with on the skin. These burst and leave infiltrated margins, and eventually more or less opacity. In other cases the first appear- ance in the cornea is of one or more infiltrations or ulcerations. The affected portions of the cornea are generally anaisthetic, and often remain so, long after healing has taken place. A corneal complication appears to be met with in about one-fourth of all the cases of herpes zoster frontalis. According to Hutchinson, the cornea is only affected when an eruption at the side of the nose indicates a participation of the naso-ciliary branch in the affection. This connection is certainly frequent, and in my own experience it has been invariable ; but cases are on record where the cornea has been affected without the skin of the nose being implicated, while at the same time the skin of the nose has been found to l>e affected and not the cornea. Non-Inflammatoey and Degenerative Changes in THE Cornea. Transverse calcareous film.— A very curious form of corneal opacity occurs, mostly in eyes which are at the same time the site of some old-standing inflammatory changes, such as chronic iritis with occlusion of the pupil, and it may be, Avith calcareous CALCAREOUS FILM. 171 degeneration of a cataractous lens. This consists of a transverse film running across the cornea, always at that part which corre- sponds to the half-closed lids. It generally begins at the corneal margins, and spreads from both sides towards the centre. The breadth of the band is tolerably uniform throughout, being in different cases from about |^ to ^ inch. The opacity is finely punctiform, and varies in colour from a grey to a jiretty pro- nounced yellowish brown. Examined with a magnifying-glass, it is found to be composed of a number of granules, which are very regularly distributed and of much the same size throughout. Its edges are very shar})ly defined, and do not anywhere merge into the healthy cornea. It is often least dense at the centre of Fig. 64. — Transverse calcareous liaiid of cornea. the cornea over the pupil, but altogether much more intransjjarent than its appearance at any distance would lead one to suppose, owing probably to the calcareous degeneration which takes place in the deposited matter. There is rarely any disturbance of epithelium above the opacity. This form of opacity almost invariably occurs in both eyes, though it may exist to a much more marked extent in the one than the other at the time of examination. It is met with at all ages and in both sexes. The opacity forms very slowly, and then remains for an indefinite time stationary. The surrounding cornea is as a rule perfectly healthy, but there is a variety of the same affection which makes its appearance in old-standing 172 DISEASES OF THE CORNEA AND SCLERA. leucoinata. From the fact that some form of uveitis is ahnost always found to be associated with it, it seems jirobable that, even when the disease is a]>i>arently primarily a corneal one, there is nevertheless some deep-seated attection, which, though it may escajHj observation at the time, afterwards develoi)s into something more manifest. Glaucoma is often met witli, sooner or later, in connection with these calcareous films in the cornea. Any treatment, such as scraping away the film or removing it by means of very dilute nitric acid, is of very little permanent use, ;vs it again dcvelo[)S. Arcus senilis. — This is a whitish and generally eventually completely circular opacity, which extends round the margin of the cornea in old people. It begins at the upper and lower margins of the cornea, and ' varies considerably in thickness in different individuals as well as often at different parts of the cornea. Very often the arcus is separated from the scleral margin by a clear or le.ss opaque strip of cornea. The ai)pear- ance is due to fatty degeneration of corneal cells. Wounds through this area of degeneration heal much as in the normal cornea. Conical cornea. — Owing to a thinning of the central portion of the cornea, a change of its curvature may take place, whereby the normal ellipsoidal form becomes converted into one more resembling a hyperboloid of revolution. The curvature of the central i)ortion becomes greater, that of the peripheral portions less, than normal (see Fig. 65). This gives rise to myopia, and to a degree of irregular astigmatism with polyojiia. The apex of the conical cornea always lies slightly below the centre, and is often more or less opaque. It may be so thin that it can be seen with the ophthalmoscope to pulsate synchronously with the pulse. The condition is amost invariably bilateral, though frequently not developed to the same extent in both eyes. The pathology is not known. The conical bulging begins generally after jjuberty, in the early years of adult life. It is not im- probable that the degenerative change in the cornea may go on for some time before the bulging begins. There is a decided tendency for the condition to remain stationary after having progressed for some time. I have seen several cases where the condition has lasted for upwards of thirty years without destroying sight, or indeed rendering reading altogether impos- sible. Not infrequently, however, the protrusion gradually in- creases, and is associated with more and more opacity. The diagnosis of conical cornea is made without difficulty by mere inspection when the protrusion is pronounced. The conical KERATOCONUS. 173 shape can be readily seen by looking at the cornea from the side. When slight, or only beginning, it is diagnosed by means of the ophthalmoscope or Placido's disc. With the ophthal- moscope a peculiar circular-shaped shadow is thrown on the fundus, which alters its position with the movement of the mirror. It corresponds to a zone through which fewer rays pass to the observer's eye, owing to the rays on one side of the zone being convergent and on the other divergent as they emei'ge from the eye. With Placido's disc the great diminution in the size of the image of the rings on the apex, and their Fig. 65. — Conical cornea. elliptical or hy|)erbolic distortion in the vicinity of the apex, is very characteristic. Treatment. — Conical cornea admits generally of some, though rarely of very complete, o}ttical correction. The higher numbers of negative spherical and cylindrical lenses, either separately or combined, are those which are most likely to prove of service. Sometimes a steuopaic ajterture or slit may be added with advantage. In many cases the possible optical correction is so small that some operation is indicated. All operations which have been devised for conical cornea are more or less doubtful in their results. Removal of an elli])tical portion from the apex, or from near the ajiex, of the cone has been recommended. In suitable cases there is no better or simpler operation than 174 DISEASES OF THE CORNEA AND SCLERA. that of iiroducing a nebula of the apex with the actual cautery. This iiel)ula may afterwards be darkened by tattooing it with Indian ink. Tliis proceeding always causes iniprovenient in all cases iu which vision is found to be better when a ring- shaped stenopaic ai)erture is held in front of the eye. Another form of misshapen cornea is what is called kerato- globus. In this condition, which is not nearly so common as conical cornea, and i)robably always congenital, there is a more general thinning, and consequently a more globular distension, of the cornea. Examined with a Placido's keratoscope, there is little or no distortion of the circular rings. The cornea is some- times so thin, that when paracentesis is performed it falls in. Fio. 66. — Dermoid cyst of cornea. crum[)led up like paper. No treatment is likely to be of much avail. Tumours of the Cornea. Dermoid cyst. — This may be found as a congenital growth at any }jart of the margin of the cornea. It seems usually to remain of much the same size during life, though occasionally found to increase after birth. The cyst is firmly attached to the cornea by half, or rather more than half, of its base, the other portion being attached to the e}>iscleral connective tissue. A dermoid cyst of the cornea, owing to its position and size, seldom interferes with vision, but may require removal on account of producing more or less conjunctival irritation, or on account of its unsightly appearance. MALFORMATIONS. 175 Fibroma of the cornea. — This is a rare affection. It occurs as a flat growth of densely white appearance, involving the superficial portion of the cornea, over the whole of which it very slowly spreads. When met with before it has involved the whole cornea, it should be removed by slicing off layer after layer, until the transparent tissue below it is reached. Malignant tumours of the cornea rarely occur j)rimarily. They usually either involve the cornea by extension from the deeper tissues of the eye (ciliary body, choroid, etc.), or from the conjunctiva, in which case only the superficial layers of the cornea are implicated. The principal forms met with are sar- coma, generally of the melanotic type, and epithelioma. Owing rt-r^TT'*^^ Fig. 67. — From a case of corneal fibroma. to their loose attachment to the cornea, they may easily be scraped off, but the tendency to recur usually necessitates re- moval of the eye. Congenital malformations of the cornea are rare, unless we include under such, corneal astigmatism. Sometimes the cornea is much smaller than normal, a condition known as microcornea ; in others it is much too large — macrocornea. Both these devia- tions are most frequently accompaniments of more general de- formities, — iiiicropldlialrnos and macroplithalmos respectively, — though they may exist alone, or at all events constitute the most evident deformit}'. A congenital o^jacity of the cornea, either partial or complete, is also met with vei-y rarely. 176 DISEASES OF TTTE CORNEA AND SCLERA. Injuries to the cornea. --Siii)erfi(ial aluasions of the cornea, wliich nurly iiivuhe inore than the epitht'Uuni, are frequently met with. An injury of this nature may result from a scratch from the finger-nail, or from the eye being struck with some object, — e.//., the branch of a tree, end of an umbrella, etc., — or from the rubbing of some small foreign body which has remained for some time in the conjunctival sac. The corneal abrasion, owing to the irritation which it causes of the numer- ous delicate nerve filirils, always gives rise to very considerable pain, often accompanied at the same time by the sensation as if a foreign body were present in the eye. When the abrasion is large it may be followed by a form of recurrent bullous keratitis (see page 1C4). The pain is at once allayed by cocaine, and the treatment consists in using frequently some mild antiseptic wash, so as to avert any possible subsequent inoculation of the wounded cornea. The extent of a superficial abrasion of the cornea may be made very apparent by dropping a drop or two of a half per cent, solutiou of fluorescine into the conjunctival sac, and washing away the excess with water. The area of the abrasion is thereby coloured a vivid green, while the rest of the cornea on which the epithelium is intact remains uncoloured. W(iunds of the cornea are frequent. They may be caused by cutting bodies, directly, or by severe blows. In the latter case a rupture usually takes })lace, not of the cornea itself, but of the globe, at or near the corueo-scleral margin, and roughly con- centric with it. Direct injuries to the cornea may or may not cause perforation. The latter are of course on the whole the more serious. In both cases, however, a good deal depends on the nature of the body with which the injury has been inflicted. It is well, therefore, always to get as trustworthy an account of the accident as possible. Curiously enough, this is sometimes not easy, as either the patient himself or his friends not un- frequently try to conceal the circumstances of what they feel was an avoidable accident. I have seen the cornea more or less seriously injured by almost every conceivable thing — knives, scissors, forks, hair- ]»ins, needles, nails, glass, crockery, curling-tongs, bits of metal of all kinds, animals' teeth, claws, horns, children's nails, bits of wood, and many others. The first consideration will then necessarily be, was the substance likely to be clean, from a surgical point of view, or nof? A wound may be comparatively trifling in itself, — merely, it may be, amounting to a slight epithelial loss, — but sei)tic matter may have been introduced, and WOUNDS. 177 unless antiseptic precautions have been taken in time, serious consequences may result. ]\Iuch depends also, of course, on tlie state of the conjunctiva and mucous membrane lining the lachrymal sac. In the more superficial wounds of the cornea, it is a good plan, in addition to using antiseptic bathings, to clear away any epithelium which may have been destroyed, though not shed, in the vicinity, thus leaving a clean surface. After efficient bathing, the wound may be dusted with iodoform and the eye bandaged. In deeper non-penetrating wounds, the more or less complete adaptation of the lips makes it difficult to disinfect properly. In such cases, the proper thing to do is to treat the case at first in the same manner as if it were quite superficial, but keep the patient under observation for a day or two, in case any decided evidence of a septic inoculation should show itself, when it is necessary to destroy the area of the wound with the thermo- or other cautery. Even at first, when the history of such an accident shows that it was caused by a dirty instrument, it is well to disinfect as actively as possible, using for this purpose chlorine water applied with a camel's-hair brush. Perforating wounds of the cornea do more or less harm, alto- gether independently of the question of whether septic matter has been introduced into the eye or not, according to their site, shape, and extent. Small clean-cut wounds, made by some sufficiently aseptic body, heal very rapidly and leave little scar, if they are linear and not too oblicpie. The apposition of the lips of the wound is then good, and ordinary antiseptic precau- tions, and tying up the eye for a couple of days, is all that will be required in the way of treatment. If, in addition, they lie beyond the pupillary area of the cornea, the prognosis as regards vision is good, always supposing that the lens has not been injured at the same time. Larger linear wounds, even if they are got to heal without any prolapse of iris taking place through them, always leave some defect. The defect is greatest if they are central, and is caused not only by the cicatrix, which, under favourable conditions of healing, may be astonish- ingly slight, but by alterations of curvature, which become permanently established in the pupillary area of the cornea — irregular astigmatism. The treatment of prolapse of iris is elsewhere discussed. With regard to wounds, however, it must be remembered that, inasmuch as they are more likely to come under observation shortly after their occurrence, it is more often possible to replace the prolapse. The thing to aim at in the treatment is to get good apposition of the lips of the wound ; 12 178 DT8KASES OF TlIK CORNEA AND SCLERA. and the usual point wliifli will have to be considered in any case is, as to whether this sliall be got by replacing the pro- lajised iris or by removing it. The decision on this ])oint should be influenced by the degree of injury which the prolapsed iris has suffered, as well as by the nature of the body, in regard to probable asei>ticity, which has caused the accident. Further, when attempts are made to reduce the hernia, a good deal must dei)end upon the ease with which this can be done. In clean- cut wounds, especially linear wounds made with a clean instru- ment, or in cases in which the cornea has burst without anything having come directly in contact with it, it is justifiable and generally easy enough to rei)lace the iiis. In dirty, ragged, irregular-shaped wounds, on the other hand, the jirolapsed iris must l)e sacrificed, or, if the case be seen some days after the accident, left, and removed later in the manner already re- ferred to. Small particles of dust, coal, or metal, and husks of grain, are very liable to become embedded in the cornea. The distance to which they enter depends on their size and shape, and the force with which they are driven against the eye. In most cases the foreign body lies superficially in the corneal epithelium. In the case of small })ortions of metal it very often happens that the cornea is not only wounded, but at the same time slightly burnt, owing to the piece of metal being hot at the time it strikes the eye. These, which are popularly called "fires," difter from other foreign bodies by being as a rule less firmly embedded, owing to the destruction of the immediately surrounding tissue. A brownish ring is often left, too, after their removal, partly an eschar and i)artly rust, which, if not scraped away, is some days in falling off. Usually a foreign body gives rise to sudden pain when it lodges in the cornea, and often more or less pain re- mains until it is removed. The i)ain is more especially com- ])lained of on movement of the lids over the cornea. Excei)t, too, in the case of smooth and chemically non-irritating sub- stances, the eye becomes rapidly injected, and the i)atient sufters from photo] )hobia and lachrymation. Husks of grain become endjedded with their concave surfaces towards the cornea, and the lid i)assing over their smooth surfaces does not give rise to much pain. The first point to attend to in removing bodies from the cornea is to use an aseptic instrument. The best form of instrument to use is a corneal spud, either smooth or, preferably, grooved. But any sharp-pointed knife will do, and in the case of deei)-lying foreign bodies may even be more suitable. FOREIGN BODIES. 179 Another point to be attended to is to take care to avoid scrap- ing away any more of the corneal epithelium than necessary. The spud or other instrument must, of course, be dug in as far as is re(j[uired to remove the foreign body. But one's attention must be confined to the one place at which the body is lodged. Too much scraping about in the vicinity must be avoided. To work with the least risk of unnecessary scraping, the patient's head and eye must be properly fixed. The best way to do this is to seat him on a chair facing a good light, or, if the operation is performed after dark, in such a way that an assistant is able with a convex lens to con- centrate a beam of candle or gas light on the cornea. Then, standing behind him, with his head leaning against the operator's chest, the lids are held apart with the fore and middle fingers of the left hand. These fingers should be pressed against the margins of the lids, otherwise it is not possible to counteract pi'o- perly any eftbrts that the i)atient may make to close his eye. At the same time, by slight pressure of their points on the globe itself, above and below the cornea, one may sufti- ciently control its movements. Cocaine renders it possible to remove foreign bodies without causing ])ain, and also generally ensures steadi- ness on the part of the patient, so that it is seldom that any particular skill is required in the operator to enable him to confine his attention to the foreign body, and not wound any other part of the cornea. The main difficulties, when the precautions mentioned have been taken, are associated with the re- moval of deep-lying bodies. Sharp, irregularly- Yl(^. 68.-Corueal shaped small pieces of stone or metal often lie spud, deeply embedded, and in a track which passes ol)liquely into the corneal substance. There is some danger of })Ushing such bodies through into the anterior chamber. A sharp-cutting fine knife or needle should be used to open uj* the track well before any attempt is made to push a spud in behind the body. The subsequent treatment of a case in Avhich a foreign body has been removed from the cornea should depend upon the depth and appearance of the wound which is left. In the majority of cases, taken in time, all that is required is to keep the eye 180 DISEASES OF THE CORNEA AND SCLERA. clean for twenty-four hours with boracic acid lotion. Other cases may have to be treated on the lines already laid down in connet'tion with corneal wounds. Deposits in the cornea. — Some metallic salts, used in solution as lotions for the eye, may leave deposits in the cornea. This danger is greatest with lead lotions, which should never be used where the cornea is inflamed. A white de])osit of lead is very rapidly formed on the surface of a corneal ulcer, and may often occasion much greater defect of vision than avouM arise from simi)le cicatrisation. As such lead de[)0sits are generally super- ficial, some im})rovement may result from scraping them away. Nitrate of silver, in the same way, may lead to an opacity, but this is not nearly so unsightly, being a de})Osit of a number of more or less closely packed l)rownish or black dots. A much more prolonged use of this substance is required, too, to produce much staining, than is the case with lead lotions. Sclero-corneal ruptures. — When the coats of the eye are rup- tured by a severe blow, the line of rupture is most frequently roughly concentric with the margin of the cornea, and from 1 to 2 mm. distant from it. The eye, in fact, gives way close to the true corneo - scleral junction at the angle of the anterior chamber. Such ruptures are usually in the upper portion of the corneo-scleral junction, but may be in any part of it. They rarely involve the ciliary body. When large they may permit of the escape of the lens, and it is in this way that a subconjunctival dislocation of the lens takes place (see p. 231). The vitreous, too, and even the retina, may be propelled through an extensive rupture of this nature. A less extensive wound generally gives rise to quite a characteristic appearance ; a portion of the iris becomes prolapsed into it, so that the centre of the pupil is drawn to the w^ound, and an apparent coloboma results. The conjunctiva which remains intact is often raised, too, in the form of a bleb over the wound, by aqueous humour infiltrated below it, and the escajte of aqueous in this manner leads to a marked shallowing or abolition of the anterior chamber. Owing, no doubt, to the integrity, as a general rule, of the conjunctiva, corneo-scleral i"ui)tures are rarely followed by severe inflammation. On the other hand, they seldom heal without leaving a great deformity. This is due to the separation of the lips of the wound by prolapsed iris, etc. On this account they usually call for operative treatment. In fresh cases an opening should be made in the conjunctiva a quarter of an inch or so behind the rupture, and parallel with it. The conjunctiva should RUPTURES. 181 then be undermined, so as to form a flap, which can be lifted away from the wound. When tliis has been done, tlie prolajjsed iris is removed as comi)letely as possible, so as to admit of the edges of the wound coming in contact. The conjunctiva can then be carefully stitched over the wound. There is rarely any use trying to replace the prolapsed iris, as it is generally lacerated as well. In cases which have been allowed to heal after the accident, and which have resulted in great deformity and corre- sponding interference with vision, a method of operating advo- cated by Xuel would seem to offer the best chance of improvement. It consists in making a section with a narrow knife, reopening the scleral wound, and then drawing the surrounding conjunctiva over this opening l)y means of a special suture. The object of the operation is to cover the wound with as thick a layer of superficial tissue as possible, and thus permit of the proper re- establishment of the anterior chaml^er. To effect this the knife, after cutting through the deep cicatricial tissue filling up the space between the lips of the wound in the sclera, is directed backwards, so as to cut out a deep Hap of conjunctiva. A con- junctival suture is then introduced in the following manner : It is entered at the equator of the eye, as far back as possible, and passed out and in, or run through the conjunctiva for a considerable distance, parallel with the corneo-scleral margin. The needle is then carried diagonally over to the conjunctiva immediately surrounding the cornea at the opposite end of the wound, and the thread run in a similar manner close to the cornea, and finally brought out beyond the wound at the other side. The two ends of the thread are then tied tightly together. In this way a large mass of conjunctiva is puckered up over the wound, in a much more efficient manner than could be done by the introduction of a number of sutures in the ordinary way. Operations for corneal staphyloma. — When a partial staphy- loma of the cornea becomes unsightly, it may be reduced in size by the following simple operation. A cataract needle is intro- duced through its base, and held in one hand. An elliptical piece of the cicatricial tissue of which the staphyloma is com- po.sed is then cut out by making one incision at the one side of the needle with a narrow cataract knife, and another from the other side converging towards the first, and in such a manner that the portion held by the needle, and consequently the needle itself, is cut out. This can be done very quickly. Antiseptic precautions should be taken and a firm bandage api^lied. In cases of more complete staphyloma, attempts have been made to retain a better stump by covering up the wound result- 182 DISEASES OF TIIK CORNEA AND SCLERA. iiig from tlie reinov.il of tlie i»r()tiu(liiirouglit out near to the first puncture. The jn-o- trusion is then cut oft" by transfixing it through the middle, and cutting outwards, then seizing the end of the fiap thus formed and removing the rest with scissors. As soon as this has been done, the two ends of the continuous suture are drawn together and firmly knotted (see Fig. 69). The effect of this is to draw the conjunctiva over the wound, and thus prevent the escape of the vitreous ; the lens generally escapes with the removal of the protrusion ; if it does not, the capsule may be scratched so as to permit of its escape. It is of the utmost importance that antiseptic precautions should be taken in this operation. The thread mav l)e allowed to remain for a week at least. If it cuts TATTOOING. is: tlirougli at any pai-t, a fresh stitch may be used for bringing the coujuiictiva together where this takes phice. The most suitable operation for cases of complete staphyloma is evisceration of the globe. Tattooing of the cornea. — This may be done either with the object of removing the unsightly appearance of a dense leucoma, or to improve \asion. In the latter case it may or may not be combined with ii'idectomy according as the whole pupillary area is covered or not by the cicatrix. Central nebulaj which do not entirely cover the pupil may, nevertheless, cause considerable visual disturbance l)y scattering the light which passes through them into the eye. By blackening a nebula with Chinese ink this dis- turbance is in great measure removed. The same advantage may be got by tattooing Avhen, whilst some clear cornea remains, a nebula is sufficiently extensive to call for a displacement of the pupil by iridectomy. The rays which then pass through the artificial pupil are more effective when the scattered light has been stoi)ped. Tattooing may be done either with a single grooved needle (Fig. 70) or with a bundle of finer needles held together in a special holder (Fig. 71). Often it is useful to use both: beginning the blackening with the former in- serted obli<|uely at points close to each other all round the area to be stained, and then continuing it by making several stabs with the latter instrument over the enclosed space. As thick a watery suspension of the ink as pos- sible should be used. This is carried into the cicatricial tissue with each prick 1)y the grooved needle, and dabbed on to the surface with a camel's-hair brush after the stabbing with the bundle of fine needles. The operation is painless under cocaine, and seldom causes much subsef[uent irritation. It is, however, generally necessary to repeat the process once or twice, at intervals of a few days, before the desired degree of blackening is obtained. It is im- portant to remember that the eye must be steadied only with the finger tips, not fixed with the forceps, as the ink getting into the wound in the conjunctiva made by the teeth would leave a stain there. Scleritis. — Infiammation of the sclera is confined to its Fig. 70. Fk!. 71. 184 DISEASES OF THE CORNEA AND SCLERA. anterior jiart, wliicli is covered by conjunctiva. Scleritis may occur in circumscribed patches, or may be ditt'used in tlie sliape of a belt round the cornea. Tlie former is usually more .super- ficial and uncomplicated, the latter deeper and coni])licated with corneal infiltration, irido-cyclitis, and anterior choroiditis. It is common to distinguish the superficial cases of infiammation as cases of ejiisclerifis. This, though a useful clinical distinction, cannot always be made, as the su])orlicial infiammations pass by insensible gradations into the deep forms, to which the name selerif/'s is more generally applied. Superficial scleritis, or episcleritis, is a long-continued disease which is associated Avith very varying degrees of discomfort. In Fig. 72. — From a case of sujierficial scleritis. some cases the local .subjective symptoms are so slight as to give ri.se to little or no complaint ; in others there is severe jiain. The chronic nature of this afi'ection de{»ends mainly upon the tend- ency that the infianunation has to recur in successive patches at difierent parts of the sclera. Often one e5^e alone may be affected, but not unfrequently the inflammation occurs simultane- ously or alternately in both. Each i)atch of infiltration lasts for a month or two, and is succeeded by another, or it may be two at the same time, after an interval of varying duration. In most cases several months, or even years, elapse between the attacks. In others, again, patch ui)on patch makes its appearance as soon as a preceding one has disa]>i)cared, or even before it is com- pletely removed. The new patches almost invariably appear at SCLERITIS. 185 some new point, the cicatricial site of a previous patch not being again attacked. The actual patches vary in size, being usually somewhere between a quarter and a half of the diameter of the cornea across, and approximately circular. The scleral infiltra- tion causes a firm swelling, which is often sensitive to touch, and over which the conjunctiva is freely movable. The overlying conjunctiva is always injected, and the area of its injection is greater, sometimes much greater, than that of the scleral infiltra- tion. The infiltration is itself, at the height of the process, Fig. 73.— Old stainlins; scleritis. densely vascularised. Its vessels as seen through the conjunc- tiva have a darker, more purplish, hue than the supei'ficial ones. When alxHorption has taken place, which it always does even- tually, the patch never Ijreaking down and ulcerating, a more or less definite alteration is left at the spot occupied by the infiltra- tion nodule. The swelling caused by the infiltration, which in many cases may ])C most pronounced, gradually subsides, leaving a cicatrix, to which the overlying conjunctiva becomes adherent. The site of this cicatrix, as seen through the conjunctiva, has always a more or less slaty-looking colour, described sometimes as porcellaneous-looking. Owing to patches of this kind being ISO DISEASES OK THE CORNEA AND SCLERA. left, it is seldom dirticiilt to recoj^nise a case in which there has at one time been an attack of superficial sc'leritis. Episcleritis patches, which are situated fairly close up to the margin of the cornea, might i)ossibly be mistaken for hyperplastic conjunctivitis (spring catarrh), or for a focus of phlyctenular conjunctivitis. The ditlcrential diagnosis presents little difficulty, however. Scleritis patches are never found (juite at the corneo- scleral margin, as in the case of the hyperiilastic tissue of spring catarrh. Besides, the conjunctiva is moval)le over the jiatch ; while, in contradistinction to the jihlyctenular type of inflamma- tion, they never break down and ulcerate. The only excejjtion to this occurs in cases in which the scleral patches are tuberculous. Fig. 74. — Ulcers of the seleni, t'roiu :i case of tuberculous scleritis. The nodules may then break down and form deep ulcers, as shown in Fig. 74. Sujierficial scleritis occurs in both sexes with about equal frecpiency. There is no known definite cause for this disease. The individuals aftected are generally middle-aged.. They are often rheumatic, and sometimes gouty. But in how far these conditions are mere accidental concomitants, or are of any real causal significance, is not by any means certain. The treatment is on the whole unsatisfactory. Some recom- mend large doses of the iodides ; others believe that subcutaneous injections of pilocarpine do good. My own experience of both these remedies has not been particularly encouraging. Sub- conjunctival injections of corrosive sublimate solutions into the SCLERTTIS. 187 scleral infiltrations have been vaunted in some quarters. Any action that they may have appears to me to be due entirely to the mechanical dispersion which the liquid may eftect. I have in some few cases used them, but have got equally good effects with the injection of sterilised water, which has the advantage of being much less painful. Massage has also been emj)loyed, and is undoubtedly useful. The area of swelling is rubbed through the lid for half a minute or so at a time two or three times daily. This seems to help in the dispersion, and promotes the absor})tion of the infiltration, and may even be combined under cocaine with the sterilised-water injections. I liave also tried incising the patches and scraping with a small Volkmann's spoon. But the treatment wliich has yielded me the best results, and which I now adopt in all cases, is free cauterisation of the in- filtrated nodules with the thermo-cautery. This seems not seldom to cut short an attack. After recovery from one attack, salicylate of soda may be tried, and continued for some time. Baths seem also to do good in preventing re- currence. Harrogate, Ikixton, Homburg, and Wiesbaden are those of which I have most ex- perience in this connection. Wiesbaden has on the whole given the best results. Deejjer scleritis, with its attendant comi)lica- tions, is altogether a more serious disease. Eti- ologically it is just as obscure as the more super- ficial affection. Both eyes are almost invariably attacked in the typically deeper-seated inflammation. It is therefore not unlikely that the disease may stand in close relation to tuberculosis and inherited ^^9; 75.— Small syphilis, which are often found to coexist in those spoou, ' used suffering from it. In causation it would ajtpear for lenioving as if it were closely allied to the usual form of corneal ami . . . . -^ . scleral luhl- mterstitial keratitis. It more generally occurs in trations. young people : mostly in young women. In them it is undoubtedly frequently associated with menstrual disturb- ances, as well as with definite uterine and other complaints, which call for sjiecial attention. Dee}) scleritis is more i)ersistent than episcleritis. In it there are not such marked periods of intermission. The deeper and more wide-spread inflammatory infiltrations of the sclera lead eventually to weakening of that coat, and cause it to yield to 18S DISEASES OF THE CORNEA AND SCLERA. the iiitra-ociilar j)reasiiro. There i.s thus formed a stapliyloina of the sclera, in, or in tlie neiglibourhood of, the ciliary region. The vision suffers from an infiltration of the cornea, by extension from the focus or foci in the sclera, or by iritis, witli its attendant sequela?, and anterior choroiditis, the so-called sclero-rhoroiditis anterior. Often these different com{)lications exist together. In cases which have lasted for a long time they almost invariably do. In addition, the intra- ocular tension may increase (secondary glaucoma), and vision may in this way be altogether destroyed. The infiltration which invades the cornea does not clear away, l)ut causes a dense por- cellaneous white intransparency, to which the name of sclerotising keratitis is sometimes given. Fortunately deep scleritis is very much less common than episcleritis, as its treatment is even more unsatisfactory and often well-nigh hopeless. Apart from the local treatment which may be required for coexisting uterine and other disorders, and from the exhibition of drugs from which little is to be expected, iridectomy should usually be tried. I believe it is of advantage to perform iridectomy early in the cou.rse of this disease. Iri- dectomy may certainly cause a retardation of the process, or may at all events delay the worst consequences of the more severe complications. If only resorted to, as some recommend, after the sclera has yielded and become staphylomatous, it is less likely to be of use. In cases wdiich first present themselves at this stage, sclerotomy is a safer and more suitable operation. CHAPTER VIL DISEASES OF THE CRYSTALLINE LENS. Several changes take place in the lens during life. In the young it is perfectly colourless ; later on in life it is yellowish. The change in colour is accompanied by an alteration in con- sistency, bringing with it a diminution of elasticity, which is the cause of the gradually diminishing amplitude of accommodation met with as age advances. The slaipe of the lens is much more globular in infancy and childhood ; the increase which takes place is therefore mainly at the equator. In this way, too, the dioptric value of the lens accommodates itself to the change which takes place in the length of the eye as it increases in size. The growth of the lens (which, being derived from the cuti- cular epiblast, is analogous to that of the cuticle) goes on throughout life, and does not cease with the attainment of adult life. From 2-5 to 65 its weight and volume are increased by one-third, and its diameter by one-tenth. The fibres are arranged in lamella?, and towards the centre of the lens are more compressed than the superficial ones, and contain less water, but never any keratine. There is a gradual increase in the density, and consecpiently in the refractive index, of the different lamella? passing from the surface to the centre of the lens. This difference becomes less marked, as age advances, by the gradual development of a hard central jtortion, the so-called niKleus, which becomes apparent about the time, or shortly after the period, of full growth, and slowly invades the more superficial portions of the lens, the refractive index of which, corresponding to the greater density, is increased. The refractive index of the superficial fibres of the lens differs but slightly in the eyes of young individuals from that of the aqueous humour. The increase in their refracting ])ower, which comes on with age, brings about, however, a considerable difierence. The reflection of light from the surface of the lens in old peojile. 190 DISEASES OF THE CRYSTALLINE LENS. which tliis abrupt chaiiife in refractive power admits of, is the cause of the greyisli auil semi-opacjue appearance of the pujnl whidi is so frecjueutly observed. The capsule of the lens is a highly elastic, and to all a|i}>ear- ance homogeneous, membrane, which attains its greatest thick- ness at the anteri(jr portion. Wliile the lens fibres are known to be histogcnetically epithelial, it still remains doubtful whether the capsule is originally an epithelial or a connective tissue. The latest investigations indeed seem to point to a douljle origin. The anterior portion of the cajisule — what is usually spoken of as the anterior aijiside — -is covered on its internal surface by a single layer of epithelial cells, which jtlay an imjiortant part in the physiology of the lens. The normal position of the lens is that in which it is sus- pended at an equal distance all round from the circular ciliary body, so that its axis is nearly, if not absolutely, centred with that of the cornea. The centre of the anterior sui'face lies in the same plane as the iris, while the equator, owing to the curvature of the surface, is considerably behind that plane. A space is therefore left between the posterior surface of the iris and the anterior surface of the lens. This is the so-called posterior aqueous chaniher. The suspensory ligament of the lens, or zonule of Zinn, has an extensive attachment to the l)rocesses of the ciliary body. Behind the zonule of Zinn, and between it and the vitreous, or more correctly between the fibres of the zonule which pass to the anterior and those which pass to the })Osterior capsule, is a space called the canal of Petit. The intimate structural as well as anatomical connections which exist between the suspensory ligament and the vitreous and anterior portion of the uveal tract, render a |)articipation of that structure in dee})-seated diseases of the eye not infrequent. Cataract. — When the lens, which in its physiological state is transparent, becomes intrans[)arent, there is said to be cataract. The loss of transparency may involve the whole or only a portion or ])ortions of the lens, i.e., the cataract may be complete or partial. Anatomically, we may distinguish two forms of cataract— (1) Lenticular cataract ; (2) ca/tsular cataract. The first form is a result of the intransparency of the lens fibres or true lens substance, the second of the cells lining the capsule of the lens. The two forms may exist together or separately. Clinically, cases of cataract may be grouped with advantage under the following heads : — (1) Senile cataract, Avhich is due to an idiopathic degenerative change in the lens substance, CATARACT. 191 unconnected necessarily with any other condition which leads to an impairment of the functions of the eye; {2) juvenile and congenital cataract, of which there are various forms ; (3) com- plicated or secondar// cataract, in which the opacity of the lens is the result of more or less destructive changes in the deeper parts of the eye ; (4) traumatic cataract ; and (5) after-cataract, or the opacity which remains or Ijecomes developed subsequentl}- to the removal, by artificial or natural means, of the intrans- parent lens. The transparency of the lens is only maintained when no great change takes place in its nutrition. A normal nutrition requires, as a rule, a normal position of the lens, and always integrity of its capsule. The main cause of intransparency appears to be a too rapid or irregular abstraction of liquid, which is favoured by some interference with the supply, or some abnor- mality in the constitution of the nutrient liquid. It is only in eyes where no nucleus has yet formed in the lens, and therefore in the young, that the whole substance of the lens is capable of undergoing a degenerative change which leads to soft cataract. The nucleus may lose much of its transparency from sclerosis and increasing coloration, but it is not the same process of degeneration as takes place in the less altered portion of the lens. Senile cataracts are of two kinds — cortical and nuclear. The former is much the more common. In this form only that portion of the lens which surrounds the nucleus becomes opaque. The colour of such cataracts, when the whole of this portion (the coi'tex of the lens) has become opaque, depends on the size and colour of the sclerosed nucleus, as well as on the degree of opacity of the cortical layers. When the opacity is dense and the nucleus small, a very uniform white appearance is met with : on the other hand, a greyish, and often yellowish, tinge is given to the. cataract by the shining through of a large nucleus. In the first case, the cataract is comparatively soft ; in the second, it is what is called hard. As a general rule, it may be taken that the older the individual is before the cataract begins, the larger is the sclerosed central portion, and the smaller the cortical opacity. An abnormal degree of .sclerosis may involve the whole lens, which in such cases is smaller than normal. This only occurs, as a rule, in very old people, and conies on very slowly. This form, in which no true cortical substance remains to undergo degenerative changes, and yet the sclerosed portion becomes greatly deprived of its transparency, is called nuclear senile 192 DISEASES OF THE CRYSTALLINE LENS. cataract. Often the lens is very darkly coloured, when the cataract is said to be " black." Nuclear cataract is therefore essentially a hard cataract. Ordinary senile cataract, where there is a certain, though varying, proportion of cortical substance, begins apparently as the result of some irregularity in the process of sclerosis of the central portion. The first signs are to be seen in the region between nucleus and cortex. Variously shaped opacities, mostly radiating lines or striaj, which ajj^jear white by reflected and black by transmitted light, occur here ; these gradually become confluent, and extend towards the capsule. This change is often associated with considerable increase in volume, so that the iris is pushed forwards and the anterior chamber shallowed. When the whole cortex has become opaque, the cataract is said to be r?))^. The term has reference to its then being capable of being shelled out of its capsule, to which it is other- wise somewhat adherent. There is considerable ditierence, how- ever, in ripeness taken in this sense, as in some cases, even when the opacity extends right up to the capsule, the adhesion between lens substance and capsule is pretty firm, whereas in others again a semi-opaque lens separates very completely and readily from the capsule. It is not as a rule difficult to make out if the opacity reaches to the capsule or not ; where there is any doubt, the diagnosis may be assisted by observing whether, when a light is held to one side of the cornea, the portion of the iris to the same side throws any shadow on the opaque lens ; if it does, there must be an intervening portion of transparent lens. It must not be forgotten that a similar shadow may be seen in cases of over-ripe cataract. These cases may be diagnosed by observing that the anterior surface is at the same time flattened, whereas the unripe cataract presents a distinctly curved surface. Tremulousness of the iris — iridodouesis — is also frequently met with where the cataract is over-ripe and has undergone retro- gressive changes. After the condition of ripeness has existed for a longer or shorter time, further changes may take place, which are charac- terised as stages of over-ripeness. The opaque cortical substance may to some extent shrivel from loss of liquid, and in this way a little of the sight — as a rule, only a very little — be regained. On the other hand, and much less frequently, the cortex may become more liquid — to such an extent, indeed, that the nucleus moves about in it, and gravitates to the lowest point of the lens. Such liquid cataracts are called Morgagnian. The Morgagnian cataract is easily distinguished, too, by the position of the CATARACT. 193 yellow nucleus which has sunk to the bottom of the opacity. The diagnosis may often be made without dilating the pu[)il, by observing the difference in colour of the opacity when the patient is standing up or lying down. In the former case it is generally yellowish ; in the latter milky white. The time which elapses before a senile cataract becomes ripe varies within very wide limits. It is impossible in any par- ticular case, as a rule, to predict even approximately how long the existing opacity will take to become complete. No regu- larity is shown in the process, which at times advances more rapidly than at others. Some cases, for instance, rapidly advance till a considerable degree of opacity is reached, and then only progress slowly to maturity ; while others advance slowly at first, and, after reaching a certain stage, very quickly end in complete opacity. Probably, however, no cases remain absolutely stationary when once a separation has taken place between the nucleus and cortex, and striae are seen beginning in the region between them. In cases where small opacities are found in other situations, there does appear to be some possi- bility of the condition remaining stationary — at all events for some considerable time. The degree of blindness to which the progressing cataract gives rise depends a good deal on the site of the intransparent portions of the lens. If, for instance, as often happens, the cortical substance in the pupillaiy area is more affected than elsewhere, the vision is more seriously interfered with than where the same degree of opacity exists at another part of the cortex. In such cases vision is better in the shade than when the pupil is more contracted by a strong light, and a temporary benefit may be got by the use of a weak mydriatic. Less frequently, owing to the scattering of the light passing through the lens, or the polyopia which is produced by the formation of separate images by the different segments of the lens, vision is considerably improved under conditions which give rise to con- traction of the pupil, so that some benefit is derived for a time by the use of a miotic or a steno})aic slit. When a cataract is ripe, the vision is, as a rule, reduced to mere perception of light ; but where the opacity of the lens is unaccompanied by any other affection of the eye, this percep- tion is (except in the cases of extremely dense cataracts) very delicate. The simplest way of testing the light perception is to throw light reflected from a gas jet into the eye with the oph- thalmoscope. The room should be darkened and the light be shaded from the patient. By turning the gas down or up it is 13 194 DISEASES OF THE CTvYSTALLTXE LENS. easy to tleU'i-niiiie the smallost amount of light whicli is just distinguishal)k' from the light of the room. Another way which ia often i»racti.setl, and which attbrd.s, too, a means of readily comparing the acuity of the light perception in ditierent cases, is to hold a lighted candle in front of the patient in a dark room, and notice whether he distinguishes between light and darkness when the flame is shaded by the hand or allowed to remain uncovered. Except in the very densest cataracts, the difference should be readily appreciated when the flame is from fifteen to twenty feet distant from the patient's eye. A certain degree of refractive power always remains. The patient should therefore also he able, where there is no comi)lica- tion, to appreciate fairly well the direction from Avhich light falls into the eye. This may be tested by asking him to point out the [)Osition of the flame of a candle, held in succession at ditt'erent parts of the field of vision. A good 2)i'ojection indicates almost always not only a tolerably free field of vision, but also, as the patient directs his fovea to the light, an intact central vision. This loss of all vision, with the exception of light perception, which characterises most cataracts which are ripe for operation, must not always be taken as the criterion of maturity. In some cases of hard cataract there is considerably more vision than this : the patient, for instance, being often able to count fingers close to the eye, so that if one were to wait for complete blind- ness before operating, much time would be lost to the patient. Fortunately, although senile cataract almost invariably afiects both eyes, there is often a considerable time intervening between the time when maturity of the cataract is reached in each eye, so that if an oj^eration be undertaken as soon as the first cataract is ripe, the patient is not rendered absolutely helpless by the disease. When both eyes are pretty equally affected at a stage when most useful vision is lost, an extraction may be undertaken rather sooner than would otherwise be done. Attempts at artificially rii)ening a senile cataract should not be made. Sometimes the anterior capsule of the lens participates in the cataract ; that is to say, the cells lining the inner surface of the capsule proliferate and lose their transparency. A capsular cataract is more especially met wdth in lenses which have become shrivelled and over-ripe. It is rare that the opacity extends beyond the limits of a moderately sized pupil. If the cataract be examined, w'ith the pupil dilated, before an operation is undertaken, the ca^isular opacity cannot well escape detection. CATARACT. 195 It is intensely white, and fiecjuently presents an irregular outline. No certain, constant connection between senile cataract and any other disease has as yet been definitely established. There is an undoubted hereditary tendency, which appears to descend by the male rather than the female line, although the condition is no more frequent in the one sex than the other. Many individuals with senile cataract exhibit no other symptoms of senility ; in others, atheromatous degenerations of the arteries are more or less evident. Diabetes sometimes coexists with senile cataract. In most cases there is probably no connection between the two conditions, although there uncloul:)tedly exists Fig. 76. — Case of incipient senile cataract ; oblique ilhuninatiou. a true diabetic cataract. It has not yet been satisfactorily shown, however, how diabetes produces cataract. Only a very small number of diabetic cases are complicated by cataract, and repeated experiments make it appear pretty certain that the small amount of sugar contained in the nutrient licpiids of the eye cannot be the direct cause. It is more probable, indeed, that the malnutrition and general cachexia give rise to the lenticular opacity in those [)redis],)Osed to cataract, or in whom the conditions are otherwise favourable. Senile cataract is met with in a constantly increasing proportion of individuals living from the age of 50 upwards. After 80 years of age the relative frequency appears to be considerably less. The diagnosis of cataract i)resents no difficulties when no 190 DISEASES OF THE CRYSTALLINE LENS. com plications exist in the anterior portion of tlie eye, such as dense opacities of the cornea, occhision of the pupil, etc. By reflecting light into the eye with the ophthalmoscope, we at once see, in the form of black patches or stride on the yellowish-red background, formed by the light which reaches the observer's eye from the fundus, any opacity or opacities which may exist in the lens, while when the cataract is complete there is an absence altogether of any reflex from the fundus of the eye. If the lens be merely examined by oblique illumination, and not dioptrically with the ophthalmoscope, the senile greyish reflection is apt to suggest an opacity which does not in reality exist, and the transparency of the lens can be at once seen by observing the unbroken reflection of light from the back of the eye. The only treatment by which sight can be restored without too great a risk of destruction of the eye is by extracting the opaque lens. This is, as a rule, preferably done by shelling it out of its cajisule, which must first be ruptured. In certain cases the lens may be removed in its capsule. Operators differ as to the cases in which it is advisable to do this. There can be little doubt, however, that where any evident weakness in the ligament of the lens exists, and, still more, where there is more or less marked subluxation, this is the best operation. After-cataracts form in cases in which the lens capsule has been left in the eye, and these opacities may attain such a density as to render a subsequent operation necessary. The secondary intransparency generally forms after the lapse of some months, and is the result of a proliferation of the cells of the anterior capsule, as well as an entanglement of cortical substance, Avhich has not been removed at the time of extraction, or absorbed during the healing process. Where there is any inflammatory exudation this becomes matted, too, with the opaque capsule, and adds to the density of the screen thus formed. The ojierations required for after-cataract are performed with the view of removing the opaque screen from the line of sight without removing it from the eye. When the main opacity is not in the axis of vision no operation is required. Where severe and prolonged iritis has followed the operation for the extraction of a cataract, there is not only a denser after-cataract formed, but the pupil is drawn up to the wound in the external coats of the eye, \\\i\i the result that the vision is destroyed. If under these circumstances, however, there still remains some AFTER-CATARACT. 197 perception of light, it is possible, by })erforraing the operation of iridotomy, to improve matters. The amount of vision which the patient recovers after such an operation depends greatly on the state of the vitreous. Often it is much clouded by exuda- tion or the semi-organised remains of exudation, which after a time, if there is no fresh inflammation, may clear away to a very considerable extent. There is a great tendency to recur- rence of inflammation, however, after iridotomy, which on this account should not be performed until the eye has come abso- lutely to rest. The opening should be made as large as possible, to prevent reclosing, should there be inflammatory reaction. Fig. 77.— Case showing the result of the operation of irid- otomy in opening up a pupil which had become occluded by inflammatory exudation following extraction. This may easily enough be done when there is some retractile power in the iris, but in cases where the fibrinous deposit behind the iris is dense and tough, and the iris itself altered by in- flammatory infiltration or atrophied, it is often extremely diflicult. In such cases it may be necessary to cut out a triangular-shaped bit of the opaque screen. The simpler after-cataract operations may be done after the lapse of a fortnight from the time of the extraction. But where there has been any marked inflammatory reaction after the first operation, the eye should have been absolutely free from irritation for several weeks before anything further is attempted. With regard to extraction, both eyes should never be o^icrated on at the same time. The reasons are obvious. The operation 198 DISEASES OF THE CRYSTALLINE LENS. is itself a more serious one when both are done. There is the ixtssibility of some unforeseen accident happening, independent I)erliaps altogether of the nature of the operation, and avoidable on a future occasion ; or some unfavoural)le condition, interfering with the success of the first ojieration, may necessitate a modification in the operation for extraction in the other eye. Only a very few instances are recorded where a spontaneous cure of senile cataract has taken ]>lace, owing to absorjition within the capsule. The process is a very slow one, yet one which is sometimes very complete. In one of the cases which have come under my own observation tlie spontaneously cured eye had better vision than the other one on which I had success- fully operated eleven years previously. Probably the infrequency of spontaneous cure depends entirely upon the lapse of time required for it to take place. On this account it need not be taken into consideration in the treatment. No medical treat- ment is known which will promote this natural cure. Occa- sionally a cure is effected by an accidental dislocation of the opaque lens. After an extraction of cataract, the eye does not immediately recover the full amount of sight of which it is capable, but goes on im^iroving from day t(j day for a length of time, which varies considerably in different cases, usually, however, for at least a fortnight or three weeks. The cause of this improvement is to a great extent the absorption which takes place of the cortical matter left in the eye, and consequently it is slower, on the whole, the more incomplete has been the clearing away of the lens substance. In many cases, too, there are slight in- transparencies in the cornea Avhich only slowly clear away completely. After the removal of the lens, the eye is of course left very much out of focus, and becomes highly hypermetropic. The condition of the eye when the lens is absent is called aphakia, and the degree of hypermetropia varies according to the build of the eye and the state of previous refraction. The higher the previous hyi)ermetropia, the higher of course is the aphakic hypermetropia ; whereas, on the other hand, there is less hyper- metro})ia in an aphakic eye, the higher has been the previous degree of myopia. Sometimes the previous myopia has been exactly sufficient to neutralise the refractive change produced by the operation, so that emmetropia is the result, or there may even be some myopia left after the lens has been removed. Much most frequently, however, convex glasses are required before any sharp retinal images are formed ; and as with the LAMELLAll CATA RACT. 199 absence of the lens there is an im})Ossibility of any aeconinioda- tion of the eye, absokitely clear images can, with the same glass, be received from objects at one distance alone. The [iractical result of this is, that at least two different strengths of glasses have to be worn, one for distant vision, and the other for reading. If the eye has been previously enimetro[)ic, the glass which is required for distant vision is usually + lO'O or + 11 "0, while for reading + 14:'0 or+ 15'0 suffices. Vision is often imiu-oved by the addition of a cylindrical lens to the spherical one, as some astigmatism is frequently acquired, owing to a flattening of the cornea in a direction at right angles to the incision. The amount of astigmatisni varies in different cases. The presence and character of a previously existing regular astigmatism will necessarily have an influence in this res})ect. It is some time be- fore complete consolidation of the cicatrix leads to a final shape of the cornea, so that it is not often advisable to pre- scribe the sphero-cylindrical spectacles until the astig- matism has acquired its per- manent degree. There is some difference of opinion as to when spectacles may be worn. Much reading should certainly not be allowed until three or four weeks have elapsed since all redness has disappeared from the eye. Two forms of juvenile or congenital cataract are of common occurrence, namely, lamellar cataract, which is a partial cataract, i.e., one in which the opacity only involves part of the lens, and complete congenital cataract. Lamellar cataract is probably most frequently congenital, although it undoubtedly often makes its appearance in early childhood. In the great majority of cases it exists in both eyes, very rarely in one alone. The degree of visual disturbance which it causes varies very considerably according to the density of the intransparency and the amount of lens substance which it involves. In some cases the density of the opacity is so slight that hardly any defect of vision is produced. In other cases, again, a considerable degree of blindness results from a dense opacity. Between these two extremes all degrees of visual dis- FiG. 78. — Case cif laiiR-lIiu- eutaiact : oljluiuc illuiniiiation. 200 DISEASES OF THE CRYSTALLINE LENS. turliaiu'c are iiK't with. Tlie cnjiulitioii interferes to .some extent, thougli ]ir()l>alily never completely, witli accommodation, and is often associated with myr>j(ia, the amount of wliicli is usually sliglit. AVhen a lamellar cataract is examined by oblique illumination (see Fig. 78), the first ajjpearance that strikes one is a tolerably uniform greyish opacity, which does not extend as far as the equator of the lens, and is more dense at its margins, from which often a few striae pass towards the capsule. On closer examina- tion tlie lamellar nature of the cataract can often l)e made out ; that is to say, it is not difficult, as a rule, to satisfy one's-self that tlie opacity is limited to one or more contiguous lamelhe, within, as well as external to which, the lens is transi)arent. The cause of the greater dark- ness of the margin is the relatively greater opacity which is caused by the anterior and posterior por- tions of the intransparent fibres meeting here. In this way, too, lamellar cataract differs greatly from other forms of cataract, which are usually darkest at the centre, where the opacity is deepest. It is seldom that the opaque layers, instead of being contiguous, enclose trans} )arent lamelke. The opacity occupies very different lamella) in different cases, and consequently the diameter of the opaque area differs ; there is never, however, an o^jacity of the layers immediately under the ca^jsule. In some cases short strite are to be seen, both in the anterior and posterior cortex. The cause of the intransparency ajjpears to be some arrest of development, at a time during intra-uterine life or early infancy, when the intransparent layers were the most superficial. There is little doubt that it is a rachitic change, and is sometimes associated with absence or defect of enamel on some of the teeth. Lamellar cataract usually, though by no means invariably, remains stationary. This variety of cataract is often overlooked until the patient attends school, and attention is drawn to it by Fig. 79. — Lamellar cataract ; oplitlialnio- scopic illuniination. LAMELLAR CATARACT. 201 the accompanying amblyopia or myopia. The amount of amblyopia is very variable in different cases. The oiierations performed for lamellar cataract are iridectomy, removal of the lens by discission, and extraction. Where there seems a likelihood of improving vision by displacing the pupil, which can be inferred when the vision, with proper optical correction if necessary, is improved by dilatation of the pupil, there may possibly be some justification for performing iridectomy, even when the amblyopia is comparatively slight. Removal of the lens, on the other hand, is attended not only with some risk ■ — certainly very slight — but also introduces more inconvenience by rendering all accommodation impossible, and should not be undertaken unless vision is less than one-third of the normal. The choice of operation is in some measure influenced by the conditions as to probable progression of the opacity. Where there is good reason to believe that a recent deterioration in vision has taken place, which is not due to increasing myopia, discission may be performed even although the visual acuity is greater than one-third of the normal. In most cases for which iridectomy is })erformed, it should be done upwards, as it might be necessary at some later period to extract the lens. In this situation, besides, it is less unsightly, and less liable to cause any disagreeable dazzling. Personally I have practically given up iridectomy for lamellar cataract. Congenital total cataract is usually soft, and involves all the layers of the lens. It is frequently also comjtlicated by a capsular opacity as well. These cataracts, too, undergo further changes in the course of time, and become shrivelled up and membranous, or in part calcareous. Degenerative changes, which take place in the suspensory ligament, often lead to their eventual dislocation. There is a variety of congenital cataract in which the opacity is mainly cortical, while a sclerosed nucleus occupies the centre of the lens. The best treatment for this form is to extract, just as in senile cataract. The more common form only requires discission, though, when calcareous patches exist, this has often to be followed very soon by evacuation of the swollen lens substance, as well as of the calcareous patches, through a small linear incision in the periphery of the cornea, owing to the irritation which the calcareous matter often pro- duces when it lies in the anterior chamber. In the shrunken membranous cases, with opacity of the capsule as well, the most satisfactory result is obtained by dragging the whole capsule out of the eye. This is apt to cause irritation unless done carefully. The membrane should be seized with a pair of capsule forceps. '202 DISEASES OF THI<: CRYSTALLINE LENS. and very gently and slowly, and, as it were, coaxingly, drawn out. If tlio resistance l)e very great, as much as will come without too great traction may be cut off with the iris scissors, and the rest left. Sometimes, instead of extracting, it is possible to get a good hole in the membrane with one or two cataract needles, or by cutting it across with a pair of de Wecker's scissors. The toughness of the structures generally, however, renders such ettbrts not very successful. Secondarij cnfanict most frequently begins with an opacity of the posterior portion of the lens, — what is called posterior polar cataract, — and is often very slow in advancing to other parts of the lens. The o})acity is the result of malnutrition, and is most commonly met with where there is disease of the vitreous, retina, or choroid. An opacity beginning at the posterior pole should always raise a suspicion of being secondary, and it will generally be found that the vision does not correspond to the oiJacity, and Fig. 80. — Sbowiug liistological appearance of capsular cataract in section. — After FucHS. that changes are to be seen with the ophthalmoscope in the deeper parts of the eye. An opacity of the postei'ior cai)sule rarely occurs, and is apparently mainly produced by deposition on it from the vitreous. Htationary imrtial cataracts, in which the opacities are sharply defined and punctiform or irregularly linear in shape, and in different })arts of the lens, are occasionally met with. They rarely i)roduce any great defect of vision. Capsular cataract may exist without any accompanying opacity of the lens. It is most commonly in the form of what is called pyramidal cataract, — a conical protrusion of a central portion of the anterior capsule, which is at the same time densely opaque. Sometimes pyramidal cataract is congenital, and then almost invariably bilateral. The pathology of this variety is not clear, but it seems to be the result of a retardation in the closure of TRAUMATIC CATARACT. 203 the capsule. As a rule, however, the capsular opacity is set up Avlieu the lens is for some time pressed up against the back of the cornea, after a ^perforation due to ulceration. Under these conditions, a proliferation and fatty and fibrinous degeneration takes place in the cells lining the capsule, and the homogeneous capsule itself is portruded in front of this. In consequence of this origin, there is almost always to be seen some scar in the cornea, indicating the position of the perforation. In many cases this is extremely faint, as the perforation has usually taken place in infancy, as the result of ophthalmia neonatorum, and the cicatricial tissue has gradually assumed an almost complete transparency. Often there is nystagmus in eyes with pyramidal cataract, and the vision is found to be more defective than can be accounted for by the limited opacity. The combination of pyra- midal catai'act Avith nystagmus is indeed almost a certain evid- ence of pre-existing oph- thalmia neonatorum, or vei'y early and extensive ulceration of the cornea. Traumatic cataract. — The transparency of the lens depends, under normal conditions of nutrition, on the in- tegrity of the capsule. As soon as there is a breach in its continuity, there is a great tendency for the lens fibres to become opaque. The most common cause, then, of traumatic cataract is a wound of the lens capsule. A severe blow on the eye, without any penetrating wound, is — less com- monly, however — followed by cataract, which must consequently be considered traumatic. In such cases it is doubtful whether the capsule is ruptured or not. Probably in all cases where a rapid opacity takes place it is ; indeed in some the rupture can be seen. In othei's, again, in which cataract slowly forms, the accompanying changes in the eye produced by the injury must be supposed to have in some way caused an interference with the nutrition of the lens. It is extremely rare that the capsule is injured without being perforated, as it is not often that the body which has perforated Fig. 81. -Stationary (piiiu'tifonu; cataract with numerous capsular deposits. 204 DISEASES OF THE CRYSTALLINE LENS. the external coat of the eye penetrates just sufficiently to scratch the capsule and no more. If the hole made in the capsule is very small, it may some- times heal without any opacity of the lens resulting. But even small ru]ttures, by admitting the aqueous humour into contact with the lens fibres, are apt to lead to cataract; an extensive rupture invariably does so, and some of the lens substance usually escapes into the anterior chamber, where it swells up, breaks down, and becomes absorbed. The results obtained by treatmeTit in the case of traumatic cataract are, on the whole, very much less favourable than for "^^^l^.^fcW^I^ Fig. 82. — Case of traumatic cataraLt, showing the oblique corneal scar marking the site of the perforating wound, also irregularity in the shape of the pupil caused hy synechife. any other form of cataract. This is mainly on account of the liability that there is for other parts of the eye to be involved in the injury, or to become subsequently inflamed. Much depends, too, upon whether or not septic matter is introduced into the eye Ijy the body with which it is wounded. The worst cases are those, of course, in which a foreign body is lodged in the eye. When the wound in the capsule is large, and a con- siderable proportion of the lens matter falls into the anterior chamber, a good deal of irritation is often set up, even when there is no septic element present. This is more likely to happen in adults, in whom the lens is harder and more irritating than in young individuals. TRAUMATIC CATARACT. 205 The treatment in all cases where the cataract has been caused by a perforating wound, should consist in bathing the eye frequently with a weak solution of corrosive sublimate, and in keeping the jiupil well dilated, if i>ossible, with atropine. Where there is much irritation, a careful examination should be made, in order, if possible, to determine the cause of it. If the rupture has been small, the lens is often found to be swollen in its capsule ; and, when this is the case, a larger opening should be made with a cataract needle, followed in a couple of days by removal through a linear incision of as much of the opaque lens as can be got away without any great difficulty. A more complete evacuation may be got by combining this with irriga- tion with warm neutral salt solution. Even if this should not Fig. 83.— Case of traumatic cataract iu which the swollen lens matter lies far forward in the anterior chamber. dislodge the remaining lens matter, it is a useful precaution in case any infection should have been introduced at the time of the accident. If the irritation is due to lens matter lying in the anterior chamber, a linear extraction may be performed at once. When it is evident that septic matter has been intro- duced, it is a good plan to combine the exti-action with a good- sized iridectomy, and to freely irrigate the anterior chamber with very weak chlorine water, afterwards using antiseptic dressings. An eye may sometimes be saved in this way, though at the risk of more or less permanent opacity of the cornea, owing to destruction of the epithelium lining its posterior surface. In some cases, however, in which the external wound is small and the reaction great and evidently due to infection, the following 20G DI.SKASKS OV TIIK ClIVSTALLINE LENS. treatment may l)e tried — Tlie wouikI is raiiterised freely with the therino-cautery ; freshly jtreparcd, fully saturated chlorine water is then injected sulx'onjunctivally, and some time allowed for the inHainniat(jry symptoms to subside before proceeding to the removal of the cataract. When complicated with prolapse of iris, the prolapsed 2)ortion should generally be excised, and as much as i)ossil)le of the opaque lens matter removed through the corneal wound. In cases Avhere the irritation is slight, and tends to subside under simple treatment, it is, as a rule, better to leave the catax'act alone until the eye has come completely to rest. Absorption often goes on Avithout any interference, or it may be hastened, when slow, by stirring up the lens once or twice with a cataract needle. A traumatic cataract, instead of becoming absorbed, may undergo different changes, which are for the most i)art similar to those already described as occurring in other over-ripe cataracts. Very rarely there is the formation of true bone in the lens. In such cases it is always present in the choroid as well. Ossi- fication never takes place unless the capsule has been ruptured, therefore only in traumatic cases. ] besides by absorption, there is another way in which trau- matic cataract may undergo a spontaneous cure. A gradual clearing up of the opacity may take place. This is only met with, and that very rarely, when the cai)sular wound has been small and rai)idly closed, while the opacity in the lens itself has been limited to the track of the liody with which the eye has been wounded. Traumatic cataract may be i>roduced liy wounds from almost every object which could possibly be imagined to be capable of l)enetrating the eye. An extremely common manner by which the lens is wounded is with a fork, which is often used by children to unfasten their shoe-laces. This accident is most frequently a severe one, as, apart from the double wound pro- duced by the two prongs, septic matter is generally carried into the eye. It is a common enough thing for the jjatients themselves, or those who come with them, to deny any accident. Wlien the presence of a cicatrix in the cornea renders it certain that there nmst have been one, and this is explained to them, they will then often admit it. A unilateral cataract in a young individual is, in fact, almost invariably traumatic, although some difficulty is ex{)crience(l sometimes in finding any trace of the situation in which the eye has been penetrated. OPERATIONS. 207 Glass-blowers' cataract. — Glass-blowers are subject to cataract, which more frequently seems to affect the left eye, or, at all events, to begin in the left eye. I have seen several cases of this form of cataract. There can be no doubt that the occupa- tion in some way favours the occurrence of opacity of the lens. Probably it is the action of powerful actinic rays. The curious preponderance of the cataract in the left eye is due evidently to the position in which the head is held in blowing. This position not only brings the left eye nearer the glowing glass, but brings the right eye under the protection of the nose. Cataract operations. — Discission or needling for cataract is practised in the case of lenticular opacities in young individuals. The object of the opera- tion is to allow the aqueous humour to come in contact with the lens substance, which is thus macerated and slowly absorbed. To effect this, it is necessary to make an opening in the lens capsule, and at the same time break down, to some extent, the substance of the lens as well. The instrument used for this purpose is a sharp needle, the body of which is made almost im[)erceptibly tapering, and at the same time accurately rounded, so as to prevent any escape of aqueous whilst it is in use. Before operating, the pupil should be well dilated with atropine. Having taken a good hold of the conjunctiva close up to the cornea, with the fixation forceps held in the left hand, the needle, which has been rendered thoroughly aseptic, is pushed through a peri- pheral portion of the cornea until it reaches the capsule of the lens. The handle is then slightly depressed, and at the same time the needle pushed a little farther through the cornea, and then, by a movement round the portion of it which is grasped by the cornea as axis, it is made to make a cut through the capsule in a vertical or nearly vertical direction. It is then slightly withdrawn, and a horizontal incision made through the cajisule in the same way. The capsule is thus opened by a crucial incision, and after this has been done, more or less of the lens may be stirred up with the end of the needle, care being taken that the whole thickness is not pierced at any place. The needle is then withdrawn, the eye washed with a stream of warm sterilised water, and a bandage applied. For some time afterwards the 2)upil nuist be Fig. 84.— Cataract stop-needle. 208 DISEASES OF THE CRYSTALLINE LENS. kept well dilated with atropine, so as to prevent any synechiae forming. The main jioint in the operation consists in making a satis- factory opening in the ca})sule. If the needle be merely stuck into the lens, and the point then moved about so as to stir it up, a proper absorption does not follow, and there is a risk besides of rapid swelling taking place within the capsule, which may give rise to considerable irritation. In children no further operation is absolutely necessary, as a rule. Every case should, however, be carefully watched for some days afterwards, as it occasionally happens that when a considerable quantity of macerated and swollen opaque lens matter falls all at once into the anterior chamber, it intei'feres with the normal excretion of the licpiids of the eye, and may thus give rise to glaucomatous symptoms. When this occurs, there is often at the same time pain and vomiting. It is the more likely to occur the older the individual on whom the operation is performed, and the more freely the lens has been needled. Under these circumstances it is necessary to extract as much of the lens matter as can be readily got away from the anterior chamber. There are different ways of doing this, but the best is by making a small linear extraction. This is done with a keratome (see Fig. 157). The keratome is entered through the apparent corneo-scleral margin, taking care that the wound is perpendicular to the surface. The incision thus made should be 4 or 5 millimetres in length. After withdrawing the keratome, the upper lip of the wound is depressed with a small scoop, along which the aqueous and lens matter are allowed to escape. If the whole of the contents of the anterior chamber do not come at once in this way, the eye may be closed for a minute or two, and the manoeuvre repeated. It is best, if possible, to avoid introducing the scoop frequently into the chamber, and in any case it is not necessary, although of course it hastens matters, to extract all the lens substance. Many surgeons make a practice of always extracting a few days after needling, whether that be followed by any irritation or not. The time required for the cure of the cataract is thus Fig. 8. Cataract scoop. OPERATIONS. 209 shortened, and, if a linear extraction performed in the way described be practised, with proper aseptic precautions, it is a very safe proceeding. There is necessarily, however, a slight increase in the risk as compared with needling alone and leaving the absorption to take place in the course of nature. The broken-up lens matter may also be removed by the method of suction. Having made a linear incision in the cornea in the manner already de- scribed, the nozzle of a suction syringe is introduced well into the anterior chamber, and the softened lens matter slowly sucked up into it. Two forms of syringe are used. Bowman's and Teale's. In the one the suc- tion is got by means of raising a piston with the thumb, while the tube of the syringe is firmly held by the first and second finger inserted into two rings fixed to the tube. The other suction curette consists of a silver nozzle attached to a glass tube 4 or 5 in. long, ending in a flexible indiarubber tube, with a glass mouthpiece at the other end. The suc- tion is made with the mouth. Those who attempt removing lens matter by suction should pay attention — first, to securing the absolute asepticity Fig. 86. — a, Spring speculum ; h, fixation forceps. of the syringe ; and, secondly, to the manner in which they hold it in the chamber. An instrument of this kind, it must be remembered, is more difticult to render aseptic than most others. The nozzle has its opening on its anterior surface, consequently it is necessary, 14 FULL SIZE 210 DISEASES OF THE CRYSTALLINE LENS. in order to avoid having to exert too powerful a .suction, to get it well behind the matter which it is desired to suck up. Care nuist also be taken that it does not get ])ehind the iris, or be allowed to enter so deeply that the jiosterior lens capsule is rujttured. Very pretty results may be obtained by this method ; but it is very questionable whether on the whole it is better than the simple linear extraction, and it is certainly not so safe. ^ULL SIZE SULLSIZE Fig. 87.— c, Grat-fe's kuife ; b, tor- Fig. 88. — a, Iris Look inaile of jjlat- toise-.sliell scoop ; c, t-ystotome. inuni, which cau be bent into any shape and sterilised in tlanie of siiirit himp ; b, iris forceps. Cataract extraction. — The method of extracting senile cataract, now almost universally followed, is one which difters but to a slight extent from that introduced by von Graefe as his modified linear operation. The instruments required for extraction with iridectomy are the following (see Figs. 86 to 89) : — A spring speculum, a fixation forceps, a narrow cataract knife (Graefe's knife), a pair of iris forceps or iris hook, iris scissors, a cystotome or capsule forceps, and a tortoise-shell scoop, generally fixed at the other OPERATIONS. 211 end of the cystotome, as in Fig. 87. Further, in case they should be required, there sliould be at liand a caoutchouc or tortoise-shell spud for replacing the iris, and a wire vectis to remove the lens, should it become dislocated, or should there be any early escape of vitreous. It is useful to have also a wire elevator (Fig. 90), which can be used when the speculum has been FULL size Fig. 89. — Iris scissors. 212 DISEASES OF THE CRYSTALLINE LENS. removed, if it should l)e necessary, or appear advisable to remove that instrument before the completion of the operation. After the eye has been cocainised, and the conjunctival sac well washed out with corrosive sublimate solution, 1 to 5000, the speculum is introduced. The form of speculum shown in Fig. 86 is a useful one, as it can be used for either eye without getting in the way, and is sufficiently strong, owing to the rectangular shape of the arms, to resist any attempt on the part of the patient to close the eye. If the operator uses his right liand for making the section, he will stand behind the patient when operating on the right eye, and in front of him when V( Fig. 90. — «, Wire vectis ; /;, tortoise-shell spud ; wire elevator. operating on the left. This is necessary, as, owing to the nose getting in the way, the section has to be made from the temporal side. A firm hold is taken of the conjunctiva and subconjunctival tissue, close up to the cornea, with the forceps held in the left hand. This fixation should generally be made iu a line with the. vertical diameter through the cornea, and therefore exactly OPERATIONS. 213 opiX)site the mid-point of the section about to be made. If fixation be made at any other place, it may interfere with the proper performance of the section. The knife is then entered by making a j^tincture at the corneo-scleral margin, and at a point on a level with a semi-dilated pupil. In making the puncture, the point of the knife is directed towards the centre of the pupil, or rather lower. As soon as it has properly entered the chamber, it is steadily pushed forwards, while being gradually given a direction parallel, or nearly so, with the horizontal diameter through the cornea, until its point catches in the angle of the Fig. 91. — Showing method of performing sectiou for cataract extraction. anterior chamber exactly on a level with the first puncture. At this ix)int the counter punctiire is made, and then the knife is quickly, and with as little sawing as possible, cut out, so as to make a section which lies throughout just about in the apparent corneo- scleral margin (Fig. 91). If the knife should catch too soon, that is, before its point has reached fairly to the angle of the chamber, it may be slightly withdrawn and directed towards a better point. This must be done carefully, and without increasing the size of the opening at the puncture, so as to retain the aqueous humour as far as j)ossible. Sometimes, owing to the a(jueous escaping, the iris falls in front of the knife immediately after the counter }>uncture has been made. When this happens, two courses are oi)en to the 2U DISEASES OF THE CRYSTALLINE LENS. operator, — either to withdraw the knife slowly, and iio.sti)one the oiH3ratioii for some days, or proceed witli the section, cutting through the iris at the same time. The latter does not interfere altogether with the successful termination of the operation, although it may complicate it by causing bleeding into the anterior chamber. After the section has been made, if there be any little flap of conjunctiva, it should be turned over on to the cornea, so as to free the lips of the wound. A piece of iris is then removed with the iris forceps or iris hook and scissors. Personally, I always use the hook, which, being made of platinum, can be sterilised by holding it in the flame of a spirit lamp, and which can be i-eadily bent into any shape best suited for easy intro- duction. The use of the hook has the advantage, too, of causing no i>ain, as with it the margin of the pupil, not the surface of the iris, is seized. A small iridectomy, 4 to 5 millimetres in w'idth, is all that is required ; it is therefore not necessary to exert any great traction with the forceps or hook, care being taken only that the pupillary margin is draAvn out. The cutting should therefore also be made with one snip, and not, as was at one time very much practised, by means of several snips, freeing first the one side, and dragging out as much iris as could be got. By cutting the iris in this manner, and by making the incision in the way described, and not more peripherally, as was formerly done, we may to a great extent avoid any encleisis of the iris. After the iridectomy has been completed, it is well to see that the iris is free. If not, a little friction made Avitli the lid over the eye will generally be sufficient to free it ; but, should this not be the case, recourse may be had to the caoutchouc spud, which can be used to much greater effect at this stage of the operation than after the lens has been removed. If there is now any manifest pressure of the speculum on the eye, or if the patient is unruly, that instrument should be removed, or an assistant may be allowed to hold it in such a way as to avoid any pressure. The cystotome is then introduced into the anterior chamber, the cutting edge or pricking point being held parallel with the surface of the lens, until it has been pushed as far down as the lower margin of the pupil, or, if it can be done without any difficulty, even behind the iris in this situation. The point is then directed to the lens, the capsule of which it readily pierces, and in which it is made to tear an opening by being steadily withdrawn in a vertical direction towards the external incision. A similar rent is then made in the capsule at right angles to this one, and as nearly as may be along its upper circumference. lu OPERATIONS. 215 this way an irregular "P-shaped opening in the capsule is obtained. The object of opening the capsule is to permit of the easy escape of the lens. It is a point which has always been much discussed, which is the best way of doing this 1 I am not pre- pared to say that the way just described is better than any other that may be employed ; but what is pretty certain is, that the more free the opening can be made the more easily and com- pletely can the opaque lens be removed. Care should therefore be taken that the cystotome really cuts the capsule, and is not allowed to pass in between it and the lens after having made a rent in it. It is to avoid the possibility of this that it is well to pass it far down first, and' then to cut towards the periphery. A good opening can be got by using a pair of capsule forceps instead of a cystotome. The forceps are passed in closed, until the points are slightly beyond the centre of the lens, when they are opened, pressed gently against the surface of the capsule, and closed. They are then withdrawn slowly and by a slight side-to- side movement. In order to see whether they have removed a satisfactory portion of the capsule, they may be transferred at once to the dish containing the antiseptic lotion, and the portion of cajjsule allowed to float off. The capsule forceps are some- what more difficult to manipulate than the cystotome. Care must be taken not to press too firmly on the lens, as it may readily in this way be dislocated. They must also be held in such a way as to avoid their catching, farther back from the points, in any of the tissues in the external incision, which would much interfere with its tearing away a portion of the capsule. Where a cataract is complicated with an opacity in the capsule, the forceps are far more satisfactory than the cystotome, as by using them the oi)acity is removed at the same time that the capsule is |)roperly opened. This proceeding is generally safer than removing the capsular cataract after the lens has been extracted. The next step in the operation is to effect the removal of the lens. For this purpose external pressure has to be made. The back of the tortoise-shell scoop is applied to the lower part of the cornea, and pretty firm i)ressure exerted. This causes the wound to gape, and the up} )er circumference of the lens to become engaged in it (see Fig. 92). When the lens has projierly pre- sented in this way, the pressure is increased, and at the same time the scoop gradually caused to follow it upwards as it becomes more and more disengaged, until it is finally completely expelled. After this has been accomplished, it is Avell to wash out the con- 216 DISEASES OF THE CKVSTALLINE LENS. jiinctival sac again with the antiseptic lotion, and then, by pressing and rubbing u}) tlie lower lid against the cornea with the thumb, any cortical matter which has been rul)bed ott" and remains in the eye is to be, as far as possible, g(jt rid of. During this coaxing out of the cortical matter, care should be taken to keep the eye well washed with the corrosive sublimate lotion, as it is otherwise not free from danger, owing to the possil)ility of micro-organisms being carried into the wound from the lid. It is better, however, except where there is dacryocystitis or chronic conjunctivitis, to make the necessary pressure on the cornea through the lid, and not directly, as it can be done with less irritation or injury to the cornea. An idea of the completeness of 'the removal of the cortex J'lo. 92. — Leus escaping through incision. may be got Ijefore applying the dressing, by seeing whether the patient can count fingers or not. If this can readily be done, it shows that the pupil is clear. If the operation has been j^er- formed for an unripe cataract, there may be some clear cortex remaining, Imt all opacpxe matter at all events has been removed from the line of vision. When this clearing has been made to a sufficient extent, or as far as may be advisable in any parti- cular case, the caoutchouc s})ud should be run along the wound, in case any jtiece of capsule or cortex should be caught in it. If there should be any clotted blood, too, it must be removed with the iris forcei)s, and attention must be paid to the I'upil, and any catching at the angles of the wound rectified in the manner already described. A dressing must be then applied. OPERATIONS. 217 Different dressings are used by different surgeons. The following may be recommended : — Next the eye, which is gently closed, is placed a piece of lint soaked in the coiTOsive sub- limate solution. A pad of absorbent cotton-wool is then put on the top of this deep dressing, and kept in position by a couple of strips of adhesive plaster. Over this is placed a light shield of aluminium, by which the eye is protected from any slight knock which the patient might inadvertently give it. This dressing is not changed for twenty-four hours, and after the eye has been examined, and if necessary bathed with a little warm sterilised water, is reapplied as before. The same dressing is continued, and changed every twenty-four hours, for four or live days, after which all that is required is a pair of dark glasses during the day, and the aluminium shield at night. If, as is generally the case, the chamber has re-formed within the first twenty-four 93. — Wire netting shield. hours, the antiseptic lotion should be discontinued on the third day at latest, and a little soft boracic or iodoform ointment applied to the margin of the lids to prevent the retention of the secretions. It is not necessary to tie up the other eye, as the patient himself does not move either eye much, owing to the pain which this causes, until the anterior chamber has re-formed. The wound has generally so far healed by the time the first dressing is changed, as to have permitted the chamber to be- come re-established. If there should be no chamber after two days, — an unusual though occasional occurrence, — it is better to remove the dressing altogether and use the shield alone, or a double wire-netting shield, as shown in Fig. 93. The patient should be kept in bed for a couple of days at anyrate, unless he should be very corpulent, or should suffer from diabetes, when it is generally inadvisable to kee|) him in bed after the 218 DISEASES OF THE CRYSTALLINE LENS. first (lay. For tlie first few days it is as well to keep the patient in semi-darkness, where this is possible ; lie should at anyrate he protected from any strong light falling directly on the eyes. If during the attempt to force the lens through the external wound any of the vitreous should escape, it becomes necessary to abandon the pressure on the cornea, as this would only cause further loss of vitreous without resulting in the escape of the lens. The lens has then to be extracted with the vectis (see Fig. 90). This instrument is pushed well behind it, by first being passed backwards, taking care not to dislocate it any farther. When it has been got well in ]>ositioii behind the lens, it is Avithdrawn slowly, a slight pressure forwards being exerted all the time, so as to j)reveiit the lens from slipi)ing off by supporting it against the cornea in front. It is generally necessai'y to leave most of the cortical matter which may not have been extracted with the vectis. Some of it may be re- moved by carefully introducing the curette, but this proceeding should not be repeated too often ; and if there has been a good deal of vitreous expelled at the same time as the lens, should not be tried at all. When there has been an escape of vitreous, extra care must be taken when examining the eye afterwards. Syringing out of the anterior chamber has been recommended in cases where it is difficult to remove cortical matter, as where the cataract has been immature at the time of operation. This is used instead of the external pressure exerted either directly on the cornea or through the lid, as has just been described. It is seldom, however, that when the capsule has been properly opened, and some time given for a little aqueous humour to accumulate, any such proceeding is called for. When an extraction has been performed in an eye where there has been any dacryocystitis or conjunctivitis, it is a good plan to cover up the wound with a thick layer of finely powdered iodoform. Such eyes are better left without a bandage, although it is safer to use the ])rotecting shield. In a very considerable proportion of cases of extraction some degree of iritis takes place during the healing process. As a rule this is very slight, but wherever there is any indication of it, atropine should be used to prevent much adhesion to the lens capsule. The most unfortunate accident which may happen after an extraction is suppuration of the corneal wound. If this goes on, it leads to more or less complete destruction of the cornea by extension of the inflammatory changes, and this, as well as a complication with purulent iritis, to which there is a tendency, OPERATIONS. 219 results in the loss of all useful vision, and not infrequently in the complete disorganisation of the eye. This accident is prob- ably always due to septic inoculation of the wound. It generally begins, so far as it can be observed, after the first twenty-four hours. The chamber is then found to be empty, the conjunctiva reddened and chemotic, the edges of the wound are slightly infiltrated, and a greyish haze extends more or less distinctly down into the cornea. The patient complains of pain, and has often suffered during the night from sickness. When this state of matters is observed, no time should be lost in attempting to check the pro- gress of the infiltration. This may be done either by using the thermo-cautery, or by apply- ing a solution of nitrate of silver, 10 grs. to the ounce, directly to the wound. The eye should afterwards be frequently bathed with the cor- rosive sublimate solution, or, better still, with freshly prepared chlorine water. In some cases of cataract it is advisable, instead of rupturing the capsule of the lens, to extract it as well along with the lens. Some operators even make this a rule. The result, as far as vision goes, is more immediately brilliant than when the capsule is left in the eye, Init the operation is certainly much more risky, as it entails the loss of more or less vitreous, besides the irritation which may result from the tearing away of the suspensory ligament from its attachments. In all cases, however, where the lens is more or less dislocated, or where it is over-ripe and shrunken, and also where it has undergone calcareous degeneration, it should be extracted in its capsule. Pagenstecher's curette or spoon (Fig. 94) should be used for this purpose. It is introduced well behind the lens, which by it is pushed up against the back of the cornea ; a tortoise-shell scoop is then used, with which pressure is exerted on the cornea, so as to cause the lens to glide slightly upwards on the large spoon. When it is found to move, the spoon is slowly withdrawn, whilst at the same time external pressure is kept up with the scoop, which is made to follow the other instrument as it is removed. This operation requires the aid of a skilled assistant to manipulate the external scoop, while the operator holds the fixation forceps in one hand and Pagenstecher's spoon in the A FOIL SIZE Fig. 94. — Pagen- stecher's spoon. 220 DISEASES OF THE CRYSTALLINE LENS. other. AVhen oarofullv jti'iforniod, there need not be any great loss of vitreoun ; l»iit that will depend to .some extent on the consistency of the vitreous. In cases of capsular cataract, and of shrivelled-up congenital cataract in children, the wliole tliickened ojjaque membrane may be removed with the capsule forcep.s through a fair-sized linear incision in the manner and with the precautions already described. If, owing to having made too small an incision, or to any other cause, considerable difficulty has been experienced in extracting a cataract, so that the scoo}* has had to be used more freely on the cornea than usual, there will be found on examin- ing the eye next day a milky striated opacity of the cornea. This appearance, though it may last for a varying length of time, eventually clears off. It is due to injury to the cells lining the back of the cornea, and is favoured by the action of cor- rosive sublimate when some of the lotion used during the operation passes into the chamber. In some cases the appearance seems to be produced by folds in Descemet's membrane. In such cases it rapidly disai)pears. An opacity clue to cocaine has been described, but this I have never seen, though I have all along used it freely, and in combination with corrosive sublimate and different other anti.septics, as well as with mydriatics and miotics. There can be little doubt that this is due to the presence, in some specimens of cocaine, of an ii'ritant alkaloid which cannot i-eadily be separated from the cocaine. The opacity i)roduced ap})ears to be contined to the epithelial layer of the cornea, though it may never- theless remain |)ermanent. Cataract extraction without iridectomy. — This is the so-called simple exti'action, as oppo.sed to comhined extraction. Many surgeons appear to have almost conqjletely abandoned the com- bined operation in favour of .simple extraction. Others select the cases for which, in their opinion, the one operation is more suitable than the other. Which method is the one pre- ponderatingly resorted to differs, of course, according to the circumstances which are allowed to influence the selection. The main claims which have been made in favour of simple Fig. 95.— Cap- .sule forceps. OPERATIONS. 221 extraction are that the cosmetic effect is superior, and that mutilation of the iris is avoided. The introduction of cocaine anaesthesia, and the rigid adoption of aseptic precautions, have made it possible to give effect to such considerations, which at one time would rightly have carried no weight. The great bugbear of simple extraction, on the other hand, is the possi- bility of subsequent iris prolapse. As regards the visual acuity which may be got by each method, probably few who have a large experience -of both can confidently assert that there is any material difference. This, at all events, has been my experience. It is not difficult to understand that those who were in the habit of making very lai-ge iridectomies, such as were the rule for some time after the introduction of the modified linear extraction, should have resorted to the simple operation and discarded iridectomy altogether. These large iridectomies are certainly unsightly, and the proportion of cases in which encleisis takes place, when the section is made as peripheral as von Graefe recommended, is by no means trifling. Besides, the large peripheral portion of the cornea, through which rays are thus permitted to reach the retina, is apt to render the image less sharp. On the other hand, the same disadvantages do not attend the performance of a small iridectomy and a less peri- pheral incision. There is little tendency to bad encleisis and little interference with vision, esjjecially when the iridectomy is done upwards. The removal of the cataract is also easier if unripe, and the risks on subsequent bursting of the wound are less. Are, then, the only disadvantages a fresh wound in the iris and a less beautiful pupil 1 Those who have been in the habit of operating in this manner may fairly claim that the former disadvantage, which may even be got rid of altogether by the performance of a preliminary iridectomy, is at least out- weighed by the diminished risk of encleisis or bad prolapse of iris in case of the wound bursting where no iridectomy has been done. The cosmetic advantages of a round active pupil, too, when it can be obtained, are altogether trifling in those elderly individuals who are the usual subjects of cataract extraction. It_has to be borne in mind that whereas the combined operation is suitable for all cases of cataract, this is not so with the simple operation. Even those who make it a rule not to "mutilate" the iris, are in a certain proportion of cases obliged to do so. There are, however, other and more important advantages in a simple extraction than the mere retention of a round pupil, if 222 DISEASES OF THE CRYSTALLINE LENS. tlie oi»erati<)n is peifuniifd liy the method to be presently described. On the other hand, there are unquestionably greater difficulties in the siniitle operation itself. There are, in addition, cases in which it is more or less unsuitable. A proper course, therefore, — that is, one calculated to give the best results in a large number of cases, — necessitates making a selection. If it were necessary to choose between the two operations one which should be put in practice in every case, I should unhesitatingly choose the operation with iridectomy. That operation, too, I should re- commend to all whose experience of extracting for cataract is limited. Hence in talking of making a selection, I mean select- ing the cases in which one may attempt to get the greater advantages of the simi)le operation with the best chances of success. The best method of performing simple extraction is one which, so far as I know, is due to Professor Snellen of Utrecht. The incision is large, occupying half the circumference of the cornea. It lies in the apparent corneo-scleral margin, and is made with a large and broad conjunctival flap, the knife being carried for fully a quarter of an inch below the conjunctiva before cutting out, after the section at the corneo-scleral margin is completed. The cystotome is introduced from the side ; that is, at the one end of the incision. The cornea is then pressed upon below the centre, so as to cause the large wound to gai)e considerably, and make the edge of the lens escape in front of the iris. A strong solution of pilocarpine is used immediately before operating. Needling is done a fortnight later. The large incision which has to be made, in order to remove the lens easily and without injury to the iris, is perhaps to some extent a disadvantage. Other things being equal, the smaller the incision through which the lens is extracted the better. The site, howevei', at the corneo-scleral margin secures good apposi- tion, and the large conjunctival flap provides well for the vitality of the cornea and for rapidity of healing. The incision, though large, has not, therefore, any of the objections which led to the abandonment of the old corneal flap of the earlier simple extractions. The only serious disadvantage, then, is the difficulty of making it satisfactorily, so as to avoid getting the iris in front of the knife, and so as to secure a good conjunctival Hap. This requires some practice. The knife has to be very slightly tilted, with its edge directed more backwards, so that part of its flat surface may be used to support and, as it were, press forward OPERATIONS. 223 and raise the cornea while the incision is being made. One is more dependent, too, u})on the patient keeping the eyes quiet and not making any violent or sudden attempts at rotating them upwards. Hence the reason for cocainising well and for providing a ready ol)ject for fixation, preferably a candle flame, which can be employed even when the other eye is totally blind. If the iris does fall in front of the knife, and is cut as the incision is com- pleted, one cannot well make the large conjunctival flap ; and one is of course, in consequence, rather Avorse off than if one had made a smaller section and an iridectomy in the ordinary way. But this should not often happen. The large conjunctival flap leads to a more rapid re-forming of the anterior chamber, which is generally comjdete in an hour or less. This cannot but be an advantage in overcoming the risks of inoculation by micro-organisms, much as rapid operating, with as little interference as possible with the wound after it is made, is to be preferred in this respect to slow deliberate cutting. It is not improbable, too, that the large, cut, lymph-exuding con- junctival surface has a valuable effect in acting as a trap, and in destroying germs which might otherwise have to be fought in the corneal wound or cliamber. To come to the c[uestion of iris prolapse. Prolapses do occur, but they occur only during, and sometimes within an hour or two after, operation, but very rarely later. Since becoming alive to this, I have made it a rule to perform iridectomy whenever the iris does not at once go back of itself or by rubbing on the cornea, or after running the shell repositor along the wound, and go back so completely as to leave a perfectly round and con- tracted pupil. No doubt iridectomy at this stage will be necessary more often at the hands of one operator than of another. I have to resort to it in about one case out of ten, and I believe it is more prudent to overdo this precaution than otherwise. The eye should, in fact, always be examined in about an hour after opera- tion. This is especially desirable where the patient has been allowed to walk from the operation table to bed. It is compara- tively rare to find a prolapse then if a strong solution of pilo- carpine has been used ; but if found, it should be removed, and not replaced. With these exceptions, prolapse practically does not occur. Even the risk of a slight blow to the eye, which is not so un- common an occurrence, and which often leads to a bursting of the wound and obliteration of the chamber in the ordinary operation with iridectomy, need not be feared. The wound, 224 DISEASES OF THE CRYSTALLINE LENS. owing to the rai)itlity of healing of tlie conjunctival flap, is so much stronger that, should it give way at all, it does so over a comparatively small extent. It may be said. If it is necessary, in order to prevent prolai>se, to do iridectf)my in such a consideiable iirojjortion of cases, this is surely an objection to the simple operation. And no doubt it is ; it is the oVyection, far before the tendency to after- prolapse, which is practically nil, and much greater than that of the technical difficulty in performing the operation, w'hich can be overcome. In my exjjerience, iritis occurs less frequently after simple than after combined extraction. Whether this is due to the absence of any wound in the iris, to the absence of any incar- ceration of portions of the lens capsule, or to the introduction of fewer micro-organisms into the anterior chamber, or to any or all of these imaginable causes, I am not })re}iared to say. Complete freedom of the iris from any encleisis or any adhesion to the wound is much more frequent in the simple extraction by Snellen's method than when iridectomy is i>er- formed. In the combined operation one often finds some more or less marked difference in the \\ai\q of the two limbs of the coloboma, indicating adhesion. It is this which to my mind establishes the value of a suc- cessful simple extraction, and makes it worth striving to attain, notwithstanding the disadvantages above referred to. This complete freedom of the iris can often be got, and its value is of a very different order than the purely cosmetic round pujnl or the avoidance of what is sentimentally called mutilation of the iris. If, further, one takes into consideration the rapidity of healing, the comparative freedom from iritis, and, if you will, the round pupil, one must be tempted to select cases in which there are good grounds for hoping that these advantages may be realised. Cases of hard, nuclear, black cataract in very old people ; cases of over-ripe cataract, with capsular opacities and disease of the suspensory ligament ; cases where there is a very shallow anterior chamber ; cases in which there is a foreign body in the lens ; and cases complicated by iritic adhesions ; also where one has to do with a very nervous, unruly patient — may be more suitably treated by the combined operation, with not too large an iri- dectomy. Operations for after-cataract. — In a certain proportion of cases in which a cataractous lens has been removed, it becomes necessary, sooner or later, to perform some operation in order to further increase the transparency of the pupil. The proportion DISCISSION. 225 of cases where this is necessary is less the more completely the cortical lens matter has been removed or afterwards absorbed. The degree of iritis, too, following the extraction is of influence in this resjject. When there has been any considerable degree, a subsequent operation will always be necessary before good vision can be obtained. On the whole, a second operation is most frequently required where the first operation has been per- formed before the cataract has l)een quite ripe. The operation to be selected in any case de^jends upon the degree of opacity as well as upon the nature of the membrane. The single cutting needle operation. — The operator 1 steadies the eye with the fixation forceps, and intro- H duces the needle through the outer or inner side of the cornea, according as the right or left eye is the one operated on. The needle is pushed obliquely inwards until its point penetrates the membrane as far over to the opposite side as is possible without wounding the iris. It is then swept round in this position, so as to cut a good opening in the membrane without penetrating deeply into the vitreous. By first piercing it, the membrane comes to lie with its cut edge up against the cutting edge of the needle, and is easily divided without any trac- tion. This operation is suitable in all cases whei'e an operation is required, shortly after extraction, to complete the transparency of the puijil, and where there has not been so much iritis as to lead to any drawing up of the pupil. A double needle operation is often used for such cases as well ; but when the membrane is tough, it is more difticult to pi'ocure in this way a satisfactory opening, a longer manipulation is necessary, and, besides this, there is liable to be a degree of dragging on the attach- ments of the membrane, which may lead to very considerable irritation, and the eventual closing up of the aperture. Person- ally, I use the single sharp needle in all cases in which irid- otomy is not necessary. In needling after a simple extraction, a detachment of any synechiie that may have formed can be made at the same time, and thus a round mobile pupil be got. When the operator has assistance, the cutting operation may be performed by oblique illumination, with the patient seated on a chair in the dark room. The scissors ojieration, or iridotoiny. — A good hold is taken of 15 Fou. Size Fig. 96.— Small knife useilfordis- cissioii. 226 DISEASES OF THE CRYSTALLINE LENS. the conjunctiva with the fixation forceps, and a narrow keratomc introduced into the anterior chamber as near as possible to the corneo- scleral margin. The keratomc may be made to pierce the iris at the same time. The incision should not be t(jo small, as it should l)e large enough to enable one to use the iridotomy scissors freely ; it should therefore be at least 4 mm. at its inner opening. After the keratome has been slowly withdrawn, a pair of Wecker's iridotomy scissors are introduced. The one blade, which should be sharp-pointed, is passed well underneath the iris and membrane, and the other above them until the opposite angle Fig. 97. — Showing the clear pupil got after a needling operation. The remains of the retracted capsule are seen below. of the chamber is reached, when, by a firm snip, the intervening tissues are divided, and the scissors (juickly withdrawn closed. The direction in which the blades of the scissors are passed should be at right angles to the stretched fibres of the iris. This operation is suitable for most cases where the pupil has become closed and drawn up owing to iritis after extraction. The iridotomy scissors are often made too long in the blades. They should not be much larger than two-thirds the diameter of the anterior chamber, or three-eighths of an inch. The difficulty in performing the operation properly is to get the blades sufficiently separated so as to pierce through the Avhole thickness of the obstructing screen near enough to the side at FULL SIZf Fk;. 98.— Irid- otomy scissors, with sharp- and liliint - pointed blades. IRIDOTOMY. 227 which the section is made. It is on this account that it is advisable not to make the section too small, and at the same time to pierce the iris and subjacent membrane with the keratome. Excision of a triangular 2nece of iris. — In cases where the iritis following extraction has been very severe, and where there is consequently a want of elasticity in the opaque screen, owing partly to wasting of the muscular tissue of the iris and partly to the tough nature of the plastic tissue to which it is firmly glued, the following proceeding may sometimes give a fair result : — A small flap, consisting of both cornea and iris, is made about midway between the centre and lower circumference of the cornea, but rather nearer the latter. Two converging snips Fig. 99. — From a case in which iridotomy was performed. upwards are then made with the scissors from either end of the iris flap, and thus a triangular piece of iris and subjacent membrane isolated, which is then seized and removed with the iris or capsule forceps. In these cases the vitreous is often much liquefied, and a considerable amount necessarily escapes during the operation, the permanent effect of which depends upon the degree of reaction following, as well as upon the clear- ness of the vitreous. An absence of complete consolidation in some portion of the scar, corresponding to the line of incision for extraction of cataract, sometimes occurs, and results in a more or less pro- nounced cystoid swelling. This is a condition which should never be left untreated. Apart from the irritation and discomfort which it may cause, and from the greater than usual degree of 228 DISEASES OF THE CRYSTALLINE LENS. astigmatism with wliicli it is occasionally associated, there arc risks attaching to this cicatricial defect which call for interfer- ence. The cystoid cicatrix is liable to injury, and, when injured, may furnish a nidus for micro-organisms, and an entrance for them into the deeper parts of the eye, which may lead to serious destructive inflammation. Often the condition does not develop until some time after the patient has been discharged. When the little cyst is opened into, it comparatively rarely happens that the aqueous humour is evacuated. There must therefore seldom be a direct com- munication between the cyst and the anterior chamber, although, no doubt, the scar tissue admits of filtration. Usually, if the Fig. 100. — Cy.stoid cicatrix. cyst has existed for some time, it is much larger than the real defect, as it is only a small portion of the underlying scar that is filtrating. Often the defective portion can be readily seen through the transparent cyst wall. It is nearly always apparent after the conjunctiva has been cut through. It is this part only that has to be attacked. The best means of doing so is with the thermo-cautery. The conjunctival wall of the cyst should first be slit up from end to end with a Graefe's knife. In doing so, the edge of the knife may be ke^jt directed away from the cornea, so that the collapsed Avail of the cyst may form a con- junctival flap. The Hap, when sufficiently large, is turned down over the cornea, and the underlying tissues cleaned by a stream of sterilised water or weak sublimate lotion. Whether or not DISLOCATION. 229 there is then any oozing away of aqueous humour, the visil^ly weak portion of the scar is next touched with the fine point of a thermo-cautery, and the flap replaced without being stitched. The burning should not be deeper than to penetrate through, at most, one-half the thickness of the scar. It should have its greatest length in a line with, and not perpendicular to, the scar. A dressing may be ajiplied for twenty-four or forty- eight hours afterwards. Occasionally this little operation may have to be repeated before the desired smooth cicatrisation is obtained. Dislocation of the lens. — In order that the lens may be displaced, some rupture or destruction or weakening must take place in some part of the zonule of Zinn. Dislocation occurs traumatically and idiopathically ; in the latter case also con- genital ly. Dislocation, whether traumatic or idiopathic, may be complete or partial. A partial dislocation or subluxation of the lens exists when some portion is tilted out of position whilst the centre remains in its place. The tilting may be in any direction. The partially dislocated lens often remains clear, and the diagnosis may con- sequently be difficult if the degree of displacement is slight. Astigmatism following a blow on the eye may be due to a slight displacement of the lens of this nature. When the subluxation is at all marked, a pushing forwards of the iris at one portion, and a consequent shallowing of the corresponding portion of the anterior chamber, is observed, with a tremulousness of the iris in the opposite dii'ection. There is then no difficulty in the diagnosis, especially when the pui:)il is well dilated, and the edge of the lens, often slightly serrated, is to be seen with the ophthalmoscope. Complete dislocation takes place into the vitreous, or forwards into the anterior chamJ/er, or, in case of rupture of the sclera, subconjunctivally. The first is the most common. The dis- location may be so complete that the lens is entirely removed from the line of sight, and lies at the bottom of the vitreous chamber, where it may remain for long transparent, though as a rule it very rapidly becomes intransparent. When the vitreous is liquid, the dislocated lens bobs up and down with the move- ments of the eye. More commonly the dislocation is not so complete, and then the edge of the lens can be seen with the ophthalmosco])e. A traumatic dislocation is very frequently associated with a separation of the peripheral attachment of a portion of the iris (irido-dialysis), or an inversion of the iris, either complete or partial. Often in the case of idiopathic dis- 230 DISEASES OF THE CRYSTALLINE LENS. location tlic lens has been previously iutransparent, and vision may even be imi»roved by the dislocation. An idiopathic dislocation (see Fig. 102) is mainly met with in cases of disease of the vitreous. The intimate connection between the zonule and the hyaline membrane of the vitreous brings about a i)articipation of the ligament in disease of the vitreous. Dislocation into the anterior chamber is not nearly so common. It mostly takes place in cases where the lens is small and cal- careous, but full-sized trans})arent lenses are occasionally dis- located in this direction. They often then remain transparent or semi-transparent for a long time. In a certain proportion of cases of dislocation of the clear lens forwards there has pre- Fio. 101. — Traumatic sul)luxation of lens with irregularly dilated pupil. viously existed congenital displacement. The two forms of dislocation described are very apt to set up irritation with in- creased intra-ocular tension. This is most likely to occur in the traumatic cases. As to treatment, interference is only called for when the condition gives rise to irritation. The dislocated lens should then be extracted. In order to do this successfully care should be taken to make a sufficiently large incision. Some vitreous generally escapes, too, but this cannot well be avoided. ISIore difficulty is experienced sometimes in the extraction of a back- wardly displaced lens. In such cases, after making a large incision, a scoop has usually to be used for removing the lens. Different methods of fixing the lens in some definite position ECTOPIA. 231 before extracting have been devised, but these as a rule are not necessary. Subconjunctival dislocation is only caused trauniatically. It occurs almost invariably in adults, in vi'hom the elasticity of the sclera is less than in young individuals. As a rule, if not invariably, the rupture of the sclera and escape of the lens take place upwards, and astonishingly little reaction follows the injury. There is generally a good deal of hi^jmorrhage at the time, so that the parts are not well seen, but the lens is easily made out, lying below the conjunctiva. When the wound in the sclera has healed, it has a dirty bluish colour, owing to an entanglement in the cicatrix of pigment from the ciliary body and iris. Fig. 102. — Case of idiopathic outward dislocation of the lens : ectopia lentis. The treatment consists in incising the conjunctiva, so as to permit of the escape of the lens. This should generally be done as soon as possible, especially if a portion of lens is included within the lips of the wound. Complete expulsion of the lens from the eye sometimes, though comparatively rarely, takes place as the result of accident. It is more common for it to escape through a large perforating ulcer of the cornea, after which the eye generally shrinks. Con,- '"""nyy^^KT^^ " Fig. 103. — From a case of cololioma of the lens. good, but the one produces more diplopia than the other. On the whole, the uniocular diplopia to which the condition gives rise is more evident Avhen the refraction is corrected than when no glass is worn. The improvement in vision is, however, in some cases very great, and the di})loi)ia soon ceases to cause any annoyance. Ectopia is due to a faulty development of one portion of the zonule. It probably always occurs in both eyes, and is frequently associated with a defect in the power of convergence. A traumatic dislocation into the anterior chamber is more likely to occur where there is a congenital displacement than where the lens is in its normal situation. Notwithstanding the dis- placement, the lenses remain transparent throughout life. COLOBOMA. 233 Two very much rarer malformations of the lenticular system are met with : — (1) Colohoma lentis, or a defect in the lens. This only occurs in cases where a large and continuous coloboma exists of the choroid as well. And (2) what has been called Lentico?ius, and described as a conical protrusion of the lens, very much resembling keratoconus. In lenticonus we find, on illuminating the pupil -with the ophthalmoscope, that every movement of the mirror causes crescentic lights and shadows to play round an enclosed circular area. Within this area, which is smaller than the pupil, retinoscopic shadows show myopia. Outside it there may be, and generally is found to be, hypermetropia. This appearance is apparently sometimes due to an unusual amount of sclerosis of the lens nucleus, which may be the cause of considerable visual defect. CHAPTER VIIT. DISEASES OF THE RETINA AND OPTIC NERVE. Diseases of the Retina. Very considerable physiological differences exist in the degree of vascularity of the retina, — that is, in the degree shown by the colour and appearance of the vessels. On this account, and also because the ophthalmoscopic magnification is not sufficiently great for the detection of small differences in the size of the vessels, it is impossible to draw a hard-and-fast line between the normal state, and deviations in the direction of antvmia on the one hand, and hypertemia on the other. For these reasons, too, as well as for others connected with peculiarities of the intra-ocular circulation, the observed condition of the retinal vessels does not afford by any means as delicate an indication, either of the state of the cerebral circulation, or of the heart, as might be, and indeed has been, supposed. When there is increased afflux of blood to the brain without collateral hypertemia, a similar afflux must take place to the ocular vessels. A passive hyper^emia of the brain, owing to impeded venous circulation, need not, however, affect the eye, as the ocular veins have other channels into which they can empty themselves besides the cerebral sinus, a thrombosis of which might therefore occur without influencing the circulation within the eye. When the venous impediment lies farther off, — in the jugular vein or in the thorax, — there will be at the .same time a visible interruption in the circulation within the eye. Interruption in the carotid circulation affects the eyes, although the anajmia which this causes may not be apparent. In aortic stenosis, for instance, by maintaining pressure with the finger on the eye while examining with the ophthalmoscope, the prolonged wave of pulsation can be well seen and distinguished from the .sharp beat which occurs under similar circumstances in normal conditions of the circulatiou. In aortic regurgitation there may PULSATION. 235 or may not be spontaneous i)ulsation of the retinal artery and vein. Thi.s depends on the degree of compensation, or on whether or not there are other complications ; if the mitral is also affected there is usually no pulsation. Venous 2iulsation is often seen, and most frequently on the disc. It is not necessarily indicative of any pathological condi- tion. It usually, indeed, depends upon some interruption in the vessel itself, where it bends suddenly round an artery or some part of the nerve. Spontaneous arterial 2}ulsation is pathological, and indicative either of some general circulatory disturbance, sometimes only increased cardiac action, or of increased intra-ocular tension. When there is increased tension alone, what is seen is a quick flash of blood rapidly distending one or more of the more or less collapsed arterial trunks on the disc, synchronously with each heart-beat. On the other hand, the pulsation sometimes, seen where there is some diseased condition of the aortic valve, is a comparatively gradual dilatation of the artery, producing often at the same time a visible movement of the vessel. This form of pulsation, too, is not confined to the trunks on the disc, but is often more distinctly seen at other parts, particularly where the vessels divide or make sharp turns. Vascular changes in the brain need only appear simultaneously in the eye when the cause of such changes is a central one, — ■ that is, due to irritation or paralysis of the vasomotor centre in the medulla. An increase or diminution in the amount of cerebro-spinal fluid, giving rise to altered conditions of the brain, need not affect the circulation in the eye, though such conditions may be followed by other ophthalmoscopic changes. The streak of reflection along the arteries is brighter the lighter the colour of the blood. Any marked oedematous condi- tion of the retina, such as that which occurs from embolism of the central artery or commotio retinte, causes the streak of re- flection to disappear more or less completely. It is absent, too, in detachment of the retina. Alterations in the size of the vessels occur in disease. Both arteries and veins may be either enlarged or diminished. It is most common, however, to find the calibre of the veins increased and that of the arteries diminished. Indeed, most inflammations of the retina cause this. Owing to localised phlebitis, some only of the retinal veins may be eidarged, and that often in an extreme degree. It is rare to find the arteries increased in size, whilst diminution in the size of the veins is only met with in the subsequent atrophic stages of retinal inflammation. 236 DISEASES OF THE P.ETINA AND OPTIC XErvVE. Sometimes, thougli very rarely, a formation of new vessels is seen to have taken place in the retina. Usually this, when it happens, is part of the process of organisation of an old blood clot. More frequently there may be seen leashes of small vessels passing into the vitreous and springing from the retinal vessels. The retinal vessels seem to be very little liable to aneurysm. Hjrperaemia of the retina. — As has already been said, it is not always quite easy to say that the a})parent congestion in any jjarticular case exceeds the bounds of physiological variation. In coming to a conclusion on this point, it is well to jiay atten- tion to the relative sizes of arteries and veins. The calibre of a retinal artery is never, under altogether normal conditions, much less than three-quarters that of the corresponding vein. Hyperajuiia in the retina, as elsewhere, may be active or passive. An active hy2jeraimia may be set up by all such con- ditions as call for any unusual straining of the eyes, such as reading in the dark, or prolonged attempts at deciphering diffi- cult manuscript or bad print. And this form of strain may be favoured, and more readily lead to congestion, when there is either some general weakness or some marked error of refraction which renders persistent exercise of this nature more irksome. As the normal relation in the size of the artery and vein is pretty well maintained in active hyperiemia, the diagnosis depends greatly on observing the state of congestion of the optic disc, which in such cases does not show so marked a con- trast in colour from the surrounding fundus as is usual. At the same time, however, there is no indistinctness of its margins, such as occurs w-hen inflammatory swelling of the papilla takes place. The cause of the deeper coloration of the disc is of course the springing more into view of the smaller vessels. Passive hy2)ermia and swelling of the papilla ; slight increase in the calibre of the 244 DISEASES OF THE RETINA AND OPTIC NERVE. veins and diminution in tliat of the arteries ; and diffuse oi)acity of the retina, with hiuiuorrliages, and the formation of white patches, which are confined at first to the region of the posterior pole. The changes in the papilla are at first very slight, and there is some opacity of the retina, and a few haemorrhages in the part surrounding the papilla. The hiemorrhages, too, are mostly deep and round, less frequently flame-sha}>ed. This a]> pearance is of itself suggestive of the kidneys being the cause, i)ut it is not absolutely characteristic. At a later stage white, and for the most part deep-seated, patches of fattily degenerated exudation make their appearance in the retina, while at the same time there is often some swelling added to the hyperiemia of the papilla. These white patches are mostly found in the region of the macula, where they are arranged in a star-shaped form, radiating out from the fovea. Around this central figure there are often a number of scattered spots of a similar nature. Such spots, too, are frequently to be seen in other parts of the fundus, surrounding, and never at a very great distance from, the disc. In some cases the patches round the disc become confluent, and thus form an extensive white area or circum- papillary zone, stretching up to the disc on all sides, and with an irregular margin towards the more healthy retina. Extensive offshoots from this zone then generally accompany the larger vessels. The vessels in the circumpapillary exudation are seen to be large and tortuous, and are here and there altogether masked by it. The retina is thickened, and there are usually large and numerous haemorrhages in the swollen white area. There is never any opacity of the vitreous. When these appear- ances are met with, they may be looked upon as practically characteristic of albuminuria. Little alteration may take place in the ophthalmoscopic pic- ture, even after a considerable time has elapsed. The patches and hjemorrhages may slowly clear away, or fresh ones become deposited. At an advanced stage of the disease the spots are sometimes very thickly scattered over the fundus, and here and there, more especially at the centre, a dirty greyish diffuse pigmentation may develop in them. Occasionally, too, the white reflection from the patches becomes intensely brilliant and metallic looking, owing to the development in them of cholesterin. At the same time the papilla and the retina may be very greatly swollen, so that at places the vessels entirely disappear from view. The retinal swelling sometimes gives rise to an appearance not unlike detachment. Most of the white patches lie in the deeper layers of the RETINITIS. 245 retina, the vessels of which may be seen to pass over them at places. Others are more superficial, and more or less com- pletely obscure portions of the vessels. Almost invariably both eyes are affected at or about the same time. The degree of blindness produced by albuminuric retinitis varies very much, and depends on the extent of the pathological changes at the macula. There is therefore often considerable difference in the visual acuity of the two eyes. The disease rarely causes complete blindness, but most frequently produces so much defect as to render reading impossible. The field Fxi-,. 108. — Extensive retinal iu ii o.i.^e ul iilliLimimuic lelmili.s at a late stage. of vision remains good, and also the colour vision. Sometimes the amount of visual defect does not coi'respond with, but is greater than can be accounted for by, the retinal changes. In such cases there may possibly be unemic poisoning of the visual centres. I have seen occasionally very marked deterioration occur without any apparent increase in the retinitis, followed after a few days by improvement. The 2)i'0(/nosis iu this disease is altogether gloomy, excei>t in cases such as the albuminuria of pi-egnancy, where the condition may be transitory. Some cases improve so as eventually to 246 DISEASES OF THE RETINA AND OPTIC NERVE. recover useful vision. Most remain pretty stationary, and die not long, generally not more than two years, after the onset of the retinitis. An extremely grave symptom is ajtparent detach- ment of the retina. Albuminuric retinitis is mostly met with in chronic cases of nejthritis. As the general symptoms are then often little marked, it not infrecpiently haj)pens that the diagnosis is first made with the ophthalmoscope. The treatment must be directed to the general disease which Fig. 109. — Diabetic retinitis, showing scattered exudations and hremorrliages. — After Wecker and Masselon. is the cause of the eye symptoms, the main indication being to relieve the kidneys by promoting the action of the bowels and skin. At the same time the usual precautions necessary in all deep-seated intlannnations of the eye must be taken, namely, shading from strong light and the avoidance of reading. Retinitis in diabetes. — In some cases of diabetes, mostly those of a severe type, there is a complication with retinitis. Diabetic retinitis is, however, rare when conqiared with the albuminitric form. Only when there is no albuminuria can the retinal RETINITIS PIGMENTOSA. 247 changes be safely ascribed to other conditions of the blood more directly connected with diabetes. The form of inflammation is not characteristic, and vei'y much resembles albuminuric retinitis, being, however, less severe, or at all events accompanied by less marked changes at the macula. The amblyopia produced varies very much from a slight defect of vision to complete blindness. The latter is due apparently only to complications : extensive haemorrhages into the vitreous or glaucoma. Opacities in the vitreous are frequent. The jn'oynosis, owing to the kind of case liable to be complicated by retinitis, is almost invariably bad. Retinitis pigmentosa. — A not very rare disease, the essential nature of which is, more correctly speaking, a sclerosis and pig- mentary degeneration of the retina than an inflammation, has received the name of retinitis pigmentosa. The disease is not associated with pigmentary alterations until it has advanced to a certain stage, and the pigmentation may indeed occasionally never make its appearance at all. Apart from the ophthalmoscopic changes, which are usually very characteristic, retinitis pigmentosa is accompanied by very definite subjective symptoms. These are — night blindness, which has usually begun in early childhood, and concentric limitation of the field of vision, with relatively good central vision. The ophthalmoscopic changes are — a very equable, greyish pallor of the papilla ; more or less marked narrowing of the vessels, both arteries and veins ; usually a conspicuous defect in the pigment of the hexagonal ceUs, which allows the choroidal vessels, with their pigmented interspaces, to come into view ; and a peculiar fine pigmentation in the retina. This pigmenta- tion takes the form of intensely black bone-corpuscle-shaped patches, usually in clo.se proximity to the vessels, and lying well forward in the retina (see Fig. 110). The pigmentation occurs mainly in a zone which lies midway between the centre and the periphery, and which is equally broad throughout. The breadth of the zone varies very much, being as a rule broader the more advanced and complete the sclerosis is. It generally approaches nearer the papilla on the inner than on the outer side, and in some cases patches may be seen quite up to the papilla. When very numerous, the thin filamentous processes of the pigment spots meet or come so close together as to form a network. The pigment comes from the layer of hexagonal cells, but is probably increased in amount by proliferation. The manner in which the vision is affected by this disease varies somewhat in different cases. As a rule, while there is a 248 DISEASES OF THE RETINA AND OPTIC NERVE. pretty marked and sonietinies excessive constriction of the field of vision, the central vision remains good enough for most purposes, — for reading fine print, etc., — yet it is only rarely that there is full normal vision. Usually the smaller the field of vision retained, the worse is the central vision. It is only com- paratively rarely that very small fields with good central vision are found, and in such the restriction may be observed to slowly increase without any marked difference in the central vision. Eventually blindness generally supervenes after the Fig. 110. — From a case of retinitis pigmentosa, showing interspaces owing to marked depigmentation. loroidal central vision has been destroyed, or a small eccentric portion of the field is alone left. In a good many cases in which there is marked concentric limitation, a portion of the temporal part of the field of vision towards the normal periphery may be found to have still retained some vision. Occasionally, too, a zone at the extreme periphery is left more or less unaffected, so that there is a broad band of the blindness, or a ring-shaped scotoma. Occasionally the pigmentation is almost confined to the macula, and there is then a central scotoma. RETINITIS PIGMENTOSA. 249 Altogether the pigmentation must be looked upon as having a subordinate significance in the changes which characterise this disease. The degree of blindness cannot be inferred from the extent of pigmentation. On the other hand, the pigment is only met with in places where the sclerosis of the retinal connective tissue, which is the essential factor, has taken place. Yet there may be a sclerosis in parts of the retina where no abnormal pigmentation or depigmentation is visible. This is the case mostly in the central portions of the retina. The process of Fig. 111. — From a case of retiuiti.s pigmentosa, in which the pigment is limited to the region of the macula. sclerosis may spread, and indeed most frequently does appear to spread, slowly from periphery to centre, so that the absence of pigmentation at the centre is often merely owing to the less ex- tensive alteration of the connective tissue there. In accordance with this, the central vision is relatively greatly better than the peri- pheral. But the presence of very constricted vessels and of great visual defect may be found with only peripheral pigmentation. The pigment has been proved to come only from that con- tained in the retinal pigment cells, in which, as one part of the 250 DISEASES OF THE RETINA AND OPTIC NERVE. ilogenerative process, a depigmentation has taken place. But there is no constant relation between this depigmentation and the amount of abnormal pigmentary deposition. This is very evident from the great differences seen with the ophthalmoscope (cf., e.g., Figs. 110 and 111). The depigmentation is merely an atrophy of the retinal pigment, the abnormal deposition an attraction of the hyperplastic connective tissue for the pigment which, probably to some extent, proliferates (though this is not certain) in the new situation. The two processes are to a great extent inde- pendent, though primarily occasioned by the same cause, — the sclerosis, — by which, too, the nerve elements, but not, or to a less extent, the nerve fibres, are destroyed. The restriction of the field ordinarily met with causes some difficulty in moving about, as patients Avith this defect are in much the same position as anyone looking through tubes held in front of either eye would be. Thus children frequently fall over things at their feet in a manner which to their parents appears, from their good vision otherwise, to be strange. The colour vision is good in retinitis pigmentosa, even in cases where the fields are very greatly restricted. The light sense is affected both with respect to the apprecia- tion of differences of intensity of illumination and to the vision in subdued light. The defect is most common and always most marked in the latter respect. It is this which causes the night blindness, which is a very early and very constant, though by no means invariable, symptom. Different degrees of the defect are met Avith. Often while the vision is so good in daylight as to cause no sort of discomfort, the patient is unable to guide him- self in the dusk, when the light is not so far reduced as to make any very appreciable difference to the normal eye. This defect is often popularly called " twilight blindness." Things are seen by artificial light only when pretty strongly illuminated ; thus while an individual might be able to read by the light of a candle, the surrounding objects in the room, which were only feebly illuminated, might be more or less invisible to him. In many cases the defect of vision produced by feeble illu- mination, though pronounced, is not nearly so bad as that just described, whilst in some it is hardly, if at all, noticeable. A form of stationary or very slowly progressive posterior polar cortical cataract is a pretty frequent accompaniment of retinitis pigmentosa. In the tyjtical cases there appear to be no further complications ; only where much the same retinal changes are met with, following inflammation from acquired or inherited syphilis, may there be more or less manifest altera- RETINITIS PIGMENTOSA. 251 tions in the choroid, or iris as well. In such cases, too, the retinal pigmentation is rarely if ever so equally distributed as in the true disease. There is sometimes a little difficulty in distinguishing between cases of primary retinal sclerosis with pigmentation, and pig- mentation of the retina which is secondary to choroiditis. Some cases of retinitis pigmentosa are atypical with respect to the picture presented by the pigmentation. The patches, instead of being more or less closely placed or interlaced, bone-corpuscle- shaped, and following the course of the blood vessels and capil- laries, are in the form of irregular, roundish, small masses, distributed, apparently without any definite arrangement, in the deeper parts of the retina. The only difference in the pathology of those cases seems to be that the sclerosis and imbibition of pigment is more confined to the connective tissue framework of the retina, and less marked in the perivascular connective tissue, than is mostly characteristic of the process. In other respects, and especially in the absence of any choroidal changes, there is no reason why such cases should be mistaken for later stages of choroidal inflammations. Retinitis pigmentosa is almost invariably bilateral. The disease begins either congenitally or in early childhood ; occa- sionally not till some years after puberty. Some cases of congenital blindness, too, appear to be of the same nature. The pigmentation is probably never met with at birth, but usually makes its appearance during the first few years of life. The disease is considerably more frequent in the male than in the female sex. It is unquestionably hereditary, and, just as in all other affections where this is the case, there is often consan- guinity in the parents or grandparents. Often several members of the same family are affected, rarely if ever all. Congenital deaf-mutism and idiocy are not seldom met with in the sub- jects of retinitis pigmentosa. Sometimes deafness comes on later. The cause of the disease is altogether unknown. The fact that very similar appearances follow syphilitic inflammation is certainly suggestive of syphilis as a cause ; yet it appears pretty certain that this is not the case. ISIost cases progress exceed- ingly slowly, and even remain for longer or shorter periods apparently absolutely stationary. No treatment that has hitherto been tried can be said to be of the slightest avail. Atypical forms of retinal sclerosis occur. There are, e.ff., cases in which, along with an absence of any characteristic pigmentary changes, the appearance of the papilla, as well as the sub- 252 ]JI8EA8ES OF THE RETINA AND OPTIC NERVE. jective symptoms, are identical witli what is found in retinitis pignu'iitosa. Congenital pigmentation of the retina. — A ])eculiar form of Fig. 112. — Congeuitiil pigmeiitiition ol tlie retina (from a case of Mr. Sydney Stephenson's). retinal pigmentation, which appears to be congenital, is sometimes met with. In these cases small irregularly-shaped groups of pigment occupy some sector of the retina. Retinitis proliferans.— This name has been given by Manz EMBOLISM. 253 to a very unusual form of chronic inflammation of the retina. After a longer or shorter jieriod of defective vision, the appa- rent cause of which is hcemorrhagic opacity of the vitreous, there may be seen, covering more or less completely the papilla and extending over the surrounding retina, a markedly prominent and deeply folded or furrowed bluish opacity. This fibrous or membranous looking opacity follows the course of the large vessels, which it to a great extent hides, but in the furrows may be seen vessels apparently newly formed. In the region about the main mass of connective tissue which this central opacity represents, may generally be seen whitish thread-like opacities stretching farther towards the periphery of the retina. These are no doubt vessels surrounded by a dense opacity caused by perivasculitis. Haemorrhages into the vitreous seem always to accompany this affection ; and these, along with the cataract, which may subsequently make its appearance, make the image which it is possible to obtain with the ophthalmoscope as a rule not very distinct. No treatment can be said to be of any use. Embolism of the central artery of the retina. — It is only rarely that the circulation is completely stopped in the retinal vessels ; when this is the case, no pulsation can be obtained in the artery by pressure on the eye. The diminished supply of blood flowing into the eye causes the arteries to appear smaller, while at the same time the streak of reflected light along them becomes less apparent, or is altogether absent. The veins, too, may be smaller than normal, though this is usually the case only with those portions which are on and near the disc. They are often rather distended farther towards the periphery, and taper towards the disc. The ischcemia is rendered further apparent, too, by the invisibility of the smaller vessels. What looks like, and is often described as, spontaneous pulsation may be seen in the arteries, due to the partial interruption of the blood flowing into them, producing with every systole a more or less marked difference in the degree of their distension. The intermittent passage of broken columns of blood may sometimes be observed in the veins when the circulation is not altogether, but all but, stopped. Besides the varying appearances met with in the vessels indi- cative of circulatory impediments, an embolism of the central artery produces other and more characteristic changes in the retina. These, however, last only a short time. The central portion presents a whitish opaque appearance, not unlike the bloom on fruit. This appearance is due to fedema. It is niost 254 DISEASES OE TTTE llETTNA AND OPTIC NERVE. iiitt'iise loiuid tlie iiiacula and optic nerve, and often indeed luudly aj>pn'('ial)le elsewliere. As a rule, too, in the area occujiied by the ( edema it does not ])resent an equal density or opacity throughout, but the whiteness tends to fade ott' at about equal distances from the papilla and macula. Thus, midway between the macula and the disc, it is seldom if ever so dense as in the vicinity of either. The oedema has, too, a more streaky appearance round the disc. At the centre of the macula, and corresponding in position to the fovea centralis, there is no opacity. Owing to this, the appearance presented by this portion of the retina is very remarkable, and generally described Fifi. 113. — From a case of einbolisiu of the central artery of the retina.— After Jaeger. as a cherry red spot. So strong is the contrast between the colour of the fovea and the surrounding retina, that this appear- ance cannot fail to at once attract attention. The cherry red spot in the middle of the oedematous opaque retina, when taken along with the history of sudden and spontaneous loss of sight, is perfectly characteristic of an interruption in the circulation. Whether the interruption in the circulation in any given case is due to embolism of the artery, or to thrombosis in the vein, or haemorrhage into the sheath of the nerve, causing compression of the nerve and vessels, is not always easy to determine. The EMBOLISM. 255 subjective symptoms are the same in all causes of interruption. Haemorrhages are much more numerous in cases of thrombosis than they are where the interruption is embolic. The ffidema of the retina does not come on immediately on the plugging of the vessels, and takes several hours, or even a day or two, to reach its height. It then slowly passes off, leav- ing no trace after a week or two. The diagnosis may not then be so easy unless the appearances in the vessels are marked. Fio. 114.- -Froiii a case of embolism of the ilesceudiiig branch of the central artery, sliowiug oedema of the retina. It will depend more on the history and the nature of the visual defect. Embolism of the central artery causes sudden, and in most cases all but complete, and permanent blindness. The suddenness of the blindness produced by the cutting off of the blood supply to the retina is a remarkable illustration of the close dependence of its functional activity on its blood supply. The absence of anastomosis with other trunks, too, is the cause of the blindness remaining permanent, so that only where the plugging is incomplete from the first can any sub- 25G DISEASES OF THE RETINA AND OPTIC NERVE. secjuent improvement 1)6 looked for. In a number of cases a small portion of the temporal side of the field of vision retains some vision. Occasionally the embolism, instead of settling in the main trunk, may ping one of the branches of the central artery. There is then produced a defect in the field of vision corre- sponding to the portion of retina supplied by the plugged vessel. This is a much rarer accident than embolism of the trunk. In most cases that I have seen, a portion of the field has been ])ermanently lost right up to the jieriphery, and a sharp line of demarcation has existed between the blind and seeing areas, with retention of sharp central vision. The corresponding artery has also been visibly constricted, or even practically obliterated. It is possible that this appearance may sometimes be due to localised spasmodic constriction of retinal arteries. Probably in most cases of embolism there is some affection of the heart, but it is not always possible to diagnose this with certainty. Both eyes are never blinded at the same time, and cases in which the accident happens first in one and then in the other are of extreme rarity. While the 2^^'ogn')sis is therefore absolutely bad as regards the affected eye, the other may be looked upon as perfectly safe. There is more danger of embolism occurring elsewhere, and leading to other j^aralysis. Very little can be done in the way of treatment for embolism in the retinal arteries. Kneading or massage of the eye is recommended, and is said to have dislodged the clot and led to improvement in a few cases. Iridectomy and paracentesis of the aqueous chamber have also been recommended, with the object of rapidly reducing the intra-ocular tension. Detachment of the retina. — Cases in which, either as the result of accident or of disease, the retina becomes detached from the choroid are of pretty frequent occurrence. The separa- tion takes place between the hexagonal pigment layer and the layer of rods and cones, the former remaining attached to the choroid. Detachment of the retina may be primary, that is to say, unaccompanied by any apparent inflammation, or secondary to affections such as cyclitis, which gradually lead to shrinking of the eye. Tumours springing from the choroid, too, give rise to detachment. In traumatic cases the separation may take place at once, or not until some time has elapsed. Idiopathic detach- ment of the retina comes on either suddenly or gradually ; the first is morg common, DETACHMENT OF THE RETINA. 257 The objective appearances met with are usually sufficiently characteristic to render the diagnosis with the aid of the ophthalmoscope easy. Occasionally, owing to transparency of the detached portion, or to this circumstance combined with shallowness and small extent of the detachment, the nature of the disease can only be made out with certainty by very care- ful examination. Often, too, a difficulty in the ophthalmoscopic diagnosis may arise from the presence of opacities in the lens or vitreous. The diagnosis is made by observing that some portion Fig. llii. — Detaclinieut of retina. of the fundus is seen to disappear suddenly out of focus, and often at the same to be altered in colour, sometimes to a bluish, at others to a greenish gi-ey, according to the manner in which the light is reflected from its surface. When the vessels on the surface of this detached portion arc focussed for, they appear darker by direct examination, and often smaller than normal. When the retina remains clear, owing to the absence of any turbidity of the licjuid l^ehind it, no indication may be aftbrded by alteration of colour. The diagnosis will then dei)end upon one's finding an area which, in order to be distinctly seen, 17 258 DISEASES OF THE RETINA AXD OPTIC NERVE. requires an alteration in the focu.s. At the same time the vessels over this more hyi)ermetropic area are blacker than in the immediate neighbourhood where the retina is in position. A parallactic movement of the vessels over the red fundus can often be made out too, more especially if a choroidal vessel can be seen behind the detachment. At some portion of the detached retina there may be often seen a rent or rupture in it. This varies very much in size and has a very characteristic appearance, allowing the choroid to be seen with perfect distinctness through the ojjening. The margins of the rent may sometimes be seen turned in towards the vitreous. In some cases, especially where the detachment has been hajmorrhagic, there may be seen irregularly disposed straw- coloured striaj or star-shaped opacities in the retina. These might be taken for scars, did they not frec[uently ajjpear to interlace and lie behind perfectly intact vessels. They are in all probability fibrinous deposits at the back of the membrane. In almost all cases where the detachment has existed for some time, and is not produced by tumour, the intra-ocular tension is found to be diminished. The subjective si/mptoms vary according to the portion of the retina detached, the state of vision in the other eye, and the rapidity with which the detachment is developed. They are- defective central and peripheral vision, metamorphopsia, and night blindness. Often for a longer or shorter period, before any actual displacement has taken place, the patient complains of muscas or black spots of different shapes and sizes floating in front of his eyes, and of subjective light sensations, flashes, and rays of light, coloured as well as uncoloured. When the detach- ment does occur, he is often conscious of a cloud coming in front of his field of vision. This is more likely to be observed in cases which come on suddenly and in which the vision of the other eye is lost. It is almost always noticed where the detach- ment is caused by tumour, as in such cases the central vision is, as a rule, relatively much better than in those in which the disease is idiopathic. At the same time the outlines of objects appear distorted. The apparent irregularity, too, which they present is apt to be inconstant, and to change much like the images reflected from the wavy .surface of disturbed water. The distorted objects often appear to be boixlered by colour. There is usually more or less night blindness produced, both the light mininuim and light difference being greatly reduced. There is often a remarkable tendency to confuse between blue and m-een. DETACHMENT OF THE RETINA. 259 In cases of detached retina, where the condition has lasted for some time, there is usually a marked coutractiou in the field of vision corresponding to the portion of retina detached. As the recently detached retina retains its function to some extent, the restriction of the field in fresh cases may often escape observation unless the examination is made in subdued light. The boundaries for peripheral colour vision are narrower than the line separating the undetached from the detached portion of the retina, that is to say, the field of vision is more restricted for colours than for white light. The defect in the field of vision has most frequently a more or less indefinite, ill-defined, and irregular boundary. If the field be at first restricted below, which is frequently the case, an extension upwards of the restriction is not unlikely to follow, corresponding to the tendency to gravitation of the subretinal liquid. In this exten- sion, either or both sides of the field in the neighbourhood of the point of fixation may be involved, even the fixation point itself. In almost all cases of simple detachment of the retina the central visual acuity is more or less diminished. This is often due, no doubt, to an oedematous condition at the macula. When the detachment is caused by tumour, the defect in the field is usually much more sharply defined, whilst the central vision may remain unaffected. This point may be of some diagnostic importance in a douljtful case. When detachment of the retina occurs idiopathically, it is frequently found in both eyes. Only occasionally, however, does the detachment occur simultaneously, or nearly so, in the two eyes. Generally a considerable time, often many years, elapses before the second is affected. The occurrence of subjec- tive light and colour sensations, and a notable increase in the number of muscte, is always a suspicious circumstance. Detachment of the retina is more frequent in old than in young individuals, the number of cases increasing with each decade, up to sixty at all events. It occurs in eyes presenting all the dift'erent states of I'efraction. In rather more than sixty per cent, there is myopia. The I'etina may be detached at any part, but in a large pro- portion of cases some part of the upper half is detached. Cases which have existed for some time are very often com- plicated with cataract, and the opaque lens not infrequently undergoes subsequent calcareous degeneration. Opacities in the vitreous are sometimes met with too, and this is almost always the case where the detachment has been caused by haemorrhage, 2G0 DISEASES OF THE llETINA AND OPTIC NERVE. either spontaneous or following injury to the eye. In these cases the opacities are often membranous. The ]n-of/nosis in detachment of the retina is always bad. Most cases go on to complete blindness, but, as a rule, in idio- pathic cases the eye retains its shape and does not give trouble. Sometimes inflammatory changes make their appearance, and end in shrinking of the globe ; at other times the subjective sensa- tions give rise to nnich discomfort. In a very few cases im- FiG. 116. — From a rase of detaehinent ot the letiua, showing rent. provement takes i)lace owing to the retina becoming reapplied, but even after this is permanent the vision is not fully restored. All that one could possibly expect, indeed, would be for the detached portion to adhere sufficiently firmly to prevent the hitherto undetached jiart becoming separated, and allow of the improvement taking place in it which might be possible from the disappearance of any cedema. The prognosis is decidedly OPAQUE NERVE FIBRES IN THE RETINA. 261 more favourable in the case of young individuals. After sixty it is j^ractically hopeless. The treatment of detached retina has hitherto been very unsatisfactory. The fact that in some cases the retina does become temporarily or permanently reapplied if the detachment is recent, suggests the advisability of keeping the patient for some weeks lying on his back. It is customary to combine this with pilocarpine injections, or with other means of promoting absorption. Removal of the subretinal licpiid by puncture through the sclera has also often been tried, but without any marked permanent success. A constant drainage of the sub- retinal space by means of a piece of gold wire left sticking through the sclera was for some time tried by Wecker, also unsucessfully. Schuler claims to have obtained good results by injecting a drop or two of tincture of iodine into the vitreous. Those who have followed him in this treatment have not been able to confirm his statements with regard to it. So far as the method has as yet been developed, it appears to be not only uncertain but even dangerous. Detachment of the retina is, nevertheless, one of the few diseases of the fundus which we may not unreasonably hojie some day to be able to check in some measu.re or prevent by active treatment. I have obtained the best results by repeated punctures made with a Graefe's knife pushed through from one side of the eye to the other in the region of the detachment. This is, I consider, always worth trying in young people. It is useless in complete detachment and in old people. Opaque nerve fibres in the retina. — As they pass through the lamina cribrosa, the fibres of the optic nerve become divested of their myeline sheath. This accounts both for the compara- tively small diameter of the papilla, and for the transparency of the hbres as they stretch over and form part of the retina. In some cases, and in all probability as a congenital anomaly, because the myeline sheath is developed around the fibres of the optic nerve before birth, some of the fibres in the retina are rendered intransparent l)y being provided with a myeline cover- ing. The appearance which this abnormality presents is very characteristic. It is seen as a brilliantly white patch, mostly extending from the upper or lower edge of the disc, sometimes from both at the same time. This patch almost invariably comes up to the margin of the disc, so as to appear quite con- tinuous with it, while at its perijjheral end it is less strongly defined, presenting a striated appearance owing to the sheaths of the fibres endinsj at diftereut distances from their origin. 2G2 DISEASES OF THE RETINA AND OPTIC NERVE. The patch is rarely as big as the disc itself ; when bigger, it curves round over the macula. Occasionally a detached portion, at some distance from the i)apilla, has been seen, in which case the nerves after having lost their sheaths have again regained them. The vessels are almost always here and there hidden by the oitatjue fil)res. Whether this is or is not the case dej tends partly on the depth and jtartly on the degree of opacity of the sheathed fibres. There is little difficulty in diagnosing patches due to opaque Fig. 117.— Opaijue uervu lilires. — Alter FiiO.-iT. nerve iilires from iuHaiuniatory exudations in the retina. The latter are usually of a less dense white ; they do not present the same striated appearance at their peripheral ends, do not come into such immediate contact with the margins of the disc, and are besides associated with hypera?mia, and often htemorrhages, at other parts. I have seen the two conditions present at the same time without rendering the diagnosis difficult. Oi>aque nerve fibres may occur in one or both eyes — more frequently, I think, only in one. They do not give rise to any defect of vision, further than as a rule some corresponding OPTIC NEURITIS. 263 degree of extension in the size of the blind spot. They are met with as the normal condition in some of the lower animals. In man they are nncommon, though by no means very rare. Retinal changes produced by strong light. — Very persistent after-images may be produced by looking at the sun or a strong electric light. If the exposure has not been too prolonged, the defect of sight thus caused may be recovered from. A prolonged exposure gives rise to a coagulation at the macula, with the appearance of a small irregular })atch in that region, and the production of a persistent central scotoma. Less strong sources of light also give rise to macular changes. I have seen such produced by constant use of the microscope. The changes in these cases appear to be more of the nature of small hajmor- rhages at the macula. Sometimes they are apparently, in the less severe cases, mere temporary alterations in the arrangement of the pigment at the fovea. They may give rise to consider- able central amblyopia with metamorphopsia, but the vision is usually slowly regained. Diseases of the Optic Nerve. Optic neuritis. — Inflammation of the optic nerve occurs either alone, when it is often called j)apil/itis, or along with more or less intiammation of the surrounding retina — neuro- retinitis. Papillitis is most frequently connected with some pathological change within the cranium ; but such changes often lead to neuro-retinitis as well. * It is characterised by more or less intense passive hyperajmia and swelling. The veins are engorged sometimes to an excessive degree, while the arteries, on the other hand, are normal in calibre or narrowed. The colour of the whole papilla is heightened, and the swelling causes it to become prominent, so that its surface is on a different level from that of the retina, while its margins, instead of being sharply defined, are more or less obliterated. The swollen nerve tissue also gives rise here and there to the disappearance of the vessels in the papilla, and these may be seen to dip abruptly at its margins as they continue their course in the retina. This obliteration of the margin of the disc is usually first noticed at its upper and lower edge, sometimes only to the nasal side. Often a very distinct striation can be made out on the swollen papilla as the bundles of swollen fibres are brought more prominently into view. There is at the same time more or less marked loss of transparency of the nerve tissue, and an increase, iiG4 DISEASES OF THE JtETLNA AND Ol'TIC NEllVE. often con.sidcral)le, in the size of the disc. The degree of prominence of the swollen papilla can be appreciated by observing the difference in the strength of the glass, which is necessary to focus accurately the surface of the disc and the surrounding retina, and allowing roughly one millimetre for every three dioptres. The extent of parallactic movement gives a very good idea of the intensity of the swelling. The amount of swelling met with is very varial)Ie, and the time taken for the development of these changes ^'ery dirt'erent. Fi<;. lis.— Karly stai. if (iiitic iR'uritis A considerable degree of i)ajiillitis may exist without inter- fering to any ap})reciable extent with the functions of the eye. The central and perijiheral vision for both form and colour may be perfect. Sometimes the absence of any subjective symptoms lasts for months, but as a rule it is not long before the visual acuity becomes more or less reduced, and the sight may indeed be altogether lost. When such loss of vision occurs pretty suddenly, it should always arouse the suspicion of there being some other cause for it besides the swelling in the papilla. The gradual loss of vision is no doubt due to OPTIC NEURITIS. 265 compression of the nerve fibres in the jiapilla, by the gradual changes which the intianimatory exudation undergoes. An abseiice of visual disturbance at first aftbrds no guarantee that such will not afterwards come on. When the central vision is affected, there is almost always at the same time a more or less concentric limitation of the field of vision, with greater or less loss of colour vision. Sometimes the restriction of the field is more irregular, aftecting often the nasal half of the field more markedly than the temi»oral. The blind spot may be found to Fig. 119.— Latfi- .-ta-t- olOptir iifuiitis. be increased in size, especially if the test object be small and not very bright. The light-difference sense is diminished, but there is no night blindness. Encephalopathic papillitis is jiractically always bilateral. The condition of swelling of the papilla in which an accumula- tion of liquid in the sheath is supi)osed to be present, is often called choked disc. There are of cour.se great differences in the degite of inflammation in different ca.ses, but these differences are not due to essential differences in the etiology. Not all pathological processes in the brain give rise to optic 266 DISEASES OF THE RETINA AND OPTIC NERVE. neuritis. It occurs most frccjuently with tumours ; indeed, so frequent is this association, that its recognition must be looked upon as a factor of primary importance in the diagnosis of cerebral tumour. Next in jtoint of frequency comes neuritis along with meningitis. Some cases of hydrocephalus are asso- ciated with optic neuritis. More frequently a simple atrophy of the nerves is found in this connection. It is seen too, occasionally, in connection with purulent inflammation of the middle ear, when the inflammation has spread to the brain. Papillitis is rare altogether in cases of abscess of the brain. It is not met with in cerebral apoplexies, or in softening due to thrombosis. There ai)pears to be no invariable connection between the acuteness of the cerebral and ocular symptoms. A chronic neuritis jirobably signifies chronicity of the affection in the brain ; while, on the other hand, an acute neuritis may be set up by chronic as well as acute disease. After existing for a longer or shorter time, the neuritic process as a rule passes on to atrophy of the nerve, with more or less complete destruction of sight. Most frequently the blindness thus produced is eventually complete, and this may occur long before the brain disease leads to the death of the patient. At other times, after having progressed to a certain extent, the process remains stationary, and some degree of sight is left. This is more often the case in children than in adults, and mostly when the neuritis is originally connected with meningitis, in which cases it is generally less severe than when set up by tumour. Some cases of neuritis get well without undergoing any, or only very slight traces of, atrophy. Mostly such cases have retained good vision throughout the period of inflammation, and only in such have I seen this practically complete recovery ; but it appears undoubted that the vision, though defective at the time of the neuritis, may be restored without being permanently damaged by any subsequent atroi)hic process. Tumours in the orbit, and inflammatory processes which have either begun in the orbit or spread into it from surrounding parts, may give rise, along with proptosis, to optic neuritis. As a rule, the swelling in the nerve is not so intense as in cases connected with tumours in the brain, and often a considerable acuity of vision may be retained, notwithstanding a high degree of protrusion. Deformities of the skull, owing probably to pressure on the nerve at the optic foramen, may be the cause of neuritis. OPTIC NEURITIS. 267 A number of cases of neuritis are altogether unconnected with disease either in the cranium or orbit. The etiology in such cases is often not very easily made out. They may occur after severe illnesses, without there being any definite connection between the particular disease and the neuritis. Other nerves may be affected at the same time ; it is found, for instance, as one of the symptoms of more generalised neuritis. Syphilis, exposure to cold when there is more or less of a rheumatic dis- position, and menstrual disturbances (particularly amenorrhcea and sudden suppression) all appear to be of undoubted causal influence. In all such cases, and especially in the more acute forms, the prognosis is on the whole much better than where the neuritis is merely a secondary manifestation. Even in cases where almost total blindness has been produced by the inflamma- tion, a complete, or nearly complete, recovery may take place. Often a high degree of amblyopia, with or without restriction of the field of vision, is left. An interesting and peculiar clinical type of optic neuritis is one which comes on generally shortly after puberty, almost exclusively in young men, and without there being any apparent immediate cause, other than a more or less markedly neurotic temperament. In such cases there is usually distinct evidence of heredity, several members of a family being affected. It always occurs in both eyes, causing, generally pretty suddenly, considerable blindness, first of the one eye and then of the other. The central vision is sometimes so much destroyed as to give rise to an almost absolute central scotoma, from Avhich the patient does not as a rule recover. The objective symptoms are much like other cases of neuritis — they are rarely very pronounced, but there is usually well-marked perivasculitis. The pathology of these cases is probably very closely allied to a not by any means uncommon, yet not very sharply defined, group of cases, which are generally looked upon as of the nature of retrobulbar neuritis. The characteristics of this group are — comparatively slight changes in the papilla, and the presence of a more or less definite central scotoma. The changes in the papilla may be so slight as altogether to escape detection, or they may amount to merely some slight haziness of its margins, and perhaps a trace of perivascular inflammation. After some time the outer half of the disc may exhibit an abnormal degree of pallor, whilst at the same time the contrast between it and the nasal half may be increased by some degree of injection of the latter. At other times a more general pallor of the disc results. 2GS DISEASES OF THE llETINA AND OPTIC NERVE. The central scotoma has often very much the same form as that which characterises toxic amblyopia, but it may differ from it in an inn»ortant manner both in shai)e and extent. Just as in these cases, it is usually negative, — that is to say, it does not give rise to the sensation of any dark spot. Often a faint cloudiness is complained of in a Vjright light, and on account of this patients freipicntly state that they see better in a subdued light. On examination, however, this does not jirove to be the case. At other times a more or less dark, generally buff- coloured, mist is comitlained of. The colour defect, too, in the region of the scotoma is much the same as in the toxic amlilyopia. The scotoma does not present, however, the same regularity of shape, and is not confined to the area stretching from the disc to the macula to that area which is supplied by the papillo-macular fibres, changes in which have been shown to exist in certain cases of toxic amblyopia. A point of consideraljle importance is the frequent extension of the afi'ected area considerably to the inner side of the point of fixation, a condition which is not met with in typical cases of toxic amblyopia. At the same time in many cases there is some concentric limitation of the field of vision. Both eyes may be affected, but much more frequently only one. Where the disease is bilateral, it rarely gives rise to the same degree of amblyopia in the two eyes. It is about eijually common in men and women. Diaf/nosis. — The disease with which it is most likely to be confounded is the much more common toxic amblyopia. This mistake is not likely to be made except in bilateral cases. Even in one-sided cases the loss of sight of the other eye from some difterent cause may lead to this difficulty. The points to be attended to in the diftereutial diagnosis are mainly- — the irregular shape of the scotoma, more particularly its marked extension when large to the nasal side of the point of fixation ; and the peripheral restriction of the field of vision. In some cases there is more or less {)ain complained of on moving the eye, or pro- duced by pressing the eye back into the orbit. Generally, too, the i)ain is most marked when the eye is moved in some par- ticular direction. The prognosis is much less favourable than in toxic amblyopia. Some cases go on to complete blindness, others are left with an absolute central scotoma and the 02:>hthalmoscopic appearances of ojitic atrophy. A certain proportion — not quite half probably, and these the more acute and less severe cases — recover in a few weeks from the onset of the disease. There can be no doubt ATROPHY OF THE OPTIC NERVE. 269 that the symptoms are produced by a superficial inflammation of the nerve in the orbit. In the treatment of optic neuritis the cause has in the first place to be taken into consideration. Some cases depending on intra-cranial tumour have been relieved by the removal of the tumour. As far as any possible effect of such treatment on the vision goes, it has of course to be undertaken before the inflam- matory changes in the nerve have proceeded too far. Removal of the liquid from the sheath of the optic nerve was recom- mended by Wecker as far back as 1872, but has not received much attention. Atrophy of the optic nerve. — Atrophy of the optic nerve may he primary, — that is to say, it may originate in the nerve itself, or it may be secondary to changes which have occurred either in the retina or in the central nervous system. The atrophy may, as we have seen, follow inflammation ; it is then usually termed post-neuritic or post-papillitic atrophy ; or it may be simply due to degenerative processes of different natures. The ophthalmoscopic appearances are — pallor of the disc, often accompanied by some degree of excavation, and by narrowing of the calibre of the vessels. The scleral ring is generally more than usually well marked, owing no doubt to some degree of shrivelling or contraction, which only rarely gives rise to any distinct diminution in the size of the disc. The loss of colour in the disc, which first becomes marked as a rule to its outer side, is due partly to diminution of vascularity, and partly to disappearance of the nerve tissue, leaving only the white con- nective tissue, often increased in amount, behind. When this is the case, there is produced a shallow excavation, known as an atrophic excavation. From the mere colour of the disc, without taking into con- sideration the size of the vessels and the existence of an excava- tion of this nature, it would be rash to conclude that there was atrophy, unless perhaj)S the light reflected from its surface had not only lost all tinge of yellow or pink, but also become bluish or greenish in hue. Consideraljle variations take place with respect to colour within physiological limits ; a very anaemic condition of the disc may, too, although it may hardly be normal, exist without any, or any great, functional disturbance, and yet not be of the nature of atrophy. Great pallor, with loss of transparency of the disc, due to consolidation of some exuded matter, is found in cases in which a neuritis has been completely recovered from, and not followed by atrophy. Even when the ophthalmoscopic appearances — 2)allor, excava 270 DT8EASE8 OF THE RETINA AND OPTIC NERVE. tioii, and narrowing of the vessels — leave no doubt as to the existence of an atroi»hic process, it is impossible to say, with any degree of certainty, from a consideration of the picture thus l)resented to one, whether the process is a progressive one or not. When the atrophy is evidently post-neuritic, the chances of its becoming arrested at some stage short of complete blindness are generally greater than when it is the result of a more distinc- tively degenerative change. Post-neuritic atrophy is character- ised by more or less indistinctness and want of definition of the margins of the disc, and in many cases by white patches on its surface. These patches stretch between, and sometimes cover, the bifurcations of the vessels, and extend along the main trunks as white lines. This condition of perivasculitis is often not confined to the disc alone, but extends for a greater or less distance along the vessels into the retina. A good deal more light is often thrown on the question as to whether in any given case the atrophy is likely to l)e progressive or not — that is to say, is likely to progress to such an extent as eventually to destroy vision — by a careful examination of the subjective symptoms caused by the degeneration. These symp- toms are — defects in the central vision, restrictions of the field of vision, and defects in the colour and light sense. In all cases where the atrophic process in the nerve is primary, or due to some interruption at any part of its course, and not secondary to alterations in the choroid and retina, there is no interference with the light-minimum sense. On the other hand, the power of distinguishing between intensities of illumination is less acute than normal, often indeed very markedly so. Such a defect of the light sense is characteristic of any affection originating in, or mainly implicating, the nerve tissue itself. The most common form of restriction of the field in atrophy is the concentric. Often, however, the defect in one direction may be much greater than in others ; and when this is the case, it not infrequently happens that a good deal of symmetry in this respect is to be found in both eyes, even although the atrophy may be nuich more advanced in the one than in the other. In all cases of progressive atrophy, the restriction which is taking place can probably be most easily demonstrated for colours. This is mainly because, if the examination is made in ordinary daylight, the corresponding failure of the sense of form may, if slight, more readily escape detection. If the test is made by Bjerrum's method with very small objects (see Chap. II.), the restriction for form can always be demonstrated. ATROPHY OF THE OPTIC NERVE. 271 There seems every reason to sujipose that the colour defect in progressive atrophy is accounted for by the relatively greater perfection of conductibility which is necessary for the trans- mission of stimuli destined to give rise to colour sensation. Colour tests are therefore more delicate tests for the detection of diminished conduction than the commonly applied tests for the sense of form. Restriction of the field vision, when more or less concentric, and especially when the colour defect is pronounced, is always very suf/f/estive of progression. Usually the defect of central vision keeps pace with the gradual narrowing of the field, so that when there is much restriction there is generally at the same time considerable amblyopia. In some cases the central vision remains relatively very good, but it is seldom that this can be looked upon as a good sign, — in fact, the prognosis mainly depends on the state of the peripheral vision. In the same way, if during the pro- gress of a case it is found that the vision gets no worse for some time, this is only a favourable sign if at the same time the state of the field remains stationary as well. Some cases, particularly when the atrophy results from neuritis, progress to a certain extent, leading to both restriction of the field of vision and defective central vision, and then become arrested. In all cases where there is merely a central scotoma, xvithout any narroiving of the field, the prognosis is good, — that is to say, the scotoma may become absolute, but vision is not likely eventually to be lost altogether, notwithstanding the objective appearances. Neither from the ophthalmoscopic changes nor from any peculiarities in the symptoms does it seem possible to diagnose the cause of the atrophy without taking into consideration other circumstances. An atrophy due to spinal disease is often, though not always, complicated at the time of examination by ataxic or other spinal symptoms, or by abnormalities in con- nection with the pupil, loss of knee-jerk, etc. ; one which is con- nected with cerebral disease is frequently followed, though rarely preceded, by mental derangements. Some of the primary de- generative changes in the optic nerve, which are always bilateral, are local expressions of the same conditions which give rise to tabes, and as such may precede the other symptoms. They are not extensions, but independent degenerations. Sometimes the degeneration begins at the central terminations, at other times at more peripheral parts of the optic nerves. Apart from what has been shown to exist anatomically, Nettleship considers that 272 DISEASES OF THE RETINA AND OPTIC NERVE. tlie absence of pro-atropliic anil)lyoj)ia affords strong clinical evidence of the periplieral and entirely isolated nature of the degeneration, which in cases of tabes leads to progressive atrophy. In other cases the atroi)hy appears to be altogether unconnected with any similar process elsewhere ; it is at all events not, even after the lapse of many years, followed by any changes in the central nervous system. Yet it may perhaps be looked upon as not impro])ably a manifestation of the same disease. Unilateral atrophies are generally the result of some process originating either in the retina or the orl)it, but they may be caused by compression within the cranium either of the nerve or of the vessels supplying it. The latter cause may be sus})ected when there is mai'ked evidence of arterio-sclerosis elsewhere. Of the bilateral forms of cerebro-spinal origin some idea of the process giving rise to them may be gathered from the ophthalmoscopic appearances ; thus the opaque-looking atrophic degeneration, with narrowing of the vessels, points to changes mainly involving the connective tissue and destroying the nerve elements. It may be taken as a general rule — to which, how- ever, there are exceptions — that degenerative processes beginning at the base of the brain, while they lead to pallor, are not asso- ciated with diminution in the vessels unless the atrophic process has at any time been complicated by a pai)illitis. Processes which begin in the }iapilla itself, and involve the connective tissue, as they affect that portion of the nerve in which the central vessels ai'e situated, do cause constriction of these vessels, and thus give rise to a different ophthalmoscopic picture. A large proportion of cases of bilateral atrojdiy are certainly due to the same causes which give I'ise to degenerative changes in the sensory tracts of the s^jinal cord and brain. The ophthalmoscopic changes characteristic of atrophy are not met with where it is due to disease at one visual centre, and the defect in vision produced is of the hemianopic type. Any- thing like extensive degeneration in these cases only spreads downwards as far as the external geniculate body. It seems likely that when, as happens in a certain proportion, — probably quite ten per cent, of cases of general paralysis, — there is oi^tic atrophy, there is at the same time some spinal degeneration. Atrophy in disseminated sclerosis is most frequently accompanied by other paralysis of cranial nerves, e.g., of the sixth, seventh, etc. The eye sym^jtoms in connection with spinal lesions are often of importance from a diagnostic point of view, as showing the ATROPHY OF THE OPTIC NERVE. 273 eventually slow degenerative nature of the disease, even when, as sometimes happens at the time of first examination, the symptoms from the side of the cord are acute. Spinal as well as primary optic atrophy is a great deal more common in men than in women. Altogether, optic atrophy accounts for fully one-fourth of all cases of blindness. i8 CHAPTER IX. DISEASES OF THE IRIS AND CILIARY BODY. The Iris. Notwithstanding that a most iutimate anatomical connection exists between the different parts of the uveal tract (the iris, ciliary body, and choroid), it is more common to find inflamma- tion localised either throughout its whole course or, for some time at all events, to one particular portion of that tract, than to meet with a general uveitis. This is greatly owing no doubt to the differences which exist in the source from which the lilood supply for the various parts is immediately drawn. In this respect the iris and ciliary body are the most intimately connected, both l^eing su[)iilied by the anterior and posterior long ciliary arteries. The choroid, whose main function is to convey nutrition to the retina, is not only supi)lied from a different source, namely, the short posterior ciliary arteries, but is traversed by a network of vessels which are relatively richer in blood. The choroid, with its peculiar vascular supply, is mostly sub- ject to inflammation occurring in variously dis})osed and localised patches. The anterior portion of the uveal tract shows, on the other hand, a greater tendency to diffuse inflammation. The iris and ciliary body are frequently inflamed at the same time. This is almost invariably the case when the inflammation is first set up in the ciliary body. When originating in the ii'is, it is not uncommonly confined to it. Inflammation of the iris — iritis — may, from a clinical point of view, be looked upon as occurring under three forms — (1) plastic, (2) serous, (3) purulent. It may be 'primary^ or secondary to some general affection or dyscrasia. The most important forms, considered etiologieally, and jiretty much in the order of frequency in Avhicli they are usually met with, are — (1) rheumatic, (2) syphilitic, (3) HYPER.EMIA OF THE IRIS. 275 traumatic, (4) sympathetic, (5) gonorrhcual, and (6) tuber- culous, iritis. Hyperaemia of the iris. — Congestion of the vessels, which gives rise to some discoloration of the iris as a whole, and often at the same time to more or less contraction of the pupil (miosis), is a frequent accompaniment of irritation or infiamma- tiou elsewhere in the eye. It is met with, for instance, very frequently where foreign bodies, lodged in the cornea for some time, have produced a local irritation. It is also seen along with different forms of keratitis, with scleritis and inflammation of the deeper coats of the eye, and is, of course, also one of the first changes which take place Avhen the iris itself becomes either primarily or secondarily inflamed. The hypenemia gives a greenish coloration to blue and a dirty reddish appearance to dark irides. When miosis — what has been by Nettleship very appro- priately called congestive miosis — exists along with the hyper- aemia, the pupil should be kept dilated with atropine. Iritis. — Inflammation of the iris, from whatever cause, presents certain well-marked symptoms. When acute, there is always considerable />«?'« referred not only to the eye, but also, and in most cases indeed principally, to the surrounding jiarts — forehead, sides of the nose, etc. The pain is usually much less severe in the daytime — exacerbations coming on at night and during the early hours of the morning. In the serous and chronic forms of iritis thei"e is generally little or no pain. The pain of iritis is spontaneous, and accompanied by photo- phobia and lachrymation. It is often increased by light falling into the eye, and also by attempts at reading or using the eyes for any purpose requii'ing active accommodative effort — in short, by anything which produces, or tends to produce, changes in the shape of the pupil. Temperature, too, is not without influence. As a rule, the pain is increased by cold, whereas warmth has often a markedly soothing effect. There is always moi'e or less sensitiveness to touch. The course of an acute iritis is pretty definitely indicated by the amount of pain. As the inflammation subsides, the pain becomes less sefere, while greater pain at any time almost invariably co-exists with exacerbations of the inflammation. As a rule, too, the more acute the pain, the more severe is the inflammation. Another constant sign of iritis is a circumcoi'neal injection — that is, an injection of the fine network of deeper vessels which imme- diately surround the cornea. These vessels, the episcleral or 27G DLSEA8K8 OF 'J' III': JUiS AND CILIAKY BODY. .subconjunctival vessels, are branches of tlie anterior ciliary arteries and veins. They form a network' around the cornea, a (juarter of an inch or so in l)readth, the finest meshes of wliicli lie nearest to the cornea. According to the severity of the iritis, there are differences in the breadth of the ring of injection. Less severe cases are accompanied by injection of oidy a com- jtaratively narrow band, i.e., only the vessels inunediately sur- rciunding the cornea are distinctly visible as a pinkish zone. With increased intensity in the iritis this zone widens out, and in very severe cases may Ite associated with hyperiemia of the more superficial vessels of the ocular conjunctiva as well, or even in the most acute plastic forms, and in pmrulent iritis, with chemosis. When there is no irritation or focus of inflammation in the cornea, a circumcorneal injection is indicative of a deep- seated inflammation, so that its existence in such cases should at once direct attention to the iris. The breadth and intensity of the circumcorneal injection is, just as the amount of i)ain sufiered, a good measure of the severity of the iritis. With ordinary care it is impossible to mistake it for conjunctival hypenemia, but the possibility of the deep and superficial injections co-existing should be borne in mind, as in that case the difierential diagnosis presents rather more difficulty. It is seldom that any marked degree of swelling or redness of the eyelids occurs in iritis, except in the purulent form ; at most, there is usually only a little redness, confined to the margin of the upper lid. A third sign is hypercemia of the iris. The hypei'semia is often most distinctly visible in the region of the sphincter pupilke, i.e., in the zone almost immediately surrounding the 2)Upil, where some of the branches of the arteries in the iris form a ring. Sometimes, commonly enough in cases of traumatic iritis for instance, the engorged vessels give way, and lead to an effusion of blood into the anterior chamber (hyphtema). The inflamed iris is not only altered in colour, owing to hyperfemia, but the glistening ajjpearance which its surface presents in health is lost, while the markings on its surface, in so far at least as these can be seen with the naked eye, are more or less effaced. This muddiness of the iris is the result of exudation into the surrounding aqueous, as well as into its own tissues, and is therefore more or less complete according to the nature and amount of the exuded material. The parenchymatous exuda- tion leads to thickening of the iris. The thickening is usually not very great, and tolerably uniform throughout, although perhaps most marked near the pupil. Sometimes, however, it IRITIS. 277 forms })rominent masses })rojccting moi'e or less into the anterior chamber, and single or multiple. 8uch masses are mostly either tuberculous or syphilitic in their nature. The exudation, which does not infiltrate the tissues of the iris itself, passes into the posterior and anterior aqueous chambers, and leads to adhesions, more or less complete and firm, between the posterior surface of the pu})illary margin and the anterior capsule of the lens. These adhesions, or posterior synechice as they are called, form one of the chief and most serious compli- cations of iritis. They interfere with the mobility of the pupil, and render the result of subsequent attacks much more serious than they might be, as the pu[til may then be more or less occluded by exudation i)assing from one side to the other. The synechias which form in an ordinary case of iritis, where the inflammation has not been prolonged and severe, or the exuda- tion excessively plastic, are generally punctiform. That. is to say, there is not, as a rule, from one attack (and more especially if proper treatment has been adopted at an early stage), a con- tinuous attachment of the pupillary border to the lens capsule ; only isolated attachments here and there. These, too, are often most numerous at the lower part of the pupil, as the exudation which gives rise to them gravitates to the most dependent portion of the area over which the back of the iris is in contact with the lens capsule, and this is most often the lower part of the pupil. The synechiie are apt to form during the night, partly on account of the exudations which then take place, and partly, no doubt, owing to the iris then being more constantly at rest than during the day. The tacking down of the iris is not noticeable, as a rule, unless an attempt is made to dilate the pupil, when, instead of remaining round, it assumes an irregular shape, due to irregularity in the dilatation, which results from adhesions in some situations and not in others. Home days elapse before the synechia? become so firm as to resist any ordinary effort, such as may be made by a mydriatic, that is, a substance which has the power of causing dilatation of the pui)il. Fresh attachments yield in this way, usually leaving behind them some pigment from the back of the iris, so that it is not an uncommon thing to see, in an eye in which there has previously been iritis, a number of pigment spots on the surface of the capsule, indicating the posi- tions of the former attachments. In severe cases of iritis, or in cases where proper treatment has been neglected at the first, and in which there have been more or less frequent recurrences of inflammation at difl'erent 278 DISEASES OF THE TRTS AND CTTJAK^' BODY. lieriods, a coini)lete agglutiiiatioii between the iris and capsule takes ]»lace. Sometimes tliis may be so complete as to abolish altogether the space through which the aqueous humour which is exuded from the walls of the posterior chamber finds its way into the anterior chamber. This is called exclusion of the pupil. In the very worst cases, always com}>licated with cyclitis, the exudation is extremely jilastic and co])ious, and leads not only to agglutination of the pupillary margin, but to an attachment of the l)ack of the iris to the lens capsule, and to a practical obliteration of the posterior aqueous chamber. The exudation which ])asscs into the anterior chandler causes in many cases a mere cloudiness and discoloration of the aqueous Fig. 120. — Irregular dilatation of the pupil under atro caused by synechia. tpine, humour, more or less marked according to the amount existing at the time of examination, and generally denser at the most dependent part of the chamber. In the so-called serous iritis little deposits of lymph take jdace on the walls of the anterior chamber. In some cases of }>lastic iritis a spongy-looking fibrinous mass may be seen lying in the anterior chamber. In purulent iritis the pus secreted from the inflamed tissues collects in the anterior chamber, where it falls to the most de})endent part as hi^Mppon. The hypenumia of the iris, as well as the synechise, give rise to another sign of iritis, namely, a sliif/t/ishiiess in the movements of tlie pujyil. IRITIS. 279 In uncomplicated iritis the vision suffers at first only in so far as can be accounted for by the amount of obscuration in the ]tupil and aqueous humour in front of it. There is therefore frequently no great diminution of visual acuity. In cases where there is, the pupil is to a great extent occluded by lymph, or the iritis is complicated with choroiditis, or with cyclitis, along with effusion into the vitreous. Before referring any visual defect, found on examination, to the inflammatory changes in the eye, it is well to test whether vision is not improved with any glass. Owing to the inflammation, a previously latent degree of hyper- metropia may become manifest. It occasionally happens, too, that the lens is somewhat pushed forward, so as to give rise to a slight degree of myopia. Some increase in intraocular tension pi'obably always takes place in iritis. When there is not a very copious exudation, it is often, however, impossible to detect the increase ; in other cases, especially in serous iritis, it may be very marked indeed. At later stages of the disease, after the supervention of secondary changes, it is very common to find first an increase, and sub- sec|uently a diminution, of the tension within the eye. Very great differences are met with in the duration of an attack of iritis, as many cases, even such as eventually lead to the very worst consequences, so far as the functions of the eye are concerned, run a chronic and more or less painless course from the beginning. In some more acute cases, again, relapses may take i)lace, and thus the inflammation is protracted beyond its natural duration. Very much, indeed, depends on the treat- ment ado[)ted from the first. ]\Iost acute cases, if properly treated, last from three to six weeks. In some cases, where the iritis exists along with .some other affection, as for instance some cases of gonorrheal iritis, there is a tendency to the recurrence of the iritis every time that the symptoms with which it has previously been associated make their appearance. There is an inqiortant class of case in which the recurrence takes ])lace from time to time without there being any very marked association with other aftections. Such cases have re- ceived the name of recurrent iritis. Sometimes the recurrence takes place at regular intei'vals, most frequently at or about the same season, year after year. jSIore commonly there is no such regularity exhilnted in the periods of recurrence. When an annular adhesion has taken place, so that the pupil is completely blocked, further changes usually soon begin in the eye, owing to the liquid secreted from the ciliary processes not '280 DISEASES OK THK I HIS AND CILIAKY liODY. being al>lc to find its way forwards, and thus escape from the eye. The iris is then bulged forward, so that the anterior chamber is sliallowed, except at its centre. The appearance })resented by tliis condition is well called by French writers "iris bombe." The vision then no longer corresponds to the opacities in or in front of the pu})il, but is diminished by changes in the vitreous or choroid, or more frecpiently by those which the accompanying increased intra-ocular tension gives rise to. Eventually complete blindness from detachment of the retina, or secondary glaucoma, is the result if oi)erative interference has not been made in good time. Iritis is most common during the first three decades of life, and ])erhaps least common in infancy or early childhood. Fig. 121. — Iris bombe, witli cxndatioii on leus capsTile. Diar/nosis. — The iris is not only relatively fi-ecpiently inflamed, but serious harm is apt to re.sult if an iritis is allowed to take its own course or receives imjjrojjer ti'eatment. For these reasons the diagnosis is a matter of great practical importance. In all cases in which the white of the eye is congested, the very first c|uestion to be considered is as to whether or not this indicates the presence of either an already esta]:)lished or a threatened attack of inflammation of the iris. A careful examination, especi- ally of the distribution of the hyi)cnemic area, the transi)arency of the a(jueous humour, and the lustre or glossiness of the surface of the ii-is, should seldom fail to lead to a correct diagnosis in the IRITIS. 281 first stages of an iritis. Later on, the irregularity in the shajje of the pupil, or its immobility, and the greater or less defect of vision, render the diagnosis easy. It is, however, in the early stage that it is perhaps most important no mistake should be made. This stage, too, more frequently comes under the ob- servation of the family physician than of the ophthalmic surgeon. He will have in many cases to distinguish between the symptoms of a superficial inflammation and a deep, such as iritis ; and should he find the diagnosis ditticult, it will generally be better for his })atieut not to run the risk of delay, but to at once adopt a treatment by which the evil effects of iritis may be kept oS. A false alarm in this respect is preferaljle to a neglected opportunity. The only other condition, besides superficial inflammation of Fig. 122. — Iris bonibi' .shown in section. — After FucHS. the eye, with which there might possibly be a difficulty as to diff'erential diagnosis is glaucoma. It is important to bear this in mind, as glaucoma is also a condition for which neglect of proper treatment may do harm. In the congestive form it may present appearances not unlike those of iritis. The age of the patient, the previous history of " haloes " and obscurations, the condition of the field of vision, and, above all, the peculiar stippled and steamy appearance of the cornea, would ixjiut more or less definitely to glaucoma. One way in which the congestion of the white of the eye which is indicative of deep-seated inflammation differs from that associated with conjunctivitis only, is in its distribution. In both cases there may be more or less redness of the whole of the white of the eye, but whereas in conjunctivitis the redness diminishes in intensity from the periphery to the cornea, it is just the 2.S2 DISEASES OF THE IRIS AND CILIARY BODY. opposite with a deep congestion. More especially, then, when one sees a dense injection of tine vessels surrounding the cornea, must one's attention be directed towards the existence of deeper mischief. Of cour.se, in any such case the cornea itself would be carefully inspected, and, in the absence of any abnormality there, the cause of the circumcorneal injection looked for in the deeper structures of the eye. HyperaMuia of the iris itself causes, according to its degree and the original colour of the iris, more or less a]tpreciable change in that colour. Light irides .show slight changes in vascularity more readily than dark. Where there is any circumcorneal injection then in one eye only, a careful comparison of the two irides should be made, in a good light. Any ditference that there may be in respect to their colour, and due to congestion, is always most apparent in the areas immediately surrounding the pupil. As soon as the engorged vessels of the iris begin to transude, the serous surface loses its beautiful gloss and becomes dulled. A difference in this respect also should therefore always be looked for, where there is any reason to suspect inflammation of the iris. Pain is not always present in iritis, and therefore although it is, from the point of view of treatment, an important element to consider, it is of comparatively little value in diagnosis. Still, where with other appearances of iritis there were found to be localised spots of tenderness on pressure on the eye, and a history of .severe nocturnal exacerbations of spontaneous pain, these symptoms would be useful in further helping to establish or confirm the diagnosis. With proper care, then, there should usually 1)e little ditticulty in diagnosing iritis. The further diagnosis of the cause of the localised inflammation is often, however, by no means an easy matter. Fortunately the treatment is only to a certain extent influenced l»y the correct diagnosis of the cause. The treatment of iritis should vary to some extent according to the cause of the inflammation, and may therefore be con- sidered under the headings of Kpeclal and (jeneral treatment. The sjjecial treatment, applicable to the different forms of iritis, is referred to in connection with the discussion of each form. The general treatment, apjilicable to all cases, may be divided into that to l)o adoptetl at the time of the inflammation, and that which is necessary in order to avert the consecpiences of the com- plications to which it gives rise. What should be aimed at, at the time of the intianunation, is to put the eye as far as possible at rest, to prevent the formation of synechiie, and alleviate the pain. IRITIS. 283 An attempt is made to get the pxijyil thoroughly dilated with atropine, and this dilatation should be kept up as long as any circumcorneal injection lasts. Care should be taken in applying the atropine drops that they really get into the eye, and are not washed away by the copious ilow of tears met with in most cases. If a case of ii'itis be left to take its own course, or treated without the use of a mydriatic, it almost invariably happens that posterior synechice form. Sometimes, indeed, when there is much fibrinous exudation from the inflamed iris, some of it may become organised into a membrane stretching across and more or less completely occluding the pupil. The risk of this happen- ing is all the greater, owing to the tendency that there always is for the pupil to be contracted when the iris is inflamed. Synechias alone, though they do not cause any direct impair- ment of vision, are always an undesirable complication. They at least increase the risk that the eye runs from every subse- quent attack of iritis. The possibility of recurrence, too, should always be kept in mind. The view that recurrence is favoured by the presence of synechia? is, I think, hardly sufficiently prob- able to serve as a guide to treatment At all events, no attempt to detach such posterior synechite, when they are of .sufficiently old standing to have become regularly organised, should be made. The only thing that may be justifiable is to perform an iri- dectomy. If the case has first come under observation when the synechiai have begun to form, continued use of atropine may lead to their rupture, and a good dilatation may be got even after several days. In most cases, at all events, the unattached portion of the pupil dilates, and further mischief is to a great extent obviated. Whilst the supposed influence in causing recurrence which has been ascribed to synechias need not be considered, it does not follow that a more or less constant drag on these adhesions has never, under any cii'cumstances, an irritative eflect upon the iris. The conditions in this respect are undoubtedly quite ditterent when we compare the cases where there exists at the time an inflam- mation of the iris with those in which the iritis has long since subsided. It is a very common error to suppose that because it is in general desirable to use atropine or some other mydriatic during the whole course of an attack of iritis, it is always right to do so. In many instances the discontinuance of atropine is followed by a very rapid improvement. The reason of this is that as the main call for a mydriatic is to produce dilatation and thus prevent synechiie, the raison d'etre of such treatment 284 DLSKASE8 OF THE IllLS AND CILIARY 1U)DV. no longer exists wlien, liaviiig lieen licgun too late, the pupil cannot be pro})erly dilated l>y it. A dragging to no jmrpose on the already tirni synechije, with the iris inHanied, may do harm. It certainly tends to irritate and to keei) up the inflammation. As, too, the continuance of the inHammation means often the exudation of more and more plastic matter, the consequences may be more serious than if the patient were left without any treatment at all. A practical guide in this respect may be fornuilated as follows : — If the free use of the mydriatic (ajjplied, i.e., three or four times in the twenty-four hours) for three or four days in any case of iritis, seen or recognised only some time after it has begun, fails to cause any satisfactory dilatation of the pupil, it should be discontinued. Another practical point connected with the use of atropine in iritis, and one as to which the projier course to take is often a matter of no little difficulty, is the possibility of the treatment leading to increased intra-ocular tension. In elderly people especially, it is imi)ortant always to be on the lookout for this complication. Should it arise, the first thing to be done is to sto}) the atropine. If the tension is then soon restored to normal, it may be resumed before the pui)il has ])ecome quite small. It nuist then, however, lie used with caution, and not so free a dilatation aimed at. The best thing to do is to diminish both the frequency of the ai)plications and the strength of the mydriatic solution. A | per cent, solution of atropine, used once every second day, should be tried ; or homatropiue solution of the same strength may be substituted for the atro^nne. Where the glaucomatous sym})toms })ersist, or return with the use of even a weak mydriatic, a sclerotomy, done in the manner described at p. 384, is in some cases useful. The cases in which sclei'otomy may be resorted to are the cases of serous irido-cyclitis ; cases in which the inflammatory symptoms are less i^ronounced, and pain either not at all complained of, or, comparatively si)eaking, slight. In moi-e violent plastic iritis, any operation at the time of the infiannnation is contra-indicated. Mydriatics must be altogether given up, and surgical treatment deferred until after recovery. If anything then seems advisable, an iridectomy is generally to be preferred to sclerotomy. In addition to kee})ing the pupil dilated, whenever this is possible, it is important, in all cases of iritis, to keep the eyes Khaded from the light. This may either be done by darkening the room or by the use of dark glasses (neutral-tinted or. "smoked" glass, not blue). If the patient is able to be up, the latter method of subduing the light is preferable. He can IRITIS. 285 then occupy the same rooin.s as, and ejijoy the society of, other inmates of the house. Both eyes must be shaded. It is useless to cover the inflamed one with a handkerchief or bandage, as is often done, and leave the other one exposed to the untempered and constantly changing light of an ordinary room. During an attack of iritis, any use of the eyes for reading or sewing, or work of any kind calling for accommodation, must be prohibited. If there be any difhculty in enforcing this, it is a good plan to drop an occasional drop of atropine into the good eye, which, by paralysing the ciliary nuiscle, makes I'eading difficult or impossible without convex glasses, unless there is a sutticiently high degree of myopia. Even in myopic patients, although the acconunodative effort made is not nearly so great, it is better not to allow reading. In many cases, and particularly those of a rheumatic origin, the pain which accompanies inflammation of the iris is often so great as to call for special treatment. The pain may be more or less relieved by both local applications and drugs taken internally. It is particularly aggravated by light and by cold. Where it is intense, therefore, it is best to keep the patient in semi-darkness and in bed in a room in which the tem})erature is kept equable, and protection made against draughts. Generally, the pain is most severe during the night, especially from midnight to four or five o'clock in the morning. Leeching (either with the natural or artificial leech) used to be a very common treatment for painful iritis. No doubt leeches applied to the temple have often a very marked effect in dispelling the pain. Their effect is, however, only temporary, and is rarely su})erior to less troublesome means of producing relief. They do not influence in any way the course of the inflammation. In my own practice I have long since given up leeching, and rely entirely u})on the application of heat. Hot fomentations may be used for a c|uarter of an hour at a time, every two hours or oftener, at the times when the pain is most severe. After using the fomentations, the eye may be covered with a pad of cotton- wool, retained by a loose bandage. Cocaine alone or combined with adrenalin dropped into the eye immediately before foment- ing sometimes helps, but it should only be used in cases where the pupil has dilated well under atropine. Of drugs, antipyrin or phenacetin in 10-gr. doses, and salicin, are the most generally useful. In many cases salicin has the effect of rapidly relieving the pain. It should be used from the beginning, being given in 7- or 8-gr. doses every hour for ten or twelve hours, or until toxic effects are manifested; then thrice daily in 10- or 15-gr, doses. 286 DISEASES OF THE IRTS AND CILIARY BODY. The treatiiient sometimes recjviired for cases of old iritis is iridectomy. This operation is called for in two diliereut classes of cases. In the first i)lace, to improve vision where tlie pupil is small, and to a great extent occluded, though the condition has not led to serious nutritive changes; and in the second place, with the object, as well, of preventing the complete destruction of vision wliich either the existing condition or the danger of recurrence of the inflammation has threatened. Iridectomy, when iterformed for iritis, should be done at a time when all symptoms of inflammation have subsided, and the portion of iris excised should be large, so that in the event of a subsequent attack taking place, the coloboma, or artificial pui)il, may be less likely to close up. At the same time, a large iridectomy gives the best chance for the i-e-establishment of the normal flow of aqueous from the site of its exudation to that by which it leaves the eye, the interruption in which process may have such serious consequences. Iridectomy is urgently called for, and often followed by the most brilliant results, w'here there is an "iris bombe " and increased intra-ocular tension. Even in cases where the tension is below normal, if there be not already blindness, iridectomy may prove of service. In recurrent iritis, too, an iridectomy, performed at a time when the intiammation has subsided, often prevents the recurrence or lessens the frequency and severity of subsequent attacks. Fortunately, when sj-nechiiv are ruptured during the excision of a piece of iris in this opera- tion, it is extremely rare to find that their attachment to the lens capsule is sufficiently firm to lead to any laceration of that membrane. Practically speaking, this never occurs. If it did, the risk of iridectomy causing cataract would be very much greater than it actually is, and the great benefits which are derived from surgical interference in cases of neglected iritis would be seriously curtailed. Other operations which are performed for old iritis, such as attempts at separating the synechia;, and sclerotomy, are either less safe or less efficient than iridectomy, and on that account not to be recommended. In the worst cases, where the iris has become friable or "rotten," and more or less atrophied from repeated intiammation, and where the attachments to the capsule are very extensive owing to the association with cyclitis, it is sometimes possible to improve vision and prevent further destruction taking place by removing the lens. An operation of this nature is most frequently called for in cases of severe sympathetic iritis. When iritis is not set up by injury, the two most common causes are rheumatism and syphilis. RHEUMATIC IRITIS. 287 Rheumatic iritis. — This foi-m of iritis occurs most frequently during the i)rinie of life, between the ages of 20 and 50. There is often a distinct history of former rheumatic affections else- where, or there may be other })arts affected with rheumatic inflammation at the same time. At other times there is no other rheumatic manifestation, and yet a great tendency shown to iritis from exposure to cold. Most frequently only one eye is affected, but both may be, either at the same time or within a short interval. The inflammation occurs with very varying degrees of severity, and the prognosis, even in the most severe cases, is favourable if proper treatment be adopted from the first, before extensive synechite have formed or cyclitis has become developed. The treatment consists in avoiding changes of temperature or light and the use of the eyes, also in keeping up the dilatation of the pupil — in attention, in fact, to the general line of treatment for iritis. Besides this, great benefit is usually got from the use of salicin or salicylate of soda. Perhaps the best way of using salicin is for the patient to begin taking 7 to 8 grs. every hour, remaining in bed all the time, and afterwards to take from 10 to 15 grs. thrice daily for some time. In this way it is some- times possible to cut short the attacks, and in almost all cases the pain is lessened. In obstinate recurrent cases it is well to avoid too much care in preventing draughts, etc., as the suscepti- bility of the patient may thereby be considerably increased. It is better to make some systematic attempts at a gradual harden- ing, and allow more and more exposure to the conditions which appear to bring about the attacks. At the same time, two or three visits to Wiesbaden often do good. The baths, not the waters, should be taken, and should not be begun until a few weeks at anyrate have elapsed since the last attack of inflamma- tion. In the distinctly rheumatic, other baths, such as Harro- gate, Bath, Droitwich, Nauheim, Wildbad, Acqui, etc., may be recommended. G-onorrhoeal iritis. — Closely allied to rheumatic iritis is the rare form which is associated with gonorrhoea. The inflamma- tion is always severe. It always occurs in both eyes, though not always quite simultaneously, and with, it may be, ditterent degrees of severity in the two eyes. Successive attacks of gonorrhoea are sometimes accompanied each time by iritis, and in other cases, although no fresh inoculation takes place, a return of the joint aftections may be accompanied by a recurrence of the iritis as well. The local treatment is the same as for other forms of iritis. 288 DISEASES OF THE TIUS AXD CMLIAllY BODY. Iodide of |)otas.siiiin in large doses seems to l»c the best general treatment at tirst, followed, as the inHammation sultsidet;, by (luiiiiiic and iron. Syphilitic iritis. — Iritis occurs as a secondary manifestation of acquired syphilis, and also in irdicrited syphilis. Iritis is for the most part a late secondary manifestation, making its ap[)ear- ance as the others are fading away, or after they have altogether disappeared. Sometimes, however, it runs its course contem- poraneously with other secondary symptoms, and may even be the tirst to ai)i)ear. The hereditary cases of iritis mostly occur at about the time ■^Jtiw^^ Fig. 123. — Case of gumniatou.s iritis, showing characteristic swelliug at lower border of piipih Pupil has dilated irregularly owing to synechia, aud there is a trace of hypopyon. of puberty, and in association with interstitial keratitis. Some few cases are met with in early infancy, or still more rarely in intra-uterine life. It is as a rule difficult, or impossible, to detect from the mere inspection of the eye alone when the iritis is due to syphilis. One has therefore generally to be guided by the pre- sence or absence of other secondary symi)toms in arriving at a diagnosis, or by the history in cases where the iritis exists alone. In some cases the intiammatory changes in the iris, which are usually of a plastic nature, bear strong evidence of their syphilitic SYPHILITIC IRITIS. 289 origin. Thus the development of more or less prominent yellowish vascularised nodules in the iris, or of localised tume- factions of the iris tissue, a condition known as gummatous iritis (see Fig. 123), is almost invariably due to syphilis. The gummata grow slowly, often causing very little pain or other evidence of inflammation until they have attained some size. Their vas- cularity increases as they grow, so that while at first they appear as yellowish spots, they later on change their colour to a dirty brown. It is this alteration in colour which in doubtful cases mainly distinguishes them from tubercles. The latter, too, are as a rule more numerous, and mostly spring from the peripheral part of the iris in the region of the angle of the anterior chamber, whereas the gummata show a greater preference to develop in the paren- chyma surrounding the pupil. The gummata may undergo fatty degeneration and become absorbed, leaving no trace, or only a slightly depressed atrophic spot at the sites where they existed. In other cases they increase in size, growing into the anterior chamber, and lead, with or without perforation of the cornea, to shrinking of the eye — jjhildsis hulhi. The latter result is more uncommon than the former, and most likely to occur where the gummata originate in the peripheral portions of the iris, when they are frequently associated with the forma- tion of similar nodules in the ciliary body. Gummatous iritis does not, as the name might imply, belong as a rule to the tertiary period of syphilis, but to the secondary, although on the whole appearing rather later than the more common form. Syphilitic iritis may occur in one or both eyes. No local cause can, as a rule, be given for its occurrence — there has been no trauma, no exposure to cold, etc. In the treatment of syphilitic iritis it is well to begin mercury at once. Of the different ways of giving mercury, I have person- ally had most experience of inunction. The mercurial ointment should be rubbed well into the skin of the axillfe or inner side of the thigh for fifteen to twenty minutes once daily, and this continued for at least a month. A daily painting of the gums with a little tincture of myrrh, and frequent brushing of the teeth (not less than four times daily) with Condy's fluid, will almost invariably keep away any complication with .stomatitis. But, of course, patients have to be carefully watched during this treatment, more especially as they have frequently already under- gone mercurial treatment, before the onset of the iris inflamma- tion. What I have seen, at the hands of French surgeons, of intra-muscular injections of the biniodide in syphilitic eye 19 290 DISEASES OF THE IRIS AND CILIARY I'.ODY. iittectifjiis gonerally, lia.s led me to regard that method as a suffi- ciently efficient way of using mercury.' I have, however, no personal experience of it, nor do I believe that, although more cleanly and perhaps less troublesome, it is in all respects quite as satisfactory as inunction. I should, however, certainly give it the preference over either internal administration or subcutaneous injection. Subconjunctival injection, so far as my experience goes, is also not to be recommended, at all events in iritis. One practical i)oint of some importance, as it necessarily in- fluences the treatment which one adopts, is the question as to the diagnosis of syphilitic iritis. Owing to the frequency of rheu- FlG. 124. — Case of gummatous iritis, showing immerous confluent swellings occupying the circiimpupillary area of the iris, also a few spots of fibrinous exudation at the back of the cornea (descemititis). matic iritis, and to the possibility of the resisting power of a syphilitic individual being no doubt more or less reduced, one may often have to ask one's self whether the mere fact of an individual who has at one time acquired syphilis, having an inflammation of the iris, is sufficient to justify the diagnosis of syphilitic iritis 1 There certainly seems to me to be too great a tendency in many quarters to ascribe an iritis to direct syphilitic causation wherever there is a syphilitic history, or even a reasonable suspicion of such a history. Iritis occurring under other conditions in syphilitic individuals — for instance, a year or more after the primary symptoms, and SEROUS IRITIS. 291 then it may be in one eye alone — .should not be looked upon as so essentially syphilitic as to call for mercurial treatment. Accord- ing to the patient's general condition or diathesis in other respects, salicin, iodide of potassium, or iron and quinine, are more suitable drugs to use, in addition to the necessary local treatment. It is well, too, always to remember that iritis is really an unusual complication in syijhilis. The various statistics give proportions varying between 1 and 4 per cent, of all cases of syj^hilis. Inasmuch, too, as in many of the statistics no very critical distinction is made into secondary syphilitic iritis and iritis simi)ly occurring in those who have been the subjects of acquired syphilis, the lower figure appears to me to more correctly express the actual proportion all round than the higher. The forms of iritis already described, along with sympathetic iritis, which is discussed in the chapter on Sympathetic Ophthal- mitis, are the main forms of the plastic variety. The association of plastic iritis with severe corneal inflammations, owing to the irritation of toxins formed in the inflamed area, has already been referred to. Serous iritis. — This variety of iritis, which receives its name on account of the exudation being on the whole more serous than fibrinous, is almost invariably associated with a cyclitis or choroiditis. It is, therefore, properly speaking an irido-cyclitis. It is much more frequent in women than in men. According to Horner the proportion in the two sexes is as ten to three. Cor- responding to the comparative absence of a plastic exudation, serous iritis is a less painful, more insidious, and usually more chronic affection than most of the forms of plastic iritis. The irritation it produces is indeed often so slight, that the attention of the patient is first called to the eye by the certain degree of haziness of vision to which it gives rise. The back of the cornea is then found, on examination, to be covered, mainly in its lower C[uadrant, by a number of minute brownish specks, while the aqueous humour is at the same time more or less turbid. The circumcorneal injection is usually slight and most marked at the lower part, with a great tendency, however, to become more apparent if the eye be kept open for some time, or if it be rubbed. The small deposits which lie on the membrane of Descemet, consist mainly of pigment, along with leucocytes and fibrin. This condition often receives the name of keratitis punctata, although it is not, properly speaking, a keratitis. Descemetitis is another term applied to the same appearance (see Fig. 125). The pigment evidently comes from cells, and is not altered 292 DISEASES OF THE IKTS AND CILIARY BODY. blood pigment. The larger spots are clue .sometimes, it would appear, to proliferation as well of the underlying cells of Desceniet's membrane. In the first stage of the inflammation there are no synechiai, or only very trifling ones. Often a very distinct hyperajmia of the pai)illa is to be made out with the oi)hthalmoscope. In the majority of cases synechia? begin to form after the inflamma- tion has continued for some weeks. At the same time the hypcnemia of the papilla becomes more marked, and difluse white floating opacities make their appearance in the vitreous. These changes are accompanied by alterations in the intra-ocular Fig. 125. — Case of seroiis irido-cyclitis, showing deposits at back of coi'uea arranged in characteristic trianguhar form. tension, which is first increased, and afterwards very often con- siderably diminished. The prognosis in this form of iritis depends much on the general health of the patient, as well as, of course, on the extent to which the uveal tract as a whole has particijiated, and on the completeness of the synechite. A number of cases end in com- ])lete recovery, but more frequently the recovery is incomplete. In some cases only slight changes in the vitreous occur at all, so that recovery takes place after the inflammation has remained for some time in the first stage, the symptoms being mainly confined to the anterior portions of the eye. In others, again, SEROUS IRITIS. 293 the more or less dense vitreous opacities clear away after longer or shorter periods, and no further harm results, if the formation of synechise has been obviated by keeping the pupil dilated. Owing however, no doubt, to the alterations which the uveal inflammation brings about in the nutrition of the eye, there is a tendency, in cases where opacities of the vitreous have been marked and persistent, towards the gradual development of cataract, usually posterior polar cataract. The worst cases are those in which extensive synechias have formed, with occlusion of the pupil, and the termination, as in other forms of iritis, either in secondary glaucoma, or detachment of the retina, with shrink- ing of the eye. The etiology of serous ii"ido-cyclitis is not always very clear. The preponderance of cases in women, already referred to, shows that syphilis cannot be, at all events, a general cause. Probably Horner's view is the correct one, that it results from some patho- logical condition of the blood or blood vessels. He points out, for instance, that it is this variety of iritis which is apt to occur after fevers or severe illnesses. Often there are menstrual dis- turbances, or actual disorders of the sexual organs, in women affected with this disease ; all are more or less anaemic or chlorotic. When it occurs in men, they are for the most part, ill-nourished and anaemic. In the treatment greater care must be taken than in the case of the plastic variety of iritis not to use atropine too freely, on account of the tendency there is towards increased tension. The pupil should at first be kept dilated, or semi-dilated, with as weak a mydriatic as possible. When the deposits at the back of Descemet's membrane are numerous and large, it is well to perform paracentesis of the cornea, taking care not to allow the aqueous humour to escape too rapidly. The tapping of the anterior chamber may be frequently repeated if undertaken with proper antiseptic precautions. It appears to have a beneficial influence on the inflammation, and to favour the absorption and disappearance of the exudation into the vitreous as well. When these vitreous opacities are dense, wet packing and subcutaneous injections of pilocarpine are often of use in promoting absorption. Where there is marked increased tension, especially in elderly people, I have found sclerotomy performed with the triangular- shaped knife (keratome) of great use. The absence of pain, or of any tendency to aggravation from cold, render it unnecessary to take particular precautions to keep the patient's surroundings at an equable temperature. Indeed, in most cases open air and moderate exercise is desirable, especially in summer. Proper 294 DISEASES OF THE IllIS AND CILIAllY BODY. regulation of the action of the bowels should never be neglected, and iron in some form given. I have found the natural iron waters, such a.s Flitwick or Levico, useful, and in summer pre- scribe these to be drunk slowly outside before breakfast, and in the afternoon, in all cases where the conditions render this jKDssible. Five-gr. doses of chloride of calcium may in some cases be followed by rajtid improvement. Turkish baths are also useful. After fevers, iron and quinine, and a generous diet, with regular intervals of rest, are indicated. Traumatic iritis. — Furulent iritis. — Iritis may be set up by direct injury to the iris, or by injury to the contiguous parts of the eye — the cornea, lens, or ciliary body. The injury may be an accidental one, or be caused by some operation, such as the extraction or discission of a cataract. The severity of the inflammation depends greatly upon whether or not septic matter or any foreign body has remained in the eye. These almost invariably give rise to a purulent inflammation. The pus which is then excreted from the inflamed iris not only infiltrates its tissues, collecting mainly between the endothelial covering and the stroma, but also falls to the bottom of the anterior chamber as hypopyon. At the same time some of the vessels give way, causing haemorrhage into the iris. Purulent iritis may, too, form only a part of a general sup- purative destruction of the eye, the result either of external local changes, or of septic emboli in the choroid. Sometimes a traumatic iritis does not occur at all, or only slightly, at the time of an injury, but is set up at some subsequent period by changes which occur in the eye, and lead to persistent dragging on, or irritation of, the iris. The treatment of traumatic iritis will depend greatly upon the nature of the injury as well as upon the severity of the inflam- mation. If the lens has been wounded, or if a foreign body be lodged in the iris or in the anterior or posterior aqueous chamber, some o})erative interference will usiially be called for. Whei'e there is no foreign body, but where the nature of the accident and the presence of much hy[)opyon render the septic character of the inflammation undoubted I have found the subconjunc- tival injection of fully saturated, freshly [)reiiared chlorine water the most satisfactory treatment. In a numlier of cases improve- ment begins then at once, with the rapid disappearance of the hypopyon, and is generally continuous. Only comparatively rarely does the injection have to be repeated when a good result has followed the first injection of 15 to 20 droi>s in two or three diflereut places round the cornea. TUBERCULOUS IRITIS. 295 Tuberculous iritis. — This is a rare form of iritis, though pro- l)ably more frequent than used to be supjiosed, which may occur in one or both eyes, and most commonly makes its appearance before the period of full growth. The inflammation begins as an ordinary serous or plastic iritis, and is often preceded by ill-health and loss of fiesh, and accompanied by, sometimes very considerable, swelling of the surrounding lymphatic glands. Tubercles in the shape of small yellowish nodules, usually in considerable numbers, make their aijpearance, and the iritis shows a tendency to become chronic. The tubercles may become Fig. 126. — Case ot tuljeiculouM mass in iris and anterior chamber (granuloma iritlis). confluent, or disappear and be replaced from time to time by others. Tuberculous disease may or may not exist in other organs at the same time. Some cases completely recover ; others, again, lead to shrinking of the eye, or to perforation and protrusion of a tuberculous mass externally. There is seldom any difficulty in the diagnosis. Gummata of the iris, w^hich they somewhat resemble, are more vascularised, and occur, besides, at a different time of life. In the treatment, the possibility of the disease in the iris acting as a source for self-infection must always be kept in view. 296 DISEASES OF THE IRIS AND CILIARY BODY. This clanger is api)arently greatest in the cases of granuloma which lead to ])erforation, Vtut it is also present in the form which ends in phthisis of the globe. There can be no doubt, therefore, that the proper treatment in the worst cases is enu- cleation. In some cases an isolated tuberculous mass may be excised (along with the portion of iris in which it is situated), but this treatment is only rarely successful. The iritis must be treated on the ordinary lines, and the patient's strength kept up by nourishing food, and the exhibition of anti-strumous remedies. Cyclitis. — Inflammation of the ciliary body, or cyclitis, is l>est considered in this connection, as it is so frequently associated with iritis. This association is ^Drobable in all cases in which there are deposits in the posterior surface of the cornea. It is certain where there are changes in intra-ocular tension, whether that be increased or diminished. Often in cyclitis there is a very marked diminution in tension. Cyclitis is also cer- tainly present along with iritis when the degree of visual dis- turbance is greater than can be accounted for by the visible changes in the pupil and anterior chamber. The character of the exudation from the inflamed ciliary body may, as in the case of iritis, be mainly serous, or it may be plastic or purulent, and the symptoms may differ more or less accordingly. The exudation passes from the two free surfaces of the ciliary body into the posterior aqueous chamber and into the vitreous chamber. A constant symptom of cyclitis is therefore more or less in- transparency of the vitreous. Often this can only be inferred from the defect of vision which it produces, as, owing to the presence of synechias, and the difficulty of obtaining dilatation of the pupil, the objective determination of the opacities may be a matter of difficulty. The exudation from the anterior portion of the ciliary body leads to synechise, preciiMtations on Descemet's membrane, obliteration of the pupil, and, in bad cases, to an agglutination between the posterior surface of the iris and the capsule of the lens. In the case of purulent cyclitis there is also hypopyon. That portion of the exudation of plastic or purulent matter which passes through the ciliary processes into the vitreous chamber may remain confined to the immediately surrounding regions, or may permeate the vitreous more or less extensively, causing it to become more liijuid. If absorption does not rapidly take place, changes occur in the exuded matter leading to the formation of filamentous or even membranous shreds of a CYCLITIS. 297 low form of connective tissue. Where there has been an ex- cessive exudation, the subsequent shrinking and liquefaction which takes place may result in detachment of the retina, and consequent complete loss of vision. In many cases, where the exudation has accumulated at the anterior portion of the vitreous, subsequent contraction, taking place during its organ- isation, leads to displacement of the lens. Most frequently this displacement is forward, so that the anterior chamber becomes more or less shallowed ; sometimes, owing to the contraction being more in one direction than in others, some portion of the lens is tilted forward, and the chamber is shallowed in one direction and deepened in the opposite. In some old-standing cases the anterior chamber is deepened, so that a funnel-shaped depression is observed to exist at its centre. This is produced by contraction in an antero-posterior direction, which brings about an approximation of the lens and the optic papilla, to which the organised exudation has formed an adhesion. In such cases there is at the same time diminution in the intra-ocular tension. Cyclitis may be set up traumatically, or by some alteration taking place within the eye. A severe blow on the eye may be sufficient, but more common causes are penetrating wounds, and the introduction of foreign bodies either into the ciliary body itself, or into some of the surrounding parts. In some cases where foreign bodies have become encapsuled, they may become suddenly dislodged, and then set up cyclitis months or years after the accident which drove them into the eye. It may be that, having lodged in the lens, thus producing traumatic cataract, the gradual disintegration and absorption of the lens leads to an alteration in the position occupied by the foreign body. The new position is apt to be one which causes more irritation of the tissues of the eye and cyclitis. Traumatic cataract alone, i.e. without the presence of any foreign body, may in various ways set up cyclitis. This may happen if a rapid swelling takes place where the lesion in the capsule has been small, and the swollen lens matter does not readily make its escape into the aqueous chamber. Again, it may happen if the iris, owing to its having formed adhesions to the wound in the capsule, is subjected to more or less constant dragging. A dislocated lens is also very apt to set up cyclitis, more especially if it has at the same time undergone advanced degenerative changes. While irregular and septic Avounds in the ciliary region almost invariably lead to an immediate and usually purulent cyclitis. 298 DISEASES OF THE IRIS AND CILIARY BODY. very littlo irritatioia may result from clean and ase})tic Avounds in the same situation. Wounds of the ciliary region should be carefully washed with some antiseptic lotion, and any separation of the lips as much as possible prevented by cutting oft' or replacing the intervening structures. Swollen lens matter, when causing irritation, must be removed in the manner described at }). 208. A dislocated lens must be extracted, and where any dragging on the iris has set up irritation, or appears likely to do so, it will be necessary to perform iridectomy in such a position as to free if possible the portion dragged upon. When cyclitis is once set up, the treatment should consist in keeping the pupil dilated with atropine, in applying hot fomenta- tions to the eyes, and in leeching over the temples. The eyes should be shaded, and the patient not allowed to read, or to use his eyes for any near Avork. In purulent cases it is well to ai)ply a pretty tight bandage over the affected eye, as this seems to aid in checking the tendency to pano})hthalmitis — that is, to an extension of the purulent iniiammation to the choroid. Tumours of the iris. — Both simple and malignant tumours are met with in the iris. They ai'e rare, and not of particular interest. Two kinds of cyst occur — the epidermuid and the serous. The former only appears to come after there has been some penetrating wound of the cornea, and the latter is usually also of traumatic origin. The proportion of traumatic cases is at least four in five. At the time of the accident some small portion of skin or corneal ei)itlielium, or a piece of an eye- lash, is driven into the anterior chamber, and there proli- ferates, assuming usually a cystoid type of growth. The time elapsing between the accident and the formation of an epider- moid cyst is at least two months, and may amount to several years. The serous cyst seems mostly to extend from the margin of the anterior chamber. It is, in fact, a kind of cystoid degenera- tion of the iris, leading to the formation of a diverticulum at the angle of the chamber. The prognosis, is bad in both these forms of cyst, as they are apt to go on growing, and eventually lead to destruction of the eye. The treatment consists in excising them as soon as possible, along with the portion of iris to which they are attached. Care should be taken not to rupture the cyst wall during removal. But it is by no means always possible to avoid this. ALTERATIONS IN THE IRIS BY INJURY. 299 Like other parts of the eye, the anterior chamljer may be visited by a cysticercus. In the cases which have been observed, and which have occurred almost exchisively in Germany, the surrounding cyst has sometimes been clear, at other times purulent. Sarcoma of the iris is usually but not always an extension from the ciliary body, which is a common site for malignant tumours within the eye. It may be pigmented (melanotic) or not. Only in the latter case is there any possibility of mistaking it for a gummatous or tuberculous mass. Its early diagnosis is a matter of importance. Alterations in the iris produced by injury. — Lacerations of the iris may be produced by penetrating wounds. When the Fig. 127. — Cyst of the iris after injury. history of the accident points to the impaction of a small body, the appearance of the laceration of the iris is strongly suggestive of its presence somewhere in the eye. Sometimes the laceration has taken place at the pupillary margin, — more frequently, how- ever, it is elsewhere ; and the more peri[)heral it is, the more importance does it acquire from a diagnostic point of view, when the question arises as to whether or not a foreign body is lodged in the eye. With the more central wounds there may usually be made out the corresponding wound in the lens ; while in the case of peripheral wounds of the iris, a trauma of the lens is neither of so frequent occurrence, nor so easy of observation when it has occurred. The laceration may cause bleeding. 300 DISEASES OF THE TUTS AND CILIARY BODY. which is usually slight, and rapidly absorbed. Synechite almost always occur in cases where the wound is situated not far from the itujjil, unless the pujiil has been well dilated soon after the accident. A simple wound of the iris is not likely to cause iritis, but when, as so often happens, the lens is wounded at the same time, or a foreign body is lodged in the eye, the chances of inflamma- tion being set uj) in the iris are very great. The treatment, too, will vary according to the severity of the accident. When the iris alone is injured, a few days' dilatation of the pupil with a mydriatic and rest to the eyes is all that is usually required. Various injuries to the iris are produced by blows on the eye ; the simplest of these, though not the most frequent, is a rupture of the sphincter muscle. Sometimes a rupture takes place in the direction of the radial fibres of the iris, but without involving the sphincter. This, too, may occur spontaneously in cases where the iris is atrophic, and dragged on in some particular direction. A more common accident, produced by severe contusions, and often associated with rupture of the choroid, is a separation of more or less of the iris from its peripheral or ciliary attachment. This accident (see Fig. 128), to which the name of irido-dialysis is given, is always accompanied at the time by hyplijema. It may occasion uniocular diplopia, if the eye, from an error of refraction or owing to the state of accommodation, is not focussed for the object looked at. The separation causes a flattening of the corresponding portion of the pupillary margin. All degrees of irido-dialysis are met with. When very slight, it can only be easily diagnosed by reflecting light into the eye, when the red colour of the fundus can be seen at the periphery of the iris, as well as through the pupil. A spontaneous re- attachment of the iris to the ciliary body practically never occurs. Occasionally, in performing iridectomy, if the iris is too forcibly drawn upon by the forceps, a separation occurs at its perii)hery. Another and very curious result of blows on the eye is the complete or partial retroversion of the iris. This gives rise to the appearance of a conq)lete absence of any iris at the position of the lesion. When [>artial, it is usually possible to see the folding of the iris, where the inverted portion joins on either side the portions which remain in situ. The existence of the folded-back portion can also be inferred from the fact that the ciliary processes are not visible with the ophthalmoscope, not- ALTERATIONS IN THE IRIS BY INJURY. 301 withstanding that no iris intervenes between the cornea and the margin of the lens. Temporary or permanent dilatation of the 2ni2nl may also result from a blow on the eye. Often the dilatation is irregular. Where the lens is dislocated or absent, and thus the natural support which the iris gets by its apposition to the capsule in the normal state is interfered with, or altogether lost, the iris is observed to shake with the movements of the eye. This tremu- lous condition of the iris is called irido-donesis. It should direct attention to the lens, an abnormality in which is the most Fig. 128. — Case showing separation of iris from its peripheral margin (irido-dialysis), caused by a blow which was also followed by cataract. common cause, though sometimes a not inconsiderable degree of shaking may occur in cases where, from some cause or other, the posterior aqueous chamber is unusually deep. In old cases of iritis, especially if complicated by any condi- tion which gives rise to constant dragging on the iris, atrophy of the iris takes place. The tissues may be so thin as to admit of more or less light passing through from the fundus on oph- thalmoscopic examination ; often there are actual rents here and there. Atrophy of the iris is common in the last or degenerative stages of glaucoma. :)0-2 DISEASES OF THE TPJS AND CILIAKY IJODY. Congenital anomalies of the iris. — Colohonm of the iris (sec Fig. 1"J'.)) is a congriiital defect, which is due to non-closure of the fuetal li.ssure. It may or may not be associated with a similar congenital defect in the choroid. The coloboma may be of all sizes, up to one-fourtli of the whole iris. It always occurs downwards, or downwards and inwards, and generally, though often not to the same extent, in both eyes. It may be either total or partial — that is to say, it may extend right up to the ciliary body, or close before reaching so far back, or may even be bridged. Closely allied often to coloboma of the iris is the condition known as correctopia, or eccentric displacement of the pupil. Owing to faulty development of the muscular fibres of some portion of the iris and ciliary body, the pupil becomes 'drawn Fig. 129. — Congenital coloboma of the iris (inwards and downwards). up, from the preponderance of action of the more complete portions. Aniridia. — Not so common as coloboma, but still not of very rare occurrence, is a congenital absence of the iris — aniridia, or irideremia. This condition is most commonly met with in several members of the same family, and is inherited. It almost in- variably occurs in both eyes. The appearance which the total absence of the irides gives to the eyes is peculiar, and not alto- gether like that which most resembles it, namely, maximal dilatation of the pupils. In all cases which have come under my own observation there has been at the same time a ring of pigmentation in, or immediately behind, the peripheral portion of the cornea. In many cases there is some defect in the lenti- cular system, — either congenital displacement of the lens, due to CONGENITAL ANOMALIES OF THE IRLS. 303 some faulty development of the suspensory ligament, or more or less opacity. Myopia, or defective accommodation, are frequent concomitants, and there is usually as well more or less defect of sight. Patients with, this defect are bothered by dazzling, and acquire the habit of screwing up their eyes. There is often at the same time photophobia, and, in the cases where the associated defects are most marked, nystagmus. Albinism. — The general absence or defective development of pigment throughout the body, which characterises the albino, gives to the iris a very peculiar appearance. It has usually a pinkish or faint lavender colour, and the details of its structure are more evident than in an iris in which there is a normal ^%1SK^^ Fig. 130. — Congenital coloboma of the iris. amount of pigment present. When the eye is examined with the ophthalmoscope, a considerable amount of light, reflected from the fundus, is found to pass through the iris, and it is this translucency, as well no doubt as the associated absence of pig- ment in the choroid, which gives rise to the dazzling from which albinos suffer, and which causes them constantly to screw up their eyes. The vision is more or less imperfect, and there is some degree of nystagmus in all cases. Some cases are met w^th where the pigment is not altogether absent. In these there seems, as a rule, to have been a gradual development of pigment since birth, with a corresponding improvement of vision. Albinism is sometimes met with in several members of the same family. 304 DISEASES OF THE TUTS AXD CTLTATn' P.ODY. Little can, a8 a rule, be done to improve the sight. Some find comfort, without any visual imi)roVement, by the use of darkened glasses. Stenopaic apertures are only useful in cases where the nystagmus is slight. The iris of the new-born infant is grey or blue in colour, and either remains so, or gradually accumulates pigment, so as eventually to become more or less brown. These changes take place, as a rule, very early in life, but are sometimes deferred till the third or fourth year, or even later. The influence of heredity on the colour of the eyes is very marked, and there seems no greater tendency to inherit from either parent. It has been found, for instance, that of the off- spring of parents with differently coloured irides — that is, the '^'^«%Pnntsm^;/' '^Nrwt^^^'*^'^ Fig, 131.— Double congenital eoloboma witli displacement of the right pupil (correctopia). irides of the one parent dark and of the other light — 50 per cent, have dark and 50 per cent, have light irides ; while when both parents have light or dark irides, 96 per cent, of the offspring present the same colour as the parents, and only 4 per cent. not. Of these 4 per cent., most have both eyes the same, inheriting probably from some more remote ancestor ; while a few present the appearance known as heterochromia^ where the one iris is brown and the other blue. In normal eyes the pupillary membrane, which, during the greater part of intra-uterine life, stretches across the pupil, only remains persistent in that part which covers the iris, whose endothelial layer it becomes. It is not a very uncommon thing to find, however, small portions of the membrane stretching across the pupil in the shape of one or more fine threads. To CONGENITAL ANOMALIES OF THE IRIS. 305 this condition the term 2^e):sistent 2nqnllary memhrane is applied. Occasionally a considerable portion of the membrane persists, and is adherent to the capsule of the lens, usually at the same time having filamentous attachments to the iris. This mem- branous form produces considerable defect of vision, Avhile the more common filamentous form is of no importance whatever in this respect. Without careful examination, the fine threads might easily be taken for fibrinous remains of an old iritis, but they can be distinguished from these by observing that they spring from some portion of the anterior surface of the iris, usually by two or more fibrous roots, while an iritic exudation comes from the lower surface of the iris, or at most adheres to the pupillary margin. Only the rare membranous form calls Fig, 13"2. — Case of uapsulo-pupillary menibraue with surrounding white ("paint") spots ou capsule. for any operative interference. I have seen several cases in which discission of the lens was necessary, on account of the amount of visual defect which the condition occasioned. Anterior Chamber. Individual differences exist in healthy eyes in the depth and shape of the anterior chamber. Changes are also con- tinually taking place in health, according to the state of accommodation. When the eye is accommodated for near objects, the middle of the chamber is shallower, and the periphery deeper, than in the case of accommodation for dis- tance. In very young infants and very old people the chamber is shallower than at other periods of life. In the former case this 30G DISKA8E8 OF THE IRIS AND CILIARY BODY. is owing to the globular shape of the lens and the imperfect development of the eye altogether ; in the latter, to increase in the size, and })ossibly also to advancement, of the whole lens. The anterior chamber is pathologically increased in dei)th in two ways : by an alteration in the normal position of the lens, and by a change in the normal curvature of the cornea. Thus wc often find a deej) chamber when the lens is absent or dis- located, and also when it is pushed backwards by excessive secretion ; or when a retraction takes place, owing to the shortening of organised exudation in the vitreous chamber. It is a))normally deep, too, in cases of conical cornea, cornea globosa, and staphyloma of the cornea. Diminution in depth of the anterior chamber results from causes w^hich lead to advancement of the iris or lens, or flatten- ing of the cornea. Exclusion and occlusion of the pupil give rise to an accumulation of aqueous humour behind the iris, which is consequently jmshed forward, and the chamber in that way shallowed. Shallowing of the chamber is also met Avith in glaucoma, and in the second stage of intra-ocular tumours. In old cases of irido-cyclitis, too, and in some cases of detached retina, the anterior chamber is shallowed, owing to atrophy of the vessels of the iris and ciliary body, and a consequent diminu- tion in the secretion of aqueous humour. Alteration of the sha2ie of the chamber — retraction of the periphery and advancement of the pupillary portion of the iris — is met Avith, and is an important point in the diagnosis of metastatic choroiditis in children, or what has been called j^seiido- f/lioma. The contents of the chamber, too, are subject to pathological alterations. Thus the normal clearness of the aqueous is dis- turbed in many cases of iritis. Dislocation of the lens may also take place into the chamber. Along with septic inflammation of the cornea, or purulent iritis, or cyclitis, pus may collect in the chamber (hypopyon). Injuries to the vessels of the ciliary body, or iris, may lead to a collection of blood (hyphi\3ma). Finally, foreign bodies may lie in the anterior chamber, and may or may not be surrounded by purulent exudation, according to their nature and the time they have been in the eye. CHAPTER X. DISEASES OF THE CHOROID AND VITREOUS. The Choroid. A CERTAIN portion of the choroid, namely, that whicli lies anterior to the equator of the eye, is altogether hidden from view. Pathological changes affecting this portion can therefore only be inferred from the symptoms to which they give rise. The rest of the choroid is also more or less concealed by the i:)igment contained in the hexagonal cells of the retina. When this pigment is scanty, the larger vessels of the choroid, as well as the intervascular spaces, are visible on account of the trans- parency of the rest of the retina. The blood supply to the choroid is mainly through the short posterior ciliary arteries, of which there are about twenty. These vessels enter in the vicinity of the optic nerve, at the back of the eye, and do not anastomose to any extent with each other. They form, however, pretty free anastomoses with the recurrent branches of the long anterior and posterior ciliary arteries. A considerable portion of the anterior pai't of the choroid is therefore supplied by these long arteries, and either by branches from the trunks themselves, or from the arterial rings which they form in the ciliary body. The blood returns through veins, the arrangement of which is very different from that of the arteries. The vente vorticosae, from four to six trunks, collect all the blood from the choroid, as well as much which has supplied the anterior jjortions of the eye. The numerous choroidal veins mainly join these trunks, which pass out of the eye near its equator. Some open into anastomoses, which are formed here and there between the contiguous vortex veins behind the equator of the eye. The choroid is only firmly adherent to the sclera behind at the entrance to the oi)tic nerve, and anteriorly through the ciliary body. The attachment to the sclera in other situations 308 DISEASES OF THE CHOROID AND VITREOUS. is merely through the vessels wliieh penetrate that membrane to reach the choroid. The jtigment layer of the retina adheres closely to the choroid, so that when the retina becomes detached it lea\es this layer l)ehind. Choroiditis. — As the extent to which the normal choroid is visible with the o}ihthalnioscope depends on the condition of the hexagonal pigment cells, so also does the visibility of i)atholo- gical changes in the choroid. Considerable alterations may have taken place where there is yet nothing to be seen with the ophthalmoscope ; indeed, in some instances, it is only when the jiathological process in the choroid involves the retinal pigment cells that ophthalmoscopic changes are observed. Strictly speaking, then, in the case of inflammations of the choroid, characteristic ophthalmoscopic appearances are only seen when the retina is involved as well — that is, when the condition is one not only of choroiditis but of choroido-retinitis. From a clinical I)oint of view, however, an inflammation beginning in the choroid, though afterwards s})reading to the outer portions of the retina, is a choroiditis. Such inflammations have altogether a different origin from cases of true retinitis, or inflammation of the nerve elements, or of the connective tissue of the retina. Choroiditis, besides causing retinal changes, may give rise to more or less marked changes in the transparency and con- sistency of the vitreous. In certain forms, too, the sclera is at the same time weakened, so that alterations in the shajje of the eye take place, leading to more or less disastrous con- sequences. There is a great tendency to a patchy arrangement in choroidal inflammation, or to what is called disseminated choroiditis, but in some cases, and more especially in the serous and purulent varieties, the inflammatory changes are diffused over the whole membrane. Disseminated choroiditis. — The ophthalmoscopic appearances met with in disseminated choroiditis are due to localised exuda- tions into the choroid, alterations in the retinal jiigment, and eventually also to atrophy of the choroidal stroma. The patches of exudation and degeneration, which sooner or later become visible, vary greatly in shape and size. They are often ap- proximately circular, but they may be of any other form, not unfrequently crescentic, or dumb-bell-shaped. By their con- fluence they assume all kinds of irregular forms. They differ in appearance according to the stage arrived at by the inflamma- tion. Different foci of inflammation may exhibit diflerent stages at the same time. In the beginning the spots are yellowish, or DISSEMINATED CHOROIDITIS. 309 reddish yellow, and show little or no trace of choroidal vessels. Their mai'gins are not very sharply defined, and there i.s occasionally some degree of prominence evident. These appear- ances correspond to the stage of hypertemia and exudation. Old-standing patches, which have reached what may be called the degenerative stage, are white, with traces of the remains of choroidal vessels, and they are not prominent ; their margins are sharply defined, even punched-out looking, and often bordered with pigment. The white appearance of the patches is due not Fig. 133. — Disseminated choroiditis. only to the cicatricial changes which take place in the ex- udation, but to more or less reflection as well from the sclera, which is less obscured than when covered by normal choroid. As the transition from one stage to another takes place, the change to white is seen first to occur in the centre of the patches. While the appearances just described enable one to distinguish the evident exudative from the evident degenerative stages, there are many cases where the diagnosis of the stage is by no means easy, and may be impossible. This is the case mainly 310 DISEASES OF THE CHOROID AND VITREOUS. where the i)rincipal changes seem to be limited to the pigment layer of the retina. The choroidal structure is then well seen in the area of the patches, and the main ditterence, caused by time, is in the amount and arrangcmoit of the pigment masses bordering them. In a not uncommon variety of disseminated choroiditis, one wliich seems usually to be a manifestation of hereditary syphilis, the i)atches are small, circular, and bordered by dense crescentic masses of pigment. In some cases of choroiditis the [)igmentary 134. — Recent disseminated choroiditis. changes are not limited to the region of the patches in the choroid, but are met with in the shape of irregular spots in the more superficial parts of the retina. Choroidal patches may form first in the region of the equator of the eye, and gradually invade more and more of the choroid, spreading towards its central portion, as well as anteriorly ; or they may be confined to the region of the papilla and macula. It is hardly possible to say, from the ophthalmoscopic appear- ances in any case of disseminated choroiditis, to what extent the vision has been reduced. In many cases the most extensive ophthalmoscopic changes are met with where the visual acuity DISSEMINATED CHOROIDITIS. 311 is found on examination to be hardly, if at all, subnormal. Often, however, in such cases where the vision is found to be so good, there is some degree of night blindness and cloudy vision. The subjective symptoms are altogether more marked in the exudative than in the atrophic forms of the inflammation, the occurrence of fresh patches of exudation being accompanied by subjective sensations of light and colour, as well as by positive scotomata. The degree of visual disturbance and other sub- jective symptoms depends in great measure on the site occupied ^i^: A Fig. 135. — Circumscribed central choroido-retinitis in atrophic stage, showing also annular staphyloma posticum. — After Wecker and Masselon. by the patches of inflammation. Patches at or near the macula necessarily cause much greater interference with vision than those situated more peripherally. Frequently the vision, which has hitherto been more or less good, all at once becomes very much deteriorated, without any marked change being visible in the ophthalmoscopic appearances. The reason of this is, that a fresh patch has formed at the fovea, or, it may be, a previously existing change in that situation has so far 312 DISEASES OF THE CHOROID AND VITREOUS. altered as to involve the j^ercipieiit elements of the retina, which up to that time have escai)ecl. Central patches give rise at first to distorted vision, or metamor- phopsia. At a later stage this may be followed by a positive scotoma, or a blind spot, of which the patient is conscious, and which he projects in front of his eye as a clouded or ]>lack figure, the size of which increases with the distance of the i)lane of }iro- jection. The scotoma is at first only seen in subdued light, and clears away as the surrounding illumination becomes greater, or Fig. 136. — Disseminateil tlioroiditi.s showing marked iiigmentary changes. the object fixed is brighter. In testing for positive scotomata, therefore, the test should 'be made in subdued light. The metamorphopsia is due to a change, produced by the exudation or other alteration of the choroid, in the relative positions of the percipient elements of the retina, which causes a difference in the external projection of the impressions which they receive. In the case of a fre.sh exudation, the retinal elements are abnormally separated, so that a smaller number of them come to occupy the same superficial area as before ; or, in other Avords, the same number of elements are spread over a larger area than under normal conditions. The image of any DISSEMINATED CHOROIDITIS. 313 object falling on such an area produces stimulation of a smaller number of retinal elements than it would otherwise do ; but the jjrojectiou being unaltered, this is not compensated for, and the object appears diminished — that is to say, such changes give rise to micro2)sia. On the other hand, the shrinking result- ing from the contraction of an old exudation, or from some atrophic change, may lead to a greater approximation of the retinal elements in the area involved, so that the same number Fig. 137.— Showing distortion of parallel lines round point of fixation (micropsia). Fig. 138. — Showing distortion of parallel lines in the case of niacropsia. of elements come to be spread over a smaller space than they originally occupied. Such an approximation gives rise, for similar reasons, to an unnaturally large apparent image, or to macro2Jsia. The best method of testing whether or not any metamor- phopsia exists (and it may be present without being spontane- ously complained of) is to cause the i»atient to fix a mark in the middle of a number of parallel line.s, a few millimetres apart, and to say whether they appear to him to run parallel, or to 314 DISEASES OF THE CHOROID AND VITREOUS. bend outwards or inwards at any particular place. In this way we may detect not only the existence of a localised nietamor- phojjsia, but also whether we have most probably to do with a recent exudation causing a distension, or an old exudation or atrophic change which lias led to a contraction and api)roxima- tion of the retinal elements in the corresponding area. Besides the defect in visual acuity caused by changes in the external layers of the retina, there may be other changes which have more or less influence on the vision, according to the site of the choroidal exudations. When the area attacked is in close proximity to the papilla, there is often found to be hyperiemia of the disc, with some interference with the trans- parency of the vitreous. This hyperemia is the result of a participation by the scleral vascular ring in the congestion of the choroidal vessels. Again, an extension forwards of the inflammatory changes is apt to bring about a complication with cyclitis or even iritis. What the exact connection is between choroiditis and opacities of the vitreous is not very clear, more especially why such opacities should occur in some cases and not iu others. The etiology of disseminated choroiditis is very often obscure. A number of cases, and more particularly of the exudative variety, are probably syphilitic. It is very uncommon in children, in whom it is mostly a manifestation of inherited syphilis. There seems reason to suspect that some cases, par- ticularly those occurring in young adults, are of tuberculous origin. Treatment. — In the cases which are of syphilitic origin, anti- syphilitic treatment, on the lines referred to in connection with syphilitic iritis, Avill often be found to be of use. But great harm may be done by treating other cases in the same way. This is more particularly so where the choroidal inflammation occurs in young people or comes on after some debilitating illness. Fresh air and moderate exercise with tonics, esi)ecially iron, are most useful in such cases. It is certainly a mistake to confine such patients to a more or less darkened room, as is often done. They may be given dark glasses to wear outside, but should not as a rule be put under any more severe restraint. Wet packing for half an hour every morning sometimes appears to do good. Senile central choroiditis. — When the vision of old people slowly Ijut steadily deteriorates, and when on examination it is found that the field of vision is normal in extent in all direc- tions, while with the ophthalmoscope the lens and vitreous are SENILE CENTRAL CHOROIDITLS. ;15 seen to be clear, a careful exploration of the macular region should be made. For this purpose it is generally necessary to dilate the pupil. The cause of this progressive defect will, in such cases, very often be found to be an alteration in the choroid immediately behind the macula. If seen at an early stage the appearance presented by this disease is that of a reddish or reddish-yellow, usually irregu- larly oval-shaped, patch, often only very slightly differing in colour from the rest of the fundus, but always presenting a very definite outline. Afterwards the patch assumes a more atrophic Fig. 139. — Senile central clioroiditis, with circumpapillary atropliy. aspect, and the colour then presents a greater contrast to that of the surrounding ])arts ; the edges become more irregular and bordered by pigment. The patch almost always appears in both eyes, though often when first seen it is further advanced in one eye than in the other. As a rule it is little more than half the size of the papilla, but it may be considerably larger. The condition gives rise to metamorphopsia, and to the appear- ance of a positive scotoma, of the existence of which the patient is more or less conscious. Central fixation is eventually abol- ished, so that the visual acuity is reduced to ^-^*^ or less. Patients with central choroiditis are therefore unable to read ;mg diseases of the choroid and vitreous. ordinary print, but do not become quite blind, as there is no tendency for the condition to spread to other i)arts of the eye. On this account the pror/nosis is so far good, and it is therefore of considerable practical importance to make a correct diagnosis, and not confound the condition with any affection which may l)0ssil)ly proceed to blindness. No treatment appears to have any influence whatever on this disease. Syphilitic choroiditis. — While many changes recognised with Fig. 140. — Diffuse acute choroiditis, showing hypertemia of disc, vitreous haze, and superficial e.xudation. the ophthalmoscope as choroidal are more or less directly the result of syphilis, there is one form of acute inflammation which, if not invariably a manifestation of syphilis, is so at all events in the vast majority of cases. It is a late secondary or early tertiary symptom of syphilis. In more than half the cases met with, traces of other secondary manifestations are found at the time of the outbreak of the choroidal inflammation. It is most fre(juent in elderly individuals, and appears altogether more likely to make its appearance in cases where syphilis is acquired late in life. Sometimes the choroiditis follows after a few SYPHILITIC CHOROIDITIS. 317 months on an attack of iritis. It is mo.stly met with in both eyes. The objective symptoms are often very slight, namely, hyper- eemia of the disc, with faint haze of the surrounding retina, and at the same time a fine diffuse opacity in the vitreous. The hazy appearance of the retina is partly due to the veiling by the opacity in the vitreous, which is always most dense in the central portion, and partly to serous exudation in the retina itself. It clears up to some extent as the eye remains in one Fig. 111.- — Choroiditis, with marked distiubauce of retinal pigment in macular region. position during the examination, owing to the sinking down of the vitreous opacities. In a number of cases the opacities are much more dense, and render the details of the fundus more or less indistinct. In all there is a great tendency for them to continue for a long time, or to disappear and reappear at intervals. In short, the constant association with more or less dense opacities of the vitreous is one of the characteristic symp- toms of this disease. Very characteristic also is a great difference in the acuity of vision, as well as in the form of the field of vision, found on 318 DISEASES OF THE CHOROID AND VITREOUS. examination at one time in a feeble, at another in a strong, illumination. There is in fact often most marked night blind- ness. Thus one fretjuently finds that a patient who cannot read even large print when still sufiiciently illuminated not to cause any perceptible diminution of acuity in the vision of the normal individual, is nevertheless able, when the illumination is strong, to read the very smallest print. He requires a more IX)werful light than is necessary under normal conditions to evoke the full functional activity of the retina. On the other hand, Fig. 142. -Sliowiug a recent patch of central choroido-retinitis. — After Frost. when the light is strong enough, the light-difference sense does not greatly diflfer from the normal. •Subjective sensations of light are often complained of, and are sometimes i)ainfully persistent. Metamorphopsia, and especially microi>sia, is a very frequent .symptom of acute syphilitic choroiditis. The micropsia is often extremely marked, and more so for objects held at some distance from the eyes. It is most apparent to the patient where the choroiditis exists in one eye only. Acute syphilitic choroiditis may be recovered from without leaving any trace, and with perfect restoration of vision. Often POSTERIOR SCLERO-CHOROIDITIS. 319 there may afterwards be seen, on careful examination of the more })eripheral parts of the fundus, a number of yellowish spots, confined to that region. More frequently some defect of vision remains, due to the persistence of opacities in the vitreous and the gradual development of changes in the choroid, w^iich have much the appearance of other forms of disseminated choroiditis. Occasionally very dense opacities remain, and these cases are usually associated with inflammatory changes in the iris, and ciliary body as w^ell. The best treatment is, no doubt, the mercurial, and preferably by inunction, continued as long as possible without giving rise Fig. 143. — 81iowiug a large patch of reiitial clioroido-retinitis in the advanced atrophic .stages. — After Frost. to stomatitis. The patient should wear dark glasses. He should at the same time avoid stimulants and any violent exercise, and be altogether prohibited from making any attempt at reading, or using his eyes for any work necessitating accommodation, or a strong illumination. Posterior sclero - choroiditis.^-SYrt/>A///o»(a ^)os^/c?rocluced. The naine .staphyloma [Hj-sticuin is given, however, to very varying degrees of defect in the clioroid in the immediate neighbourhood of the disc. The defect may be merely due to the apertui-e in the choroid at the site of the entrance of the optic nerve being larger than that in the sclera, whereby the scleral ring becomes broadened to the outer side, showing as a crescentic white patch, with its concave margin next the disc. Such a crescent may be met with along with all states of refraction, but is more frequently seen in myopic eyes. Fig. 1-44. — From a case showing atrophic crescent at lower portion of disc. A very great enlargement of this patch may take place as the result of a slow form of sclero-choroiditis. This low inflam- matory change only takes place in myopic eyes. A similar appearance, dite to atrophic thinning of the choroid, is met Avith as a senile change. As the area of degeneration extends in a myopic eye, it comes more and more to encircle the disc, though it is usually, even when very extensive, most marked to the outer side. In a small proportion of cases the crescent lies at the lower margin of the POSTERIOR >SCLERO-CHOROIUITIS. 321 disc. It is then congenital, and i.s associated always with some defect of visual acuity. The white colour of the staphyloma posticum is due to reflec- tion from the sclera below the patch of atrophy of the choroid and pigment layer of the retina. The superficial layers of the retina are not, as a rule, implicated in the process, and, as a con- sequence of this, the retinal vessels may be seen to course over it, just as in the cases of choroiditis elsewhere. The margin of the staphyloma which is farthest away from Fifl. 145. — From a case of progressive myopia, showing staphyloma posticum and macular choroido-retiual changes. the disc may be .sharply defined, and is then, usually at the same time, the site of a greater or less pigmentation. In other cases the patch merges at tliis situation into the surrounding fundus without showing any very decided definition. Speaking generally, the first condition is an indication of an arrested, or only very slowly progressive, change, while the latter should give rise to more suspicion, as showing a greater likelihood of ^irogres- sion. In the very high degrees of stai)hyloma posticum the crescentic shape is altogether lost, and only a large white [jatch, sometimes wath here and there some pigment spots, surround the 21 3l>2 diseases of THK CHOROID AND VITHEOUS. disc on all sides. These large areas of degeneration may even involve the macula. The i)rotrusion, by increasing the antero- posterior diameter of the eye, causes axial myopia. Posterior sclero-choroiditis, which causes the higher and pro- gressive variety of myopia, often causes a dull aching pain. This ]»ain, and the evidence of progression in the degree of the myopia, as well as the defect in vision which makes its appear- ance sooner or later, are the main symi)toms of the disease being active. On the other hand, during a period of remission the vision does not alter in acuity nor the myoi)ia in degree, while at the same time the 2)ain is absent. In connection with staphyloma posticum, and what must be looked upon as the immediate cause of the defect of vision in the progressive variety of myopia with which it is accompanied, are changes occurring in the region of the macula itself. These changes are rather different in their mode of origin fi-om those characteristic of senile central choroiditis, which they may after- wards come to resemlile pretty closely. They frequently begin as a kind of irregularity in the pigmentation at the macula, which takes the form of differently shaped figures darker than the surrounding fundus. Gradually the centres of these figures ex- hibit a yellowish or atrophic coloration, which encroaches more and more on the darkened area, and eventually becomes an atrophic plaque very similar to those met with in disseminated choroiditis. Metamorphopsia is a constant symptom of this condition, and frequent complaints are made of musca?, cloudy vision, and sub- jective light sensations. The symptoms, in short, all point to irritation of the retinal percipient elements. The tfeatment is, on the whole, very unsatisfactory, especially where the condition has been going on for some time. Read- ing should certainly be avoided, and dark glasses be more or less constantly worn at times when the subjective symptoms point to activity in the infiammatory process and progression of the myopia. At the same time, it may be of use to leech or blister the tem})le. Purulent choroiditis. — A purulent inflammation of the choroid, whicli may either remain confined to that membrane or lead to inflannnation of all the tissues of the eye,—2Mnophthal- 7mtis, — occurs as the result of various lesions. Thus it may be set up by operations performed on the eye, or by penetrating wounds, with or without the lodging of foreign bodies Avithin the eye. It may follow fresh perforations of the cornea, or any accident which causes a bursting or inflannnation of a staphyloma of the cornea or sclera. PURULENT CHOROIDITIS. 323 lu a small but important group of ca.ses the etiology i.s of an altogether different nature ; in such the purulent choroiditis may result from thrombosis in the ophthalmic veins, from embolism in the choroidal arteries, or from septicaemia. The first class of cases may be grouped as cases of traumatic purulent choroiditis, the second as metastatic purulent choroiditis. Traumatic purulent choroiditis. — The symptoms of purulent choroiditis are — very great jiain in the eye, accompanied by rapid and complete loss of vision ; redness and swelling of the lids ; and chemosis. Swelling of the orbital tissues is also more or less marked, causing a tendency to protrusion of the eye, the mobility of which is at the same time interfered with, partly on account of the participation of the muscles and the mechanical difficulties which the presence of the exudation occasions, and partly, no doubt, owing to the pain alone. In cases which go on to panophthalmitis all these symptoms are more intense, and at the same time the cornea becomes more and more hazy from infiltration of leucocytes ; the aqueous humour becomes muddy and purulent ; and iritis, with hypopyon, makes its appearance. Purulent choroiditis always leads eventually to shrinking of the eye. This may follow rapidly on a spontaneous perforation of the coats, and the discharge of pus externally ; or it may more slowly result from consolidation and partial absorption of the purulent matter, without perforation. In such cases, if the lens remain clear and the pupil is not occluded, the whitish mass of partially organised lym})h may be visible. In the treatment of purulent choroiditis we cannot expect to save the sight of the eye. All that can be done is to alleviate the excessive pain from which the patient suffers. For this purpose, when vision has been lost, an opening may be made in the eye to admit of the discharge of the pus. Enucleation should not be performed at the time of the inflammation, owing to the risk that there is of thereby setting up meningitis. The question as to whether enucleation should be done or not at a later period, when the eye has shrunk and the symptoms of active inflammation have subsided, is one which, as a general rule, may be left pretty much to the patient, as there is little danger of sym^iathetic inflammation occurring in the other eye. When purulent choroiditis seems to be threatened, it would appear that it sometimes can be kept off by the application of a tight bandage over the eye. Metastatic purulent choroiditis. — By far the greatest number of cases in which a meningitis, from which the patient recovers. 3-24 DISEASES OF THE CHOROID AND VITREOUS. is accompanied by purulent choroiditis, occur in very young children. Often such cases are first seen by the ophthalmic surgeon after the meningitis has subsided. The inHammation in the choroid leads to shrinking of the globe, I'arely to iianophthal- mitis. And the appearance which the eye then presents is that which in this country is often called jisendo-gh'oma. The iris is then muddy, more or less atroj^hied, and pressed forward by the lens, so that the irregular i)Ui)il comes to lie close up to the clear cornea. The peri})hery of the iris is, however, in most cases retracted, sometimes markedly so. Through the lens, which usually remains clear, a white mass can be seen lying iu the vitreous. The tension of the eye is diminished, and there is complete blindness. It is seldom that any difficulty can arise in the differential diagnosis between this condition and true glioma, which also occurs in children ; the retraction of the iris at the angle of the anterior chamber, and the diminished tension, are sufficiently characteristic symptoms. Choroiditis following meningitis is ])robably due to direct transference of iufiammatory products along the sheath of the optic nerve. One or both eyes may be affected, more frequently only one. There apjjears to be no danger of sympathetic in- flammation of the other eye where one eye alone is affected, and therefore enucleation is not necessary. The evidences of the meningitis are not always equally marked. Sometimes there have been distinct convulsions, at other times only loss of appetite and drowsiness, with the history of sudden redness and swelling of the eye, and a yellow kind of glimmer from the interior. This appearance, with the chemosis and hypopyon, and the evident interference with vision, distinguish the cases from simple iritis. Purulent choroiditis in one, sometimes in both eyes, leading to complete destruction of sight and to shrinking of the eye, either from perforation, or absorption and organisation of the deposit in the vitreous, may occur in pyaemia, puerperal fever, erysipelas, and ulcerative endocarditis, as well as in connection with inflammations, both idiopathic and traumatic, about the head or face. I have seen several cases occur in the course of an influenza. These have been due to a pneumococcus or stre[)tococcus invasion. The immediate cause of the inflam- mation is probably not always the same ; yet it is often, no doubt, as has actually been demonstrated, due to embolic in- farcts iu the choroidal vessels. There seems, too, to be a special disposition to marantic thrombosis, under the influence of sepsis, RUPTURE OF THE CHOROID. 325 in the finer vessels of the choroid, as it is ahnost solely in this region of the vascular supply from the carotids that metastasis is found. About one-third of the cases of metastatic choroiditis are bilateral. Ulcerative endocarditis has been found by Axenfeld to be present in one-half of all the cases of bilateral metastatic choroiditis occurring in different pyemic conditions. The frequency of this association is not so great in unilateral cases. The worst cases of streptococcus invasion are therefore more likely to cause both the choroidal and the endocardial mischief. In cases, again, of thrombosis of the cerebral sinuses, we may find a pretty sudden protrusion of the eye, with amblyopia or amaurosis, a dilated and motionless pupil, and more or less chemosis of the conjunctiva and oedema and redness of the lids. This may occur on both sides, but is most frequently found on one side only. Probably the thrombosis in the sinuses is not sufficient of itself to give rise to the choroiditis, but must be associated with thrombosis in the ophthalmic veins as well. Such cases always end fatally. The process may begin in the sinuses of the brain and spread to the ophthalmic vein, or it may result from a phlebitic process in the neighbourhood of some inflammation in the face, and spread back to the sinuses. In the first case there may often be great difficulty in diagnosing between the thrombosis of the sinuses and meningitis, as the cause of the panophthalmitis. When it occurs on both sides, more especially with an interval between the appearance of the infiammation in the two eyes, thrombosis would appear to be most likely. The state of the pupil may sometimes be of diagnostic importance in this respect : — in thrombosis it is generally dilated and motionless, while retaining its normal form • in choroiditis from meningitis, on the other hand, it may be irregular, and bound down by synechia. Rupture of the choroid. — The choroid may be ru^itured, partially or completely, by a blow on the eye with some blunt object, and with or without there being a rupture of the retina at the same time. The same injury may give rise to retrover- sion or separation of the iris, dislocation of the lens or other lesions in the anterior segment of the eye, but often the rupture of the choroid is the only change produced. The sclera immediately behind the ruptured choroid never gives away. Ruptures of the choroid take place near the posterior part of the eye, and possibly at the anterior part, where they cannot be seen with the ophthalmoscope. They may be to either side of the optic nerve, or above or below it, and almost always coincide 32G DISEASES OF THE CHOROID AND VITREOUS. roughly with segments of circles described round the papilla as a centre. Bifurcations may occur, and in some instances two or more distinct and concentric ruptures may take place. '^oTlie oplithalmoscoiiic appearances vary according to the com}i]etencss of the rupture and the length of time which has elapsed since the'accident. If the eye is examined immediately after the injury, the rupture cannot, as a rule, be seen, but the retina is found to be swollen and hazy, and more or less veiled. Fig. 146. — ltu}iture ol' choroid (invertud image). In a few days this haziness in the retina disappears, and a sharply cut linear yellowish figure, concentric wdth the papilla, and over which the retinal vessels are seen to pass, makes its appearance not far from the i>apilla. This gradually becomes more and more white, and in the course of time is here and there pigmented. Pigmentary changes also often develop in other parts of the surrounding retina, particularly in the immediate vicinity of the optic disc. Rupture of the choroid generally causes very little bleeding, but the nature of the lesion COLOBOMA OF THE CHOROID. ;}27 may remain for some time undetected owing to the bleeding from the iris, which has been injured at the same time. The extent of the injury to vision differs very much in different cases, depending on the position and extent of the rupture. In large ruptures the vision is always permanently much reduced. Even small ruptures, if they take place immediately behind or close to the macula lutea, cause great interference with sight. In almost all cases the vision is much reduced innnediately after the accident, and gradually improves Fig. 147. — Coloboma of to a greater or less extent as the oidema of the retina passes off Coloboma of the choroid. — Just as in the case of the iris an arrest of development may lead to the non-closure or imperfect closure of the fretal fissure, so in the choroid a similar defect may result from the same cause. Coloboma of the choroid is most frequently associated with coloboma of the iris, but may be present alone, and be found in one or both eyes. The true coloboma of the choroid is always met with downwards, or downwards and inwards. The defect is usually 328 DISEASES oK THE CHOROID AND VJTREoUS. narrower in the region of the papilla, which may or may not be inchided in it, and broader towards the periphery. In all cases the retina is either completely absent, or only very imperfectly developed, in the region of the coloboma. There is therefore alwaj^s a more or less complete scotoma, corre- sponding in extent to the coloboma. On oi)hthalmoscopic examination a brilliantly white rctiection ia seen from the region in which the i*etina and choroid are defective. The surface of the coloboma is never of an ecpiable colour throughout. Here and there, there are often to be seen masses of pigment. The white area, too, is often broken up by a number of ditterent sized, very ill-detined, faintly bluish spots, corresponding to irregularities in the sclera, which is laid bare by the absence of the choroid, and the reflection from which causes the marked, almost dazzling, whiteness which is pre- sented by the ophthalmoscopic picture of a coloboma of the choroid. Vessels are also seen to course across the white area in different directions. These are l.)oth ciliary and retinal vessels. In many cases of coloboma only line and narrow branches of the retinal vessels cross the coloboma, and in some there is an absence of retinal vessels altogether. This depends entirely, no doubt, on the degree to w^hich the defect in develo})ment has involved the retinal structures which lie anterior to the pigment layer. When the disc is included in the coloboma, it may retain its normal appearance, but it is more often so altered as to be barely recognisal>Ie. There is a rare form of coloboma in which the ilefect occupies the region of the macula alone. This is i)rol)al)ly the result of degenerative inflammatory changes which have taken i)lace in intrauterine or infantile life. It may produce astonishingly little defect of vision. Tubercle of the choroid. — Tul)crcle occurs in two forms in the choroid — as miliary tubercle and as larger tuberculous masses. The first form is acute, and always secondary to tubercle in other organs. The second is chronic, and may or may not be primary. Chronic tuberculous choroiditis is certainly very rare — nuich more so than miliary tuberculosis. It occurs in one eye only, and appears sooner or later to be associated with similar disease of the brain, which ends fatally. The ophthalmoscopic changes in the cases which have been described have been those of o})tic neuritis (obliteration of the margin of the disc, great engorgement of veins, with sometimes hi^^morrhages here and TUBERCLE OF THE CHOROID. 329 there), and a ditFiise white coloration over a hirge jiortion of the fundus. From sarcoma it may be distinguished by the flatness of the swelling when com])ared with its superhcial extent, by its more or less distinctly nodular form, and by the evident inflammatory changes in the surrounding choroid. It differs from purulent choroiditis in there being no history of injury, or any condition likely to set up that form of inflammation, as well as by its being relatively more circumscribed and localised to one portion of the choroid. Miliar// tubercle of the choroid is only met with in cases where there is already, or, much less frecjuently, where there is afterwards, an infiltration of the same nature in a numljer of other organs. It is probably never met with where tubercles exist in the lungs alone, and it appears to have no definite relation to tuberculous meningitis. In fact it is if anything least common in children in whom tuberculous meningitis is most common. As the tubercles are late of appearing in the choroid, or at all events of becoming visible on ophthalmoscopic examina- tion, it is seldom that the diagnosis of general tuberculosis is facilitated by the use of the ophthalmosco})e. When present, they afford a positive proof of the tuberculous nature of the general disease, while their absence does not exclude the possi- bility of it. It appears certain that choroidal tubercles occur at some time or other in by far the greatest proportion of all cases of miliary tuberculosis. A considerably larger nund)er of tubercles is always found on })Ost-mortem examinations than can be seen with the ophthal- moscope. This is due jiartly to some being located in that part of the choroid which cannot be seen, but mainly to their not all having advanced so far as to destroy the pigment layer in front of them. When making their appearance, as they often do, only a few days or hours before death, the state of the i)atient may be such as to render an ophthalmoscopic examination difficult. Miliary tubercles generally occur in both eyes, sometimes only in one, and always in the choroid — never in the retina. They are always round, and vary in size from one-sixth the dia- meter of the papilla, or less, to (piite half as big again as the papilla. Usually the size in any particular case is from one- third to two-thirds the diameter of the papilla. The larger ones are distinctly prominent. Their colour is very distinctive, and makes it all but impossible to confound them Avith any other form of patch characteristic of the numerous varieties of dis- 330 DISEASES OF THE CHOROID AND VITREOUS. seininated choroiclitis. There is a regular transition from the normal red colour of the fundus at their margins to a dull yellowish-white at their centre. Haemorrhages in the choroid. — Htemorrhages are hardly of such fre(iueut occurrence in the choroid as in the retina. The smaller choroidal lueniorrhages may usually be distinguished from the retinal ones by their not having any constant relation to retinal vessels, and not presenting the Hame-shaped a])i)ear- ance which characterises retinal ha'incjrrhages in the nerve fibre layer. When near the retinal vessels, these vessels may some- times be seen to pass over them. Large choroidal luemorrhages, again, are not bordered by such a sharp and regular line as is the case in large I'etinal extravasations. It is imi)ossible, how- ever, with certainty to diagnose the position of a haiuiorrhage, as those originating in the deep layers of the retina, wdien of moderate size, exactly resemble hiemorrhages in the choroid. There is more tendency, possibly owing to the resistance offered by the lamina vitrea, for a choroidal luemorrhage to pass back- wards than into the retina. When large, the choroid may be detached ]>y the accumulation of blood between it and the sclera. Choroidal haemorrhage may be of traumatic or idiopathic origin, and, according to its extent and the position of the exti-avasation, may interfere greatly or not at all with sight. On absorption it leaves an atroj)hic patch, bordered with pigment. Ossification of the choroid. — In eyes which have been lost by irido-cyclitis, accompanied by an exudative choroiditis, true bone may in the course of time be found in the choroid. The plate of bone formed takes the shape of the inner surface of the eye. The formation always ceases at the border of the ciliary body, in which ossification never takes jjlace. I have also always seen an aperture left at the position of entrance of the optic nerve. As the eyes in which ossification takes place are otherwise destroyed, the diaynosis can only be made by feeling a hard body, which ends sharply some 4 or 5 mm. from the corneo- sclera margin. The presence of bone in the choroid is usually associated Avith irritation and j^ain, but it is not liable to give rise to sympathetic infiammation. The treatment should be enucleation. Diseases of the Vitreous. Acute purulent infiammation of the vitreous may occur when a foreign body is lodged in it, or it may be the result of the OPACITIES OF THE VITREOUS. 331 extension of some iuflamnaation from other parts of the eye. When once it is set up, the eye is doomed, and eventually shrinks. This result may or may not be preceded by perforation, with evacuation of more or less pus. Less severe inflammatory con- ditions of the vitreous probably never occur primarily, but are always associated with inflammation of the ciliary body, choroid, or retina. Clinically, however, the condition of the vitreous is often the point of primary imjjortance, as the passage of inflam- matory exudation into its substance gives rise to opacities, on the existence of which the defect of vision accompanying the parti- cular inflammation may mainly or entirely depend. This is, for instance, the case in cyclitis, and to some extent also in syphilitic choroiditis. Opacities of the vitreous may be stationary or floating. They may be dift'use and punctiform, fllamentous, flaky, or mem- branous. These opacities are mainly of two kinds, either due, as has already been said, to products of inflammatory exudation from the vascular membranes of the eye, or to the effusion of blood from the vessels of these membranes. As the result of exudation into the vitreous, the gelatinous consistency which it normally presents may become altered. The vitreous may thus become abnormally liquid or abnormally condensed and shrunken. Liquefaction of the vitreous, or synchisis, may be diagnosed with certainty when that body contains more or less organised opacities which alter their position with great rapidity with the movements of the eye. All cases of liquefaction of the vitreous are not accompanied by floating opacities. The diagnosis of liquefaction without opacity may be ex- tremely ditflcult. The cause of such cases, too, is often very far from being apparent. Condensation of the vitreous, on the other hand, may generally be inferred when, along Avith more or less dift'use and stationary opacity, there is considerable diminu- tion in the tension of the eye. This condition is likely sooner or later to be complicated by detachment of the retina. Diffuse opacity of the viti'eous is a most constant accom- paniment of syphilitic choroiditis. This causes, as a rule, greater visual disturbance than circumscribed floating opacities, the patient complaining of a cloudiness over the objects seen, and often at the same time describing this veiled appearance as swaying to and fro. Such diffuse opacities frequently partly clear away, and then reappear several times during the course of the disease. They usually last for mouths, and eventually, as a rule, entirely disappear. U-2 DISEASES OF THE CHOllOll) AND VITllEOUS. I^xiidatioiis or cH'usioiis soinutimcs coagulate into tilainentous or throacl-like ojtai-itit's, which, when freely movable, are pro- jecteil by the patient as snake-like black ol)jecta, which are continually changing their shape and i)osition. Membranous opacities are either free, and capable of assuming, as they fold or Flu. 1-18. — Showing loniiutiou of fine blood vessels in vitreous. — After Frost. unfold, numberless forms ; or they are fixed to the jiapilla or retina, and only sway about at their free ends. Sometimes these fixed membranes contain newly formed blood vessels, but the vas- cularisation of vitreous opacities is rare. Bleeding into the vitreous takes place owing to the giving way of some vessel or vessels in the retina, choroid, or ciliary OPACITIES OF THE VITREOUS. 333 processes. This may be the result of a trauma, or be due to a diseased state of the vessels or of the blood. When the patient observes the pretty sudden defect of vision which such a bleeding may occasion, the cloud or veil which comes in front of his sight often appears at the same time of a distinctly red colour. When the extravasation is very large, the blindness produced is pretty complete. ]\Iost commonly, however, only a portion of the vitreous is infiltrated with blood, and as this gradually gravitates to the most dependent part, the cloud is generally thickest in the upper portion of the field of vision. Great differences are observed in the rate of absorption of the blood, ditferences which depend partly upon the age of the patient, and partly, no doubt, also ujton the state of the choroid and retina. Often a particularly slow absorption is really due to the recurrence every now and then of htemorrhages before a previous extravasation has properly cleared away. The absorp- tion may be complete, or may leave Haky or irregularly shaped opacities, which alter their position with the movements of the eye vnth more or less rapidity, according to the consistency of the vitreous. These masses are projected as black spots or patches, which appear to be constantly in motion when the eye is moved, and to fly or move slowly upwards when it has come to rest. When the normal consistency of the vitreous has not been much interfered with, the blood clot may keej) pretty much in the line of sight, and thus greatly interfere with vision ; or the patient may learn, by making a sudden movement of the eye, to get rid of the dense cloud for a few seconds, and thus be able to read ; but he has constantly to repeat this mo^'ement, and is only able to make out a few words, it may be, at a time. This symi)tom of only being able to read a few words at a time without suddenly altering the direction of fixation is cpiite characteristic of a large blood clot in the vitreous. To ophthalmoscopic examination the blood lying in the vitreous appears red if fresh, and black if some time has elapsed since the extravasation took place. Often the red reflex from the surface of the blood clot may be made out by oblique illumination, if the eye be brought as nearly as possible in a line with the convex lens. It appears to be more commonly the choroid than the retina from which extravasations of blood take place into the vitreous. At all events, subsequent changes are most frequently found in that coat. A somewhat rare but distinct clinical tyi)e of disease is the occurrence of repeated haemorrhage into the vitreous in young 334 DISEASES OF THE CHOROID AND VITREOUS. individuals. It seein.s to result from periodic capillary liy- pent'inia of the choroid. It i.s most common in young men of effeminate, as distinguished from active or energetic, tempera- ment. In some cases recovery is eventually complete, though when there have been repeated attacks this is not generally the case. It appears possible that some may proceed to the formation of connective tissue bands on the retina, and thus be the beginning of retinitis proliferans. A peculiar form of vitreous o})acity, which gives rise to a very beautiful ophthalmoscopic appearance, is that caused by the accumulation of cholesterine and other crystals in the vitreous. As at the same time the vitreous is liquid, this con- dition has received the name of si/nchisis scintillans, from the glistening caused by the reflection of light from the surfaces of the crystals. On ophthalmoscopic examination the glittering spots, which have much the appearance of small particles of gold suspended in a liquid, are seen to dance about with the slightest movement of the eye. The condition is one met with almost exclusively in old people. When found in younger eyes it is usually, if not invari- ably, secondary to some serious alterations which have very much impaired the sight. It often remains stationary for years, and does not admit of, or indeed call for, any treatment. The 2}rorinosis in cases of vitreous opacity depends on the extent to which the organisation of the opacities has gone. When the eye is otherwise healthy, even opacities which have lasted for several months may eventually disappear. When the vitreous is very liquid, — especially if, at the same time, there are extensive choroidal changes, — the condition is not likely to improve. The treatment has mainly to be dii'ected against the cause of the opacities, so far as that can be discovered. Such methods of promoting absorption as pilocarpine injections, wet packing, etc., should l)e tried. Persistent hyaloid artery. — -In the embryo an artery passes from the central artery of the retina to the back of the lens, where it divides into a network of vessels destined for the nourishment of the lens. This disappears altogether before the end of fcBtal life, but the transparent sheath by which it is surrounded persists, and forms the so-called central canal. Very rarely more or less pronounced rudiments of the artery remain. In such cases an opaipte, usually somewhat tortuous, cord can be seen with the ophthalmoscope to stretch from the centre of CYSTICERCUS IN THE VITREOUS. 335 the papilla forwards to the back of the lens. Sometimes there is at the same time some other persistence of a foetal structure, such as remains of the pu})illary membi-ane, etc., and the vision is generally not of normal acuity. Cysticercus in the vitreous. — The presence of a cysticercus in the eye is altogether an extremely rare occurrence in this country. Its development takes place between the retina and the choroid, and gives rise to detachment of the retina. At this stage it is almost always possible from the colour and shape to diagnose the cause of the detachment. Later on, perforation of the retina takes place, and the parasite passes into the vitreous. The treatment consists in attem})ting to remove the cysticercus. Such operations have been frequently ]ierformed, and with very great success. Vision is not always preserved, but in most cases, at all events, the eye comes to I'est without shrinking, and ■without the necessity for enucleation. The best chances are presented by cases in Avhich the vesicle is still subretinal. The success of an operation depends greatly on the correctness with which the position occupied by the cysticercus can be localised. CHAPTER XL FOREIGN BODIES IN THE EYE. Foreign bodies in the anterior chamber.- — A foreign body may enter the anterior chanil)er by passing directly through the cornea; or it may reach this position after penetrating through the iris or lens, entering the eye thi'ough the sclera. The wound in the cornea is generally in its lower half, as the ujjper is mostly covered l)y the lid, but it sometimes happens that the lid is perforated before the cornea. In that case, however, the force of propulsion mostly carries the body deeper into the eye, lodging it in the vitreous, or choroid, or sclera, or even in the orbit beyond. A foreign Ijody in the ajiterior chamber may cause more or less severe intlammatiou of the iris and adjacent parts, leading in the worst cases, if it is not removed, to eventual destruction of the eye. The inflammation, on the other hand, after con- tinuing for some time may subside, and the foreign body become encapsuled. In some cases it hapjiens that the foreign body lies free in the anterior chamber, Avithout producing any irritation, or it may become absorbed, with or without at the same time setting up intiammatory reaction. The first result is by far the more common. It occasionally happens that the inflammation produced is limited to the anterior jiortion of the eye, and this may eventually lead to })erforation, and ex}»ulsion of the foreign body through the cornea. More frequently, how- ever, the i»resence of the fox'eign body causes either slow insidious iridocyclitis of the worst t3^pe, or more active purulent irido-choroiditis, which is followed by phthisis bulbi. Encap- suling is very rare, l)ut it not so infrequently happens that no irritation is i)roduced at all ; and this result is most common when the foreign liody is a piece of coal or carbon, or of some chemically inactive metal. No doubt the effect produced will de}iend in great measure upon whether or not septic matter has been introduced into the IN THE IRIS. 337 eye at the same time. It is not easy in any given case to make sure of this point ; but as a general rule hot pieces of metal are aseptic, and accidents with such }»ieces admit of a better pro- gnosis from the first. Something depends on the nature of the metal itself. Copper, for instance, even if aseptic, gives rise to much more irritation than steel or iron. Foreign bodies in the iris. — The iris is on the whole a rather uncommon site for a foreign body within the eye, as the force Avhich propels it so far is mostly sufficient to carry it farther. The presence of a foreign body in the iris is likely to lead to much the same results as those just described when it lies in the anterior chamber. Absorption is less likely, and encapsuling more likely. The first effect which a foreign body produces in the iris is to give rise to hjemorrhage, which in most cases is so slight as to already have become absorbed, or to have left but faint traces, by the time the case comes under observation. Most frequently this is followed by iritis, the symptoms of which do not become prominent until a day or two after the accident. According to the size and nature of the foreign body, and the presence or absence of micro-organisms, the iritis, which its presence pro- duces, may be purulent, or merely plastic. In the first case, the complete destruction of the eye takes place rapidly by panoph- thalmitis ; in the second, the foreign body may become encap- suled, or infiammation may uninterruptedly, or by recurrent attacks, cause loss of vision in the way commonly met with in cases of old-standing iritis. Foreign bodies in the posterior aqueous chamber. — Foreign bodies usually lodge in the posterior aqueous chamber by pene- trating the eye slantingly, at or near the cornea-scleral junction. Sometimes the external wound is found to be in the central portion of the cornea. A foreign body in this position almost invarial)ly, and especially if it be of any size, sets up infiamma- tion in the iris and ciliary body, and often gives rise at the same time to cataract. llie diapearancc of a scar. If none be found on the cornea, the sclera should also be examined, but the absence of any visible cicatrix there is not conclusive evidence against the previous existence of a wound. 22 338 FOREIGN BODIES IN THE EVE. Fortunately for tlie diagnosis, the wound produced l)y a foreign body lying in the anterior section of the' eye is found to be at least nine times out of ten in the cornea. When a fresh wound or scar is discovered in the cornea, the question arises, has or has there not been i)erforation 1 To determine this we must observe — the shape of the ]>u})il, the depth and contents of the anterior chanil>er, the condition of the iris and lens, and the tension of the eye. We must also notice whether any synechi;e, anterior or posterior, have formed, or whether there is any prolapse of iris or vitreous, or any trace of uveal i)igment in the corneal wound. It is only in the case of relatively large foreign bodies that the tension is reduced or the chamber shallowed, unless the patient hapi)eus to be seen immediately after the accident, when the diagnosis of the per- foration is easier. Any prolapse is of course a certain evidence of perforation, while wounds of the iris or lens, hyphaima, hypoi)yon, and synechitv, point more or less conclusively to the same. When taken along with the history of the accident having been caused by a small body, any or several of these evidences of perforation render it extremely probable that a foreign body is lodged in the eye, and the next point is to determine whei'e. In the first place, is it in the anterior or posterior section "? The most important aid towards the solution of this point is afforded by the examination of the vision and field of vision. In all cases where the anterior portion of the eye is the site of the foreign body, the vision corresponds to the visible optical changes, whereas this is not the case where the posterior portion of the eye is that into which it has penetrated. If it be in the posterior aqueous chamber, the diagnosis is always difficult, as it is always hidden by the iris, unless, as sometimes happens, a portion of it may be sticking out beyond the pupillary margin, where it may be seen, if the aqueous and cornea be clear. When in this position, it often haj)})ens, too, that the iris has been penetrated, and the diagnosis thus facilitated. The pi'esence of a foreign body in the posterior chamber, if it is not very small, is always indicated by a protrusion of the iris over it, or by a drawing up of the pupil towards the spot. Sometimes these appearances are so slight as to make the supposed cause very uncertain, and indeed, it occasionally happens that the diagnosis of the presence of a foreign body in this position is impossible. Although the anterior chamber and iris are freely exposed to view, the existence of a foreign body in either position is not always easily diagnosed. When in the anterior chamber, it may IN THE POSTERIOR AQUEOUS CHAMBER. 339 have sunk clown into the angle, and, if small, be difticult of detection ; or the cornea may be hazy at its periphery, or the chamber occupied by more or less pus or blood. When of any size, if the cornea is clear, and there is no hypha^ma or hypopyon, the body can generally be seen, either, in fresh cases, in its natural state, or, in cases where some time has elapsed since the accident, surrounded by lym})h, appearing then usually as a sharply defined yellowish mass. When not thus directly visible, the points which nevertheless render the diagnosis of its presence more or less certain, are a localised circumcorneal injection, and tenderness to pressure, with some retraction of the pupil in a particular direction, usually downwai'ds, where the foreign body commonly lies. Apart from this, the existence of inflammatory reaction, the severity of which would be greatly out of propor- tion to the trauma if no foreign element existed in the eye, is of very considerable diagnostic importance. If in the iris, a foreign body can generally be seen, though, if small, some care is necessary in the examination, and a doubt may sometimes exist as to whether a particular appearance is actually caused by the presence of a foreign body, or is merely a pigment spot. Sometimes, when the iris is prolapsed, the foreign body is found in the prolapsed portion. Treatment. — Very small portions of iron or steel, if they have caused little irritation, may be left, on the chance of absorption taking place in the course of time, but the patient should be kept constantly under observation, so that the first symptoms of irritation, should they afterwards arise, may be noticed, and an attempt be made to remove the body. In all cases of iron or steel, the simplest method of removal is with the electro- magnet. The incision necessary for their removal should be in the corneo-scleral margin, and, except when the piece of metal is sticking in the iris, it should be made at the lower part of the cornea. The size of the incision must be regulated according to the size of the foreign body to be removed, and should always be bigger than it is, so as to prevent its being rubbed off as the magnetised probe is withdrawn. Portions of the uon-magnetis- able metals or other substances have to be removed with a curette, or pair of ribbed (not toothed) forceps. In the case of small bodies lying in the iris, the curette is usually the simplest ; for larger objects, especially when they lie free in the anterior chamber, the forceps are preferable. In any case, the wound at the corneo-scleral margin must be made of sufficient size. Should it be found, after the foreign body has been seized, that it cannot be withdrawn, and some- 340 FOREIGN BODIES IN THE EYE. times it turns out bigger than it appeared to be, the operator must not let go liis liohl of it, l)ut proceed as Itest lie can to enlarge the wound until it admits of its removal. Where any doubt exists in the diagnosis, a paracentesis, made with anti- septic precautions, so as to admit of the escape of the li(|uid contents of the anterior chamber should bo undertaken. In the case of foreign bodies embedded in the iris, it is usually neces.sary to excise the portion of iris in which they lie as well, but an attempt may be made in the first })lace to remove the foreign body alone. If this can be done without much laceration, the iris may be left ; if not, it should be excised. Foreign bodies in the jiosterior chamber are usually difficult to extract ; it is almost invariably necessary to remove a portion of iris as well — sometimes the lens has also to be extracted. The best plan is to attempt to seize the foreign body through the iris, and cut oft' all that is withdrawn through the oi)ening made for the removal. When the iris is prolapsed in an accident which renders the lodging of a foreign body in the eye possible, it should be carefully examined and bathed with an antiseptic lotion before being returned into the eye. If it is much bruised, or some time has elapsed since the accident, it is better to cut off the prolapsed portion. All operations i)erformed for the removal of foreign bodies require great steadiness on the part of the patient, and, unless this can be ensured, should not be undertaken without an anaesthetic. For such cases, in children at all events, cocaine is insufficient. How soon and how completely the irritation pro- duced by the presence of the foreign body will subside, depends greatly on its size and nature, and the length of time it has remained in the eye. The possibility of sympathetic inflamma- tion of the other eye has always to be taken into consideration in the treatment. Foreign bodies in the lens. — AVhen a foreign body enters the eye at all, it is perha[)s on the whole most fortunate for the })atient if it hai»pen to lodge in the lens. Little or no inflam- matory reaction follows, and there is, ])ractically speaking, no chance of sym})athetic ophthalmitis. Inflammation may arise owing to the wounds produced by the perforation of other super- jacent structures, principally the iris and ciliary body. A small foreign l)ody passing through the centre of the cornea, and lodging in the lens without traversing the ii"is, may produce so little irritation or disturbance as to leave the patient ignorant of having sustained so severe an injury, until the vision becomes IN THE LENS. 341 gradually more and more impaired by the advancing opacity of the lens. A foreign body in the lens, in fact, almost invariably causes cataract. In rare instances only a limited opacity sur- rounding the foreign body results, as, for instance, in the case of small particles of gunpowder. Great differences are met with in the rapidity with which the cataractous change advances — difterences depending on the size of the opening in the capsule, and the length of time which it remains open, as well as on the age of the patient. Small capsular wounds, caused by small bodies, heal of themselves ; larger ones are often plastered over by the overlying iris. A lens which becomes cataractous by lodging a foreign body is eventually partially, and in some rare instances completely or almost completely, absorbed, and the foreign body may, after a longer or shorter period, become disj^laced into such a position as to give rise to serious inflammatory disturbance. More or less irritation is always caused when the capsular wound is sufficiently large to allow of the escape of lens matter into the anterior chamber. Swelling of the lens within its capsule is liable at the same time to take place. These accidents are better tolerated in the young than in older individuals. Only very rarely do small foreign bodies lodge in the lens capsule. They cause neither much irritation nor catai'act, only a slight opacity in the capsule itself. Dia0)iterior coats of tlie eye. — The history to be obtained in cases Avhere there appears reason to suspect that a foreign body is lodged some- where in the back part of the eye is often very unsatisfactory, especially if some time has elapsed since the accident. With an uncertain history, and the absence of any external scar, the diagnosis is often a matter of no little difficulty. The j^re- ponderance of cases where the eye is pierced through the cornea is only about half as great as in the case of foreign bodies in the anterior chamber or iris. It may be taken roughly that in four IN THE POSTERIOR SECTION OF THE EYE. 345 out of every five cases the cornea is wounded, instead of nine out of ten. When a corneal wound or scar is found, the diagnosis is of course more easy. Further evidences of perforation are then looked for in the iris and lens. The vitreous must next be explored with the ophthalmoscope. Owing to the great magnify- ing power of the eye, it may be possible to see even very small foreign bodies in this situation if the opacities in the lens and vitreous are not too great. By causing the patient to look well down, it will not seldom be found lying at the bottom of the vitreous chamber, and when metallic, will be seen to glisten with a whitish or bluish-white lustre. There is just the possibility of mistaking air bubbles, which are sometimes found in the vitreous after an accident, for portions of metal. Air bubbles are round, often multiple, and glisten at the centre, while they appear dull and obscure at their margins. The glistening from a portion of metal is from its margin, the rest presenting a bluish or greenish white coloration. When the external wound has been in the sclera, it is often not easily discovered, even when fresh, owing to surrounding haemorrhage or inflammatory hyperaemia. A recent scar may be detected on oblique illumination, and perforation may be inferred when the superficial tissues are tacked down to the deeper, and not freely movable over them. In fresh scleral wounds the probe may be used carefully if doubt exists as to })erforation. If the }iatient cannot furnish satisfactory information with regard to the body by which the eye has been injured, he may possibly remember whether the vision was much aft'ected at the time of the accident or not. Obscuration lasting some days is suggestive of there having been haemorrhage, more especially if followed by black objects fioating in front of the eye ; but this is of course not conclusive evidence that anything remains in the eye. When the foreign body, or the yellowish mass of lymph by which it is surrounded, is visible by means of the oijhthal- moscojie, we may sometimes obtain positive evidence of its being steel or iron l)y observing a change of position of the whole mass on bringing a powerful magnet in contact with the eye. The diagnosis of the position of the foreign body when seen by the ophthalmoscope is easily made. When it is lodged in the coats of the eye, we find that the same lens is reipiired for accurate focussing of it as for focussing the rest of the funtlus, and that there is only very slight or no parallax. Most fre- quently in such cases there is some evidence of disturbance in the coats surrounding the foreign body — often a whitish patch, 346 FOREIGN BODIES IN THE EYE. bordered witli {lignieiit, where the choroid ha.s been ruptured at the time of its lodging in the eye. It is only rarely that the glistening of a choroidal plaque may give rise to an a]ipearance so like that of a piece of metal in the eye, that some ditticulty may be experienced in making a correct diagnosis. A piece of metal rarely if ever glistens all over, but mainly at its margins, Avhereas the glistening from a choi'oidal jilaque is not limited to any particular point, and in fact is often all over. When the foreign body cannot be directly seen, but the history and objective apjiearances of perforation point to its being present in the eye, a tenderness on jtressure at some particular point over the sclera indicates its position in not a few cases. A point, too, of diagnostic importance in a doubtful case is the existence of an amount of inflammation disproijortionate to the severity of the trauma alone. This should always give rise to the susjncion that something is lodged in the eye. Attention must also be |)aid to the nature of the visual dis- turbances. Apart from the defects corresponding to the visible optical changes which alone exist in the case of bodies lodged in the anterior part of the eye, there may usually be made out other defects as well when the vitreous chamber or coats at the back of the eye are the site of the foreign body. These are of two kinds, positive scotomata and restrictions in the field of vision. The scotoma may be either the projection externally of the shadow thrown on the retina by the foreign body, or it may be due to a lesion in the fundus of the eye. Restriction in the field of vision is due either to the presence of blood or purulent exudation in the vitreous, or to detachment of the retina. This restriction in the iield of vision is one of the most valuable points in the diagnosis when it is otherwise difficult on account of opacity of the lens. The scotoma, too, may diminish in size, from absorjttion of extravasated blood, or increase, as the subsequent exudation becomes denser and more copious. Tventment. — The successful removal of foreign bodies from the vitreous and back of the eye was, until comparatively recently, of so excessively rare occurrence that practically the chances of an operation undertaken for that ]juri)0se being successful were nil. Now, by the aid of the magnet, a good many eyes can be saved which must jireviously have Ijeen lost. By this means only particles of iron and steel can, under favourable circum- stajices, be removed, while with regard to other bodies we are not better situated than before. Iron and steel particles form, however, a large proportion of all the cases met with. IN THE POSTERIOR SECTION OF THE EYE. 347 In cases of portions of non-magnetisal )le metals in the vitreous, an immediate operation is hardly justitial)le, as the chance, small as it is, of the foreign body being encapsuled, or leading to relatively little irritation, is still greater than that of one's being able successfully to remove it. The removal may be attempted in the secondary stage, however, when the patient has been prepared for the alternative treatment of evisceration or enu- cleation of the eye should the attempt fail, as it is likely to do. In any case, the incision should be made radially and not circularly in the sclera, and at the lower part, except where a point of marked tenderness exists in some other situation, when that point should be selected instead. Bodies fixed in the coats of the eye may occasionally l)e seized with forceps and with- drawn, and a relatively good result be obtained. Unfortunately the advisability of performing any operation for the removal of foreign bodies from the eye is often question- able, on account of the risk which is then run from sympathetic inflammation occurring sooner or later in the other eye. When the injury has been so severe as to destroy vision from the first, there can be no hesitation about removing an eye in which a foi'eign body is lodged. If this can be done within the first week, evisceration is the most satisfactory operation — if later on, enucleation. A difficulty in deciding arises in most of the cases where some vision is retained, and here much will depend on the course taken by the inriammation. This is esjiecially the case where the foreign body is a shot pellet. When the pene- tration has taken place through the sclera, and the wound made in it is small, there is not much danger of any septic matter having been introduced at the same time, so that it is generally advisable to make an attempt to kee}) the eye. Where the exudation can be made out to be extending, removal of the eye should be advised ; but an attempt may first be made to extract the foreign body, if the patient thoroughly understands the risk Avhich he still runs, even if this should be successful. Other points in this connection are discussed in the next chapter. CHAPTER XII. SYMPATHETIC OPHTHALMITIS. A GREAT number of affections of the eye are, or are supposed to be, in some measure caused by intiammatory conditions which have pre-existed in the other eye, and are consequently looked ui)on as sympathetic. The disease which is generally spoken of as sjTiipathetic ophthalmitis is an intlammation of the uveal tract, more especially of its ciliary portion, which comes on — rarely sooner than three weeks, and often much longer — after some injury or affection of the other eye, which has been followed by more or less destructive inflammation in it. There is nothing absolutely characteristic about a s}niipa- thetic ophthalmitis ; it may be acute, but it is more often dis- tinctly chronic. It may be mild from the first, or of a decidedly malignant type, and it may be recovered from, or lead to con- siderable or to complete blindness. An inflammation of the eye which is sympathetic in this sense is usually very protracted. It is either altogether painless, or accompanied by but little pain. In connection with this subject it is convenient and cus- tomary to use the following terms. The eye first affected is called the cxcitimj eye, or shortly the exciter ; the other, the si/mjMithisin;/ eye, or the sympatlii:ossihility, but extremely little prohahility, of the remainim/ eye, if it has previously been sound, becomimj affected, while after two months it may he considered absolutely safe. These clinical facts are imi)ortant, and have to be ke])t in view. They at all events make the decision, of what should be done, easy in the case of blind eyes. When, for instance, a recent injury of such a nature as would be likely to introduce sei)tic matter into the eye has at the same time caused irrepar- able blindness, there can be no question as to the advisability of enucleation. Sufl'ering will be prevented, and any risk of a much greater misfortune will be obviated by resorting to this measure. It should therefore be urged upon the patient as strongly as possible. A similar proceeding is indicated where a })reviously injured and sightless eye has become irritable and tender to pressure. Only if the irritation is due to increased tension — a secondary glaucoma — is the necessity for interference of this nature uncalled for. Injured eyes are, however, far from being always completely blind. In many instances, indeed, a useful degree of vision may still remain, and yet they cannot be looked upon, it may be. as safe in regard to the risk in question. Here it is that the difficulty of determining upon the adoption of the prophylactic effect of enucleation asserts itself. The difficulty is not so great, no doubt, in the case of recent injuries, because at all events the proi)hylaxi3 is certain. Even if the surgeon should consider it necessary to remove such an eye, it may not be easy to obtain the patient's consent. In other cases, however, in coming to a decision as to whether a not altogether blind eye, which has been exceedingly irritable for some weeks after injury, or has again become inflamed after a longer period of quiescence, should be sacrificed in the in- terest of the other, one has to face the possibility of this measure, if adopted, not succeeding in preventing sympathetic inflammation. Under such circumstances, if the second eye should eventually be lost by irido-cyclitis, one might have to blame one's-self for having removed the only chance of some remaining sight. With regard to the inflammation in the sympathising eye, which only comes on within a short time after excision of the EVISCERATION. 355 exciting eye, the question naturally arises, Is it as severe and intractable as that which is met with where the exciting eye has not been removed 1 The answer to this is, that whilst on the average it is less severe and more amenable to treatment, experience has shown that it may be quite as disastrous. The same may be said of the effect of enucleation of the exciting eye, when undertaken after sympathetic inflammation has begun. There is then, at all events, a chance that the secondary process may be checked at an earlier stage than would be the case if the source of excitation were allowed to remain. What applies to enucleation as a proi^hylactic measure applies equally to evisceration. A proj^erly performed evisceration is capable, under practically the same restrictions, of i)reventing the occurrence of sympathetic ophthalmitis. It is, however, essential that the evisceration should be complete, and that absolutely no trace of any other parts of the eye should be left within the scleral shell. Section of the optic nerve without removal of, and with ex- cision of, a piece of the nerve — neurotomy and neurectomy — have also been advocated, but are undoubtedly inferior pro- phylactic measures. If the prophylactic treatment may offer difficulties, the difficulties in connection with the treatment of an actual sym- pathetic irido-cyclitis are still greater. The first thing to do, as soon as ever any circumcorneal injection or loss of gloss of iris surface shows itself in the second eye, is to use atropine freely until the pupil is widely dilated. The tendency for the pupil to become entirely blocked by exudation is so great, that every effort must be directed to keeping it as wide as possible. If this should cause tension, I believe the best treatment, under the circumstances, is to i^erform sclerotomy. This is preferably done by means of a jjeripheral incision with a triangular-shaped keratome. Iridectomy should not be done at first, but the sclerotomy, which need not be very large, may be repeated several times.'' On the ces.sation of the inflammation, which usually lasts for months, and after the eye has been quiet for some weeks, a large iridectomy should be made. Even then there is a great chance of the aperture made becoming occluded. When this happens, and after the eye comes to rest, if it still retains some vision, even if it merely be perception of light, the best thing to do is to remove the lens through an incision, as if for cataract extraction, made along the corneo-scleral margin. Even this does not always result in a permanently open pupil. 356 .SYMPATHETIC OPHTHALMITIS. It may then be necessary, after a further period of inflamma- tion, followed by quiescence, to perform" an iridotomy, cutting through the matted-down iris and organised exudation with a sharp knife or scissors made for the pur^iose. In this way I have sometimes succeeded in restoring a useful amount of vision after a long period of practical blindness. In many cases degenerative changes have sui)ervened, following ui)on continued intlanunation, before this amount of interference is possible. Medical treatment is of little use. Mercurial inunction should be tried, and the pain, when it is present, may be allayed by hot sponging and antipyrin. Evisceration of the globe. — The instruments I'cquired for this o})cration are a si)eculum and fixation forceps, a Graefe's knife, a pair of scissors, and a blunt Volkmann's spoon. The conjunctiva is first undermined for a short distance all round the cornea. The anterior chamber is then trans- fixed on a level with the horizontal meridian of the cornea, and a section made which completely se})arates the lower portion of the cornea from the sclera along the junction between them. The flap of cornea thus formed is then seized with the forceps, and the rest of the cornea separated with the scissors. With a special form of shovel scoop (Fig. 149) the whole contents of the globe can noAv be evacuated. This must be done thoroughly, so that nothing is left but the sclera. When the bleeding which this causes has been stopped by means of pledgets of cotton-wool introduced into the cavity, the edges of the sclera are brought together with three vertically laid catgut sutures. The conjunctiva is then stitched up in the same way, the sutures being, however, laid horizontally. This operation is often followed by considei'- able (edematous infiltration of the tissues, and pain, which may last from twenty-four to forty- eight hours. I have not found that the introduction of horse-hair or catgut as a drain has modified the severity of the infiltration, although it has been recommended for this pur})0se. The stump left, though admitting of a better move- ment in an artificial eye than results from enucleation of the Fig. 149.— Evisceration scoop. ENUCLEATION OF THE EYEBALL. 357 eye altogether, is yet not so markedly better in this respect as might be supposed from the appearance shortly after operation. A very great degree of shrinking takes place in the course of time, so that the pad on which the muscles act is greatly reduced in size. To obviate this defect, a modification of the operation was recom- mended by Mules, which consists in intro- ducing a glass ball into the scleral cavity and uniting the conjunctiva over this. My own experience of Mules' operation has not been particularly encouraging. In a great many cases the glass ball seems to be expelled sooner or later by ulceration of the overlying tissues ; but the eventual result in such cases does not appear to be worse than if the attempt had not been made, although the patient is neces- sarily subjected to a somewhat prolonged treatment. When the operation does succeed, the effect, so far as the movements of the artificial eye — which rests on this artificial stump — go, could hardly be more beautiful. Enucleation of the eyeball. — The instru- ments required for enucleation are a speculum, fixation forceps, strabismus hook, and a pair of strong scissors curved on the flat. Ansesthetics should generally be used, though the pain may be to a great extent mitigated by the free use of cocaine during the operation. The conjunctiva immediately surrounding the cornea is first incised. This is best done by catching hold of a portion of the upper part W'ith the forceps, snipi)ing through it with the scissors, and then passing one blade behind, allowing it to glide beneath the conjunctiva to one side of the cornea, while the other blade remains external to the conjunctiva. In this way one or two cuts with the scissors will suffice to complete the division of one-half of the conjunctiva surrounding the cornea, while the other half may be divided by using the l)lades in the same way along the other side, after having begun again at the })oint above, where the first perforation was made. This having been done, the capsule of Tenon is opened by a more free use ot the scissors at the lower portion, just over the inferior rectus. Fig. 150. — Instru- ment for inserting glass globe into eviscerated eve- Lall. 358 SYxAIPATHETIC Ol'HTHALMITIS. The strabismus hook is tlien passed under the inferior rectus, which is divided close to its insertion. The hook may now be swei>t in succession round each of the recti muscles, and their insertion severed from the globe iu the same way. After divid- ing the insertion of the superior rectus, the hook should be passed deeper, so as to hook up the superior o])lique, which must also be divided in the same way. The branches of the speculum are then separated as much as jjossible, and the eye allowed to protrude. The scissors must next be passed in between the capsule and the globe to the back of the eye, the blades being kept closed until the points are felt to touch the optic nerve. They are then opened and pushed a little farther, so as to cause the blades to pass one on either side of the nerve, which is cut across with a firm snip. The eye can now be drawn forwards, as it is only held by a few bands of connective tissue, which have to be snipped across to complete its removal. The bleeding is readily stop})ed with pledgets of cotton-wool. The proper arresting of the bleeding, as well as careful antiseptic treat- ment throughout, should be attended to, as these points are of imi)ortance in ensuring the speedy healing of the wound left in the orbit. A tight bandage should be applied and kept on for four or five hours, so as to prevent any infiltration of the tissues with blood. Afterwards nothing is required but attention to the cleanliness of the wound by frequent syringing or bathing with corrosive sublimate solution. It is a good plan, Frr,. 151. — Eiuieleation scissor.- ENUCLEATION OF THE EYEBALL. 359 too, to smear a little lard along the edges of the lids at night, so as to prevent any retention of the secretions. An artificial eye should not be worn for about two months. The eye, when worn, should be removed every night, and kejjt in water containing a little antiseptic. When it becomes corroded, it should be repolished, and at any time any irritation which it may produce should be taken by the patient as a warning that its use should be left off for some time. There is a great tendency amongst the wearers of artificial eyes to have them too big. They do not, in looking at themselves in the glass, appreciate the staring appearance of such an eye. It is better to have one of such a size that the lid droops slightly over it, as compared with the other eye. Such an eye is not only less likely to set up irritation, but is also much more deceptive. Operations are sometimes required to render the socket better fitted to lodge an artificial eye. No definite rules can be laid down for such operations. The surgeon must be guided by the conditions presented by each individual case. Sometimes, owing to the tendency to drooping of the lower lid, it is necessary to raise it by uniting the upper and lower lids at the outer can thus. CHAPTER XIII. GLAUCOMA. The chief objective signs of glaucoma are — (1) Increased intra- ocular tension; (2) dilatation and immobility of the pupil; (3) haziness of the cornea ; (4) shallowness of the anterior chamber ; (5) enlargement of episcleral veins ; (6) excavation of papilla ; (7) visible pulsation of the retinal artery. At the same time the following subjective symi)toms are met with — (1) Defective central vision ; (2) more or less characteristic limitation of the field of vision ; (3) photopsia ; (4) anaesthesia of the cornea ; (5) pain. A marked and imjjortant characteristic of (jlaucoma is the intermittent nature of both objective and subjective symptoms. This intermittency is met with at all stages of the disease, and even persists when the eye is totally blind, subjective light sensations and pain coming on every now and then, and at other times being wholly absent. From a clinical point of view the following forms of glaucoma should be distinguished : — A. Primary glaucoma. 1. Congestive glaucoma. (a) Acute. (/3) Chronic. 2. Non-congestive glaucoma. B. Secondary glaucoma. We may distinguish three stages of the disease, in whatever form it is met with — (1) The threatened stage, in which the premonitory symptoms to be shortly described assert themselves ; (2) the confirmed stage, in which the disease has led to defective vision, which gradually increases until (3) the glaucoma is said to be absolute, or has resulted in complete destruction of vision. In many cases degenerative changes have already begun by the time the absolute stage is reached ; in all cases such changes eventually make their apjiearance. Primary glaucoma is essentially a disease of advanced life ; PRIMARY GLAUCOMA. 361 it is rarely met with before the age of forty, and increases in frequency with age. It is most common for both eyes to be subject to attacks of glaucoma. In a certain proportion of cases of glaucoma, variously estimated at from one-third to three-fourths of all cases, the actual outbreak of the disease is preceded by premonitory symptoms, more or less marked, and occurring at, as well as extending over, longer or shorter periods of time. What dis- tinguishes the disease in this stage from that in which it may be said to be fully developed, is that during the intervals between the occurrence of these symi)toms the functions of the eye are to all appearance normal. The 2i'>'e'nionitory symjitoms are obscurations of vision and the appearance of haloes round lights. The vision appears more or less misty and veiled, this being especially noticeable for objects which are not very strongly illuminated. At the same time, if the flame of a candle or gas jet be looked at against a dark background, it is seen to be surrounded by a colourless space, which is encircled by a coloured halo, the intensity of which differs in difierent cases, as well as at different times in the same case. These symptoms usually come on after some mental or physical fatigue, e.g., a sleepless night, or prolonged fasting. They disappear after a meal, and more constantly after sleep, and can also almost invariably be cut short by the use of a miotic. The intervals between such attacks are very variable, often amount- ing to months or years, but usually having a tendency to become shorter and shorter, until the glaucoma suddenly or gradually passes from the premonitory to the confirmed stage. Premonitory symptoms appear to be on the whole more common the younger the individual attacked with glaucoma. The cloudy vision varies in amount, but may be very disagree- able to the patient at a time when he is found on examination to have full visual acuity, although, as a rule, it is accompanied by some diminution in the acuteness of vision. The halo seen is always perfectly circular. Its apparent size increases, and the breadth of each coloured ring becomes greater the farther the light is from the eye. During the premonitory attack the tension of the eye is always increased, and there is more or less diffuse ojiacity of the cornea. Sometimes, however, the opacity is so slight as to be barely noticeable on oblique illumination. There can be little doubt that the haloes are due to the diffraction of the rays passing into the eyes, and this diffraction jtrobably mainly takes place in the cornea as the result of the opacity. 362 GLAUCOMA. The obscurations of vision are also to a great extent, though probably not entirely, due to the opacity of the cornea. The vision of haloes round lights is not altogether patho- gnomonic of glaucoma. It is met with, for instance, in cases of conjunctivitis, owing to the difi'raction caused by the conjunctival secretion lying in front of the cornea. In such cases the haloes disappear on rubbing the eye. A good many people, too, with normal eyes see them, especially if the pupil is dilated. They are probably, hoAvever, rarely seen of the same intensity as in glaucoma, so that when suddenly observed they should awaken suspicion. If an ophthalmoscopic examination be made at the time when the premonitory symptoms are complained of, there is sometimes seen to be a spontaneous pulsation of the arteries on the disc. This appearance disappears with the disappearance of the sub- jective symptoms, and of the increase of intra-ocular tension. The same pulsation may be produced by external pressure on the eye ; and in cases where the intra-ocular tension is increased, and yet the pulsation not visible, it may often readily be elicited by slight pressure on the eye with the finger. The increased intra-ocular tension is not always present at the time of examination of an eye affected with glaucoma. During an attack, when the cornea is hazy, the vision more interfered with than usual, and the patient suffering pain in the eye and over other parts in the region of distribution of the fifth nerve, increased tension is rarely if ever absent. In the non-congestive form of glaucoma it is usually less constant and less pronounced than in that in which there exists an evident congestion. The degree of intra-ocular tension is subject to considerable differ- ences physiologically, some eyes being distinctly harder than others, and for this reason it is not by any means easy to feel sure in any particular case that the tension is higher than normal. If, for other reasons, one is led to suspect a possibly increased tension in one eye only, it should be comjiared carefully with the other, which affords the best standard for judging of the tension in the doubtful one. Various instruments, called tonometers, have been devised for the })uri)ose of measuring the intra-ocular tension, but none of these appear to afford any more delicate or more trustworthy information than is given by palpation with the ends of the fingers. Two ways of making such palpation may be employed. The point of each forefinger may l)e placed on the closed eye, and alternately pressed gently upon the globe through the upper Hd ; DILATATION OF THE PUPIL. 363 or the forefinger of one hand may be applied directly to the con- junctiva covering the sclera when the eye is directed upwards, and a series of slight taps given, without at any time removing the finger altogether from contact with the eye. In either of these ways the resistance of the eye can be determined with considerable delicacy, so that a little practice suffices to enable one to gauge the relative hardness of two eyes tested at the same time. It is more diflicult to acquire the power of estimating the amount of change in tension. It is customary to distinguish three degrees of increased hardness. These three degrees, which were pointed out by Bowman as practically distinguishable, are — (1) A marked increase, as compared with the normal, or T+1 according to Bowman's notation ; (2) a great increase, but one in which, to the palpating finger-points, the eyeball still admits of some dimpling, T + 2 ; and (3) that degree of tension upon which little impression is made, even by firm pressure on the eye, T + 3. A doubtful increase may be noted as T + ? While such a division is extremely practical and universally adopted, it must not be supposed that any hard-and-fast line exists between the difterent degrees of increased tension ; thus it is not an uncommon thing to find a particular degree of tension denoted by one examiner as T-fl, and by another, equally practised, as T -I- 2. This is, however, a matter of little importance, as under such circumstances there is no doubt as to the abnormal degree of tension. The more important cases are those in which there may be a difference of opinion as to whether any increase in tension exists at all. Dilatation of the -pupil, along with more or less complete im- mobility, is very constant in glaucoma. The dilatation is not always regular, and the pupil is frequently oval or egg-shaped, owing to greater dilatation at some parts than at others. This is a point of some importance in connection with the differential diagnosis between simple, non-congestive glaucoma and optic atrophy. The eye presents at the same time a muddy api)ear- ance, and the pupil frequently has that greyish-green colour which gave rise to the name of glaucoma. This is due to the reflection of light from the surface of the lens, modified to some extent by the haze of the cornea, and apparent on account of the dilatation of the pupil. The pupil may be got to contract liy the use of the eserine, and to dilate still further by atropine, in most cases where the iris tissue has not undergone an atrophic change — most readily therefore, on the whole, in early cases. Tlie haziness of the cornea is a constant appearance during the period of exacerbation in all congestive cases. In chronic non- :\6i GLAUCOMA. congostive cases it is often absent, or present only to a very slight extent, though at times, when the tension is high, it may even in such cases be sufficiently evident. The peculiarity of the corneal haze in glaucoma is that it is continuous and most intense toward the centre of the cornea. It is always accom- panied by a dull and somewhat stippled apj)earance of the sur- face. A characteristic, too, is the disappearance of the haze immediately on, or very soon after, the return of the tension to the normal. Shallowness of tlie anterior chamber is almost invariably met with to a greater or less extent, though sometimes the opposite condition occurs. In most cases where glaucoma occurs in young individuals, the anterior chamber, instead of being shallow, is abnormally deep, owing to the retention of liquid in the anterior chamber. This is also the case in some forms of secondary glaucoma. Enlargement of e2nscleral veins occurs in most cases which have existed for some time, more especially in the congestive form of the disease, though this change is rarely absent alto- gether, even in cases of simple glaucoma. In acute congestive glaucoma we meet with hypenemia and chemosis instead, as the result of the sudden disturbance in the venous circulation within the eye, which, when long continued, is the cause of the disten- sion of the external veins. Excavation of the papilla — the so-called glaucoma cupping — is met with sooner or later in all cases of glaucoma, but the extent of the cupping does not stand in any very close rela- tion to the degree of visual defect. When fully developed, the papilla in glaucoma i)resents the following appearances on oph- thalmoscopic examination. The vessels are ijushed to the inner or nasal side, and appear to bend .sharply round the margin of the disc in this situation, without therefore coursing over any portion of normal [)apilla, the veins being at the same time fre- quently distended and the arteries small. The rest of the papilla IJresents a greyish-blue appearance, which is seldom uniform, being more frequently specked with white, especially at the centre. There is besides, when the retinal vessels are not very greatly atrophied, a blurred appearance of vessels to be seen in this bluish area. Surrounding the papilla there is almost in- variably a whitish-yellow ring, the breadth of which varies con- siderably in different cases, but which seldom measures more than one-fourth or one-third the breadth of the papilla. The l)readth is as a rule uniform throughout. Even a slight degree of excavation can be readily diagnosed, EXCAVATION OF THE PAPILLA. 365 by the indirect method of ophthahnoscopic examination, by ob- serving the parallax caused by moving the lens from side to side. The edges of the papilla are in this way seen to ajj^tarently slide back and forwards over the central part. From this Ave know that the aerial image of the borders of the disc lies nearer the observer than that of the centre of the disc, and consequently is that of an object whose distance behind the cornea is less. The actual depth of the excavation can be approximately determined by estimating the refraction by direct ophthalmoscopic examina- FlG. l.'rj. Finiii a case of glaucoma, .showing vessels pushed to na.sal side of disc, over th(» margin of which they suddeuly dip : also the halo of degeneration round the disc and the cupping with the central vessels out of focus (typical glaucomatous excavation of optic nerve). tion of the margin and of the centre or deepest part of the cup, and allowing three dioptres to every millimetre. There is little difficulty, as a rule, in diagnosing a glaucoma excavation when fully formed, but the less marked changes which occur at first are by no means always entirely characteristic, and may be confounded with physiological excavation, and also with that excavation which is met with in atro})hy of the nerve. When the visual defect is inappreciable, the glaucoma excavation may be taken for a physiological one ; while, on the other hand, in cases where, from some cause or other, vision is at the same 366 GLAUCOMA. time impaired, one is apt to ascribe undue importance to an existing physiological excavation. The i)liysiological excavation is white, and never involves very much of the nasal part of the disc, over which the vessels can consequently always be seen to course. When large, it may extend over a large part, or even the whole, of the temporal half. The vessels can generally be followed down the side of the excavation, which is funnel- shaped, and not steej), as that met with in glaucoma. In cases temporal i\''":s!^ / Wi-^ 'i'<\'m\ '^i''' '11 nasal Fig. 153. — Longitudinal .section tlirougli papilla with glaucomatous excavation, .showing cau.se of ophthalmoscopic appearances. — After FucHS. of uncertainty we have to fall back upon the subjective symptoms, in order to avoid mistakes. The greatest difficulty is experi- enced in simple glaucoma sometimes, when the excavation is not very characteristic, as the subjective symptoms are hardly dis- tinguishable from those accompanying atroj^hy. The ati'ophic excavation is shallow, and as a rule occupies the whole disc. The vessels never bend sharply over the margin of the disc, and can be seen, more or less out of focus, continually from the point PULSATION OF THE RETINAL ARTERIES. 367 or points at which they emerge from the nerve. The appear- ances, which of themselves would tend to render glaucoma the probable cause of the excavation, should it be slight and not very typical, are the crowding of the vessels to the nasal side of the disc, and the yellowish ring surrounding the disc. The straight dipping of all the vessels, which is met with in a later stage, is quite characteristic. A sjJOiitaneous pulsation of the retinal arteries on the cupi)ed disc is almost a certain proof of the existence of glaucoma. Such visible arterial pulsation is very rare under other circum- stances. It is due to some resistance to the flow of blood through the retinal arteries, so that the current is only com- plete during a systole. The impediment is mainly, no doubt, the result of increased intra-ocular pressure on the vessels, but it Fig. 154. — Diagrammatic representation of the different forms of excavation. A, Pliysiological ; B, atrophic ; C, glaucomatous. — After FucHS. is possible that, in many cases at least, it is due in some measure to an active spasmodic constriction of these vessels themselves. It disappears almost invariably after iridectomy, and cases where this pulsation is visible are such as are most likely to be benefited by operation. The cause of the excavation of the papilla in glaucoma is the gradual recession of the lamina cribrosa. This structure is unable to resist for long the increased pressure to which it is subjected, so that after frequent attacks of abnormal tension the end of the nerve becomes hollowed out. The excavation of the papilla depends in all ^jrobability less on the degree than on the duration of the increased tension. The yellow ring is generally believed to be due to some atroi>hy of the choroid caused by pressure or distension as the lamina cribrosa recedes. 368 GLAUCOMA. Tlie (iri(te}iess of vision begins to diminish and become ]»er- manently impaired as soon as the ghiucoma lias passed from the premonitory to the fully developed stage. Dm'ing the existence of premonitory symptoms more or less diminution of vision takes place, l)ut this is recovered from as soon as the attack passes off. Even in cases which have advanced to true glaucoma we may usually distinguish between a permanent and a tran- sitory element in the blindness. During each exacerbation which occurs in a case of congestive glaucoma the vision is worse than before ; after the acute symptoms subside there is a gradual recovery to a certain extent, which, however, does not as a rule lead to a restoration of the same degree of acuteness which existed before the attack. Each attack, therefore, leaves vision more impaired than before, until it is eventually lost altogether. There is a very great difference in the rapidity with which complete destruction of vision takes place, a difference which de})ends on the nature and severity as well as the frequency of the acute attacks, and also upon the continuance of the increased tension. In the most acute cases, where the symptoms of con- gestion are excessive, vision may be altogether lost in a few hours. To such cases the name f/laucoma fulminans has been given ; while, on the other hand, chronic cases, and more })ar- ticularly chronic non-congestive cases, may not lead to the com- plete loss of vision until after the lapse of many years. Restriction of the field of vision occurs at the same time as the defect in the acuteness of central vision. There is no absolute constancy in the manner in which the field of vision is invaded, but most frequently one finds the nasal portion abolished to a greater extent at first than other portions of the field, and not infrequently this portion alone can be demon- strated to be defective. Wherever the restriction is, it is generally continuous ; that is to say, there are not, as a rule, scotomata, but if one part of the retina has lost its function, that of the parts more peripheral to it in the same dii'ection is mostly also abolished. The blind portion of the field of vision is bordered by an amblyopic area in which colour vision is either absent or defective, but there is not the same recession of the boundaries for colour vision as is met with in atrophy of the optic nerve. The limit at which the different colours are recognisable is usually nuich the same for all, and only slightly narrower than the corresponding boundary for uncoloured impressions, while even in cases where the limitation is very great there still remains colour perception. It is the rule for RESTRICTION OF THE FIELD OF VISION. 369 this greater restriction to the nasal side of the field to progress and eventually involve the centre before complete blindness sets in, so that at an advanced stage of the disease only an eccentric portion of the temporal side remains. The preponderance of the nasal invasion of the field appears to be more common in chronic than in acute cases of glaucoma. The manner of restriction next most frequently met with is the concentric restriction, where there is a tolerably proportionate interference with the function of all parts of the periphery of the retina. It is very rare indeed to find the restriction most marked outwards. Fig. 155. — Typical defect of field of vision, from a case of glaucoma. In not a few cases the central vision is markedly diminished without any easily demonstrable defect in the field. If the glaucoma field be taken for a white object 3 mm. in diameter at 2 metres from the eye, and therefore for an object subtending a very small visual angle, there is almost invariably to be found a very characteristic form of restriction. The shape of the field is by no means always the same in all cases, but the defective area is always found to extend right up to the blind spot in one direction or another. The blind area corresponding to the entrance of the optic nerve is therefore continuous in some direction with the defect in the field caused by the glaucoma, while in other directions it is found to have its normal boundaries. 24 370 GLAUCOMA. This syniptoin, first described by Bjerrum, is the earliest recoguisable cliange in most cases of glaucoma. The jxjculiar form of restriction described is not met with in any other disease. Phofopsia, or the subjective sensation of light, is not an invariable symptom, and is besides a very inconstant one in any particular case of glaucoma. It is seldom very marked, but is sometimes present to a painful extent, and often persists even after the disease has led to complete blindness. Even at this time it is a variable symi)tom, being only experienced during the attacks which give rise to pain and increased tension. It is a very common thing to hear patients who are absolutely blind Fig. 156. — Fields of vision in glaucoma, as taken with different-sizerl objects. Right eye, V=/^ : Field for ordinary perimeter test (Wtj) shaded area : for 3 mm. object at 1 metre (rtAio) dotted area : for 1 mm. object at 1 metre (rii'tro) white area. L''/t eye, V=§: Field for ^^, shaded area: for j^^i^, dotted area: for luVo' white area. — From a case of Dr. Sinclair's. from glaucoma declare that they can see light, and to find on examination no cause for this other than a mechanical one. Ancesthesia of the cornea is met with in almost all cases of confirmed glaucoma. The anaesthesia is not as a rule equally marked over the whole extent of the cornea, but it is seldom that on careful exploration some point or points of diminished sensi- bility are not to be found. The test is best made by touching the cornea with a small feather or camel's-hair brush. The cause of this anaesthesia is probably explained by pressure on or separation of the nerve filaments in the cornea as a result of the cedema, which is the anatomical change giving rise to the haze. Pain, varying in amount from a disagreeable sensation of fulness and dragging in the eye, to the most acute neuralgia ACUTE AND SUBACUTE ATTACKS. 371 over the whole region supplied by the fifth nerve, is a symptom which always marks at anyrate the exacerbations in congestive glaucoma, and which in many cases is pretty constant. Unfor- tunately those who suffer from glaucoma do not, as a rule, get rid of the pain after the glaucoma has become absolute. In very acute cases the irritation of the fifth nerve brings on somewhat alarming general symptoms, — feverishness, sickness, and vomiting, — which may be so severe as to distract attention from the local mischief. The most common form in which glaucoma presents itself is as subacute attacks, following each other at intervals, the first beginning as a rule after some premonitory symptoms have previously been observed. After each attack of this nature a partial recovery of vision takes place, but the ultimate amount of vision is almost always less than it was before, the field more restricted, and the excavation of the papilla more marked. The exacerbations become eventually more frequent and permanent, and the recovery after each attack is less complete, until eventu- ally the chronic congestive type of the disease is fully develojjed, and presents all, or most of, the objective and subjective symp- toms already described. Even after a long continuance of the simple non-congestive form of the disease, it is possible for acute symptoms to develop all at once. As a rule, however, cases of glaucoma simplex retain their character to the end. Probably many years may pass before the excavation of the nerve becomes complete ; but when the case is first seen, there is generally marked cupping, although there may be no external evidence of any impeded circulation. In a severe acute attack the circulatory disturbance leads not only to rapid and extreme increase of intra-ocular tension, but also to exudations into the external tissues of the eye, giving rise to chemosis, and even redness and swelling of the lids. The corneal haze, too, is very great, the pupil dilated and absolutely immobile, while the severity of the attack is evidenced by the photophobia, lachrymation, pain, vomiting, and general disturb- ance to which it gives rise. The vision, too, is either rapidly altogether lost or very much impaired. A subacute attack, on the other hand, is characterised by a less sudden deterioration as well as by a greater subsequent improvement of vision. Acute or subacute attacks of glaucoma come on in eyes pre- disposed to the disease after the occurrence of anything which may be supposed to lead to a venous stasis in the uveal tract, either directly or owing to diminished arterial tension. Fits of mental depression and sleeplessness are thus likely to be followed 372 GLAUCOMA. by <^liUicoina, and tliis is also the case where there is a weakness of the heart's action, as during convalescence from illness. In short, any debilitating condition may be followed by glaucoma. ITnder such circumstances the impil is apt to become dilated. This condition is of itself likely to favour the outbreak of glaucoma when the predisposition exists. Thus one sees every now and then an attack follow the use of atropine. Even liomatro])ine and cocaine have been observed to ])roduce the same effect. On the other hand, a natural or induced contrac- tion of the pu})il, when this can take })lace, often cuts short an attack. This is no doubt one reason why sleep is found to be so beneficial in the early stage of the disease. As to the pre- dUpodtion, it is seldom, unless premonitory symptoms have been complained of, that one can be alive to its existence. Diar/nosis. — There are two reasons why an early diagnosis of glaucoma is desirable. On the one hand, it enables one to ti'eat the disease at a stage when, according to the severity of the glaucoma, little, or comparatively little, permanent damage has been done to sight ; and, on the other hand, at which, altogether independent of this, it is most amenable to treatment. Except in cases of the more acute congestive variety of glaucoma, the result of successful interference is only a checking of the disease, without restoration of what has been lost. Whilst, then, these considerations suffice to show the import- ance of making a diagnosis, it must be admitted that the diag- nosis is by no means always easy. In acute congestive attacks, the more or less marked sym})toms of general disturbance are apt to take one's attention from their real point of origin. In non-congestive glaucoma, on the other hand, the disease is usually of a slow, insidious nature, and as such is apt to escape observation. Indeed, there are some cases of the so-called "simple" variety of glaucoma which even the experienced ophthalmic surgeon may have great difficulty in distinguishing from cases of atrophy of the optic nerve. The general practitioner, who has not devoted very consider- able attention to the clinical study of eye diseases, could hardly be expected always to diagnose glaucoma. He should, however, unquestionably know of the existence of such a disease, and, in the absence of any particular familiarity with it, it would be well if he erred rather on the side of too great than of too little suspicion of its presence, in cases the exact nature of which he did not understand. Thus, especially in elderly or old people who may complain to him of failing sight, he should always inquire as to the particular subjective symptoms which may DIAGNOSIS. 373 characterise that failure. More j)articu]arly .should he ascertain if there appears to be any more or less marked degree of inter- mittency in it. Are there, for instance, periods of greater obscuration, succeeded by longer periods of relatively better vision ? Further, is there a more or less constant haze or smoky veil seen in front of the eyes, which occasionally a})pears to be denser than at other times 1 Temporary obscurations, clouded or misty vision, and the appearance of coloured haloes or rings round lights, are suggestive of glaucoma, particularly in old people, and should awaken suspicion. It must be remembered, too, that these symptoms are not always very marked in the "simple " cases of the disease. Therefore, in the presence of failing sight, which is only, it may be, subject to periodic variations, a very easy examination should be undertaken. This consists of a rough test of the scope of the field of vision in the manner described in Chap. II. Any restriction, particularly if it involves the lower or inner I)ortions of the field, should awaken the suspicion of glaucoma. Great failure of vision, without any restriction in the scope of the field of vision, is rare in glaucoma. Under the circum- stances, then, a free, unrestricted field of vision should be re- assuring where there might otherwise have appeared to be any reason to suspect glaucoma. On the other hand, the opposite condition, namely, restriction of the field with comparatively little loss of vision, should strengthen such suspicion. I have referred, so far, to subjective symptoms and subjective examination in this relation, because experience has taught me that fewer mistakes are liable to be made by the comparatively speaking inexperienced, than when attention is directed more to 'real or imaginary objective signs. Such objective signs there are, as we have seen. Indeed, the diagnosis cannot properly be confirmed without giving attention to them as well. In the order of their importance these signs are : excavation or " cup- ping " of the optic disc, increased intra-ocular tension, haziness of the cornea, semi-dilatation of the pupil, and enlargement of the episcleral veins. Now, with regard to these, it may be said that if the general l)ractitioner, who so comparatively seldom meets with a case of glaucoma at all, and who has so many other diseases to know about and to treat, is to wait till he can satisfy himself of the existence of a " glaucoma cup " before feeling i-easonably satisfied that he has to do with a case of this disease, he will, generally speaking, fail to act in the best interests of his patient. There are, in fact, some cases in which a certain degree of doubt may 374 GLAUCOMA. exist as to wliether a i)articular excavation is essentially "glan- coniatous " or not. Then, as to increased tension, it is often, in the more chronic cases, difficult to feel satisfied that there is any abnormal degree of tension present. Like other signs of glau- coma, the increased tension is to a great extent an intermittent one. Nevertheless it is one of the most important signs to which to direct one's attention in the less frequent variety of congestive glaucoma, with i)ain and corneal haze. I have found that the cases of glaucoma most liable to be overlooked by the i)atient's ordinary medical attendant are the chronic non - congestive ones, and the very acute congestive attacks associated with marked general disturbance. The first class of case, especially when occurring, as it usually does, in an old person, is apt, in the absence of a properly directed sub- jective examination, to be mistaken for cataract. The greyish rertection which comes from the lens in old people gives rise, when the pupil is more or less dilated, to the idea that there is an actual loss of transparency of the lens. The i)atient is then told that he has cataract, and that nothing can be done until he has become blind. Thus the ojjportunity for arresting the disease is lost. A knowledge of the existence of such a disease as glaucoma, and of the various forms which it may assume, and a simple subjective examination on the lines above referred to, would strengthen the suspicion that a mistake in diagnosis might be possible, even should the ophthalmoscopic signs of cataract not be looked for. In acute glaucoma, with general disturbance, it must be admitted that a mistaken diagnosis is more natural. The cases themselves are of rare occuiTence, and the period, moreover, during which it might be possible to adopt a satisfactory line of treatment is much shorter. The pain in the eye and the accompanying blindness, though caused by the same excessive ten- sion which gives rise to gastric pain and vomiting, is generally dis- regarded even by the patient himself. He is more inconvenienced by the general disturbance, and his medical attendant treats him for the acute gastric symptoms, and overlooks their cause. Such a mistake is not likely to occur twice to the same practitioner, yet it is one which in my experience is not infrequent. For this reason it should be remembered that violent gastric attacks may be set up in this way, and that if there be pain in one eye, preceding or acconq)aiiying such attacks, the tension of the eye should be felt and the eye examined. The tension in the case of an acute glaucoma, giving rise to symptoms of this degree of severity, will be found to be greatly increased. It is easy to SECONDARY GLAUCOMA. 375 satisfy one'.s-self that the eye is " stony " hard. An inspection of the eye shows it to be congested, with the cornea steamy and the pupil dilated. The diagnosis is most difficult in the case of the sim})le form of the disease, and here sometimes the difficulty is very great. In all cases the foi'm of excavation of the papilla, the presence of arterial pulsation, more or less irregularity of the pupil, fulness of the episcleral veins, anaesthesia of the cornea, and the condi- tion of the colour and light senses, are the points to which atten tion must be given, or which must be looked for. It must be remembered that an evident increase of tension may be absent at the time of examination. It is -with some forms of atrophy of the optic nerve that one is apt to confound glaucoma simplex ; and, further, there is often great difficulty, where the glaucoma exists along with myopia from choroidal disease, in satisfying one's-self as to its presence. When the data afforded by the objective appearances are not sufficient to justify a diagnosis, and when no very characteristic restriction of the field of vision exists, great help may be obtained by an examination into the state of the field of vision by Bjerrum's method, which in my experience is by far the most delicate subjective test. The light sense should also be tested. In cases of pure atrophy, i.e., such in which the nerve elements of the retina are primarily involved in the process which gives rise to the amblyopia, it is found that while very little more amblyopia is caused by reducing the illumination, and the minimum perceptible amount of light is not markedly less than normal, a very distinct defect exists in the ability to distinguish between different intensities of illumination. On the other hand, the choroido-retinal affections exhibit exactly the opposite conditions with respect to these two elements of the light sense, namely, more or less marked night blindness, with relatively good power of distinguishing between different intensities of illumination. In glaucoma the defects in the light sense occupy an intermediate position, though considerable differences exist in this respect. Secondary glaucoma. — ^luch the same set of symi)toms, and occurring mth different degrees of severity, are to be found in eyes which are the site of other affections, either infiammatory or traumatic. There is then said to be secondary glaucoma, as the glaucomatous symptoms have not originated of themselves, but have followed upon some change which of itself is recog- nised as pathological. When the condition of secondary glau- coma is set up, the risk which the eye runs is the same as when 376 GLAUCOMA. the disease is primary. In many cases the cause of the circul- atory disturbance is apparent, of a more or less distinctly mechanical nature, and, as it were, less intimately associated with the symptoms to which it gives rise. Often the cause can be removed. Thus glaucoma, along with iritis or traumatic cataract, can generally be arrested by operation. This is not generally the case, however, when the cause is a dislocated lens, or a dense leucoma adherens, leading to staphyloma. One form of secondary glaucoma desei'ves special attention, namely, what is called Juemorrhagic glaucoma. In this disease glaucomatous symptoms of varying intensity supervene, generally after the lapse of some weeks, upon an attack of ajx»plexy of the retina. The pain is usually very great in such cases, and the condition may occur in one or both eyes, though fortunately more frequently in one alone. There is often a history of sudden blindness coming on before the attack of the glaucoma. The iris may present the appearance of ha^morrhagic infiltration, or there may be blood in the anterior chamber. The chamber itself is never shallowed in the manner so characteristic of primary glaucoma. The individuals in whom htemorrhagic glaucoma occurs are almost always advanced in life, and the subjects of atheromatous degeneration of vessels. They not infrecpiently die of cerebral apoplexy. A pretty distinct group of cases, complicated by increased intra-ocular tension and other symptoms of a glaucomatous state, ai'e those in which for some cause or other there is an abnormal degree of exudation passing from the iris or ciliary processes, as in serous irido-cyclitis. Other forms of iritis may become com- plicated by secondary glaucoma probably from another cause, namely, an interference with the escape of the aqueous from the posterior into the anterior chamber, which results from the existence of total posterior syuechit^j ; and when secondary glau- coma, owing to this condition, is present, one sees a more or less marked bulging forward of the iris. Traumatic cataract, whether produced accidentally or by operation, is not infrequently followed by increased tension. Two conditions appear to give rise to this, namely, the swelling of the lens substance within its capsule^ and the filling of the anterior chamber with the broken-up portions of the lens. The latter is more likely to cause this complication the greater the mass of lens matter occupying the anterior chamber, and the older the individual in whom the trauma has occurred. Dislocation of the lens is another cause of secondary glaucoma. Intra-ociilar tumours almost invariably, Avhen they have attained SECONDARY GLAUCOMA. 377 any size, give rise to glaucomatous symptoms, wliich are some- times so severe as to render the diagnosis of the primary disease very difficult, owing to the haziness of the dioptric media. Whilst primary glaucoma is almost exclusively a disease occurring late in life, secondary glaucoma is met with at all ages, although undoubtedly more is required to set it up in young eyes than in old. The vision, too, does not appear to be so rapidly or permanently interfered with by the increased tension in young eyes. Two important forms of complicated glaucoma occur — (1) Cataract with glaucoma ; (2) high myopia with glaucoma. Both conditions are fortunately rare. Sometimes one meets with glaucoma after extraction, i.e., in an aphakic eye. Glaucoma may also come on after needling for after-cataract. It is then due to cyclitis. Glaucoma in a highly myopic eye is, properly speaking, secondary, inasmuch as the choroidal changes which lead to the elongation of the globe probably intei'fere at the same time with the circulation in that membrane, and lead to a glaucomatous complication. From a clinical point of view, it is better to look upon the form as a complicated glaucoma. The tension is rarely very high, though above normal ; the field of vision becomes restricted in a manner more or less characteristic of glaucoma, and the papilla is excavated. It is the excavation of the papilla, as well as sometimes the unusual amount of pain complained of, which should lead one to suspect this complica- tion. The excavation is never so deep as in other forms of glaucoma, but it is unmistakable whenever it is seen to reach out to the margin of the papilla. In these cases there is always a very marked and often excessive degree of choroidal atrophy surrounding the papilla. Prognosis. — The prognosis in glaucoma, in whatever form the disease may present itself, is always bad whenever the glaucoma has begun to produce an impairment of vision. The i)remoni- tory stage may exist for a long time, and may even never lead to confirmed glaucoma. It is rare, if indeed it ever happens, that the disease becomes spontaneously arrested ; so that, for practical purposes, we must consider that glaucoma, left to take its own course, invariably leads sooner or later to total destruction of vision. When an operation is performed, the prognosis may ha said to depend on the stage of the disease at which it is undertaken, on the nature of the operation, on the manner in which the operation has been performed, and the way in Avhich healing 378 GLAUCOMA. has taken place. Not a little depends, too, on the form of disease treated, and the presence or absence of complications. The treatment of glaucoma should differ according to the •stage of the disease. Where only occasional i^remonitory symp- toms are present, and vision is therefore good during the inter- vals, there may be a reluctance on the part of the i)atient to undergo an operation. The local application of a miotic may then l)e adopted. A half per cent, solution of nitrate of i)ilo- car}iine dropped into the conjunctival sac speedily cuts short these attacks. At the same time attention should be directed to the general health, and, if the heart's action be weak, iron and digitalis prescribed. A properly performed iridectomy at this stage, not only checks the premonitory attacks, but almost certainly prevents the progress of the disease altogetlier. There should, therefore, be no hesitation in proposing an iridectomy even at the early stage, and all the more urgently if the symp- toms frequently make their appearance, as it is impossible to say how much damage may be done, and done irretrievably, as soon as the disease becomes confirmed. Unquestionably, however, as soon as the glaucoma has begun to interfere permanently with the function of the eye an iridec- tomy should be performed. Iridectomy is the only cure for glaucoma, and is the more likely to be successful the more the iris tissue has retained its normal character. When atrophic changes have begun, much depends upon their extent whether removal of a jjortion of iris will be sufficient or not to permanently arrest the glaucoma. In all cases the iris should be cut as peripherally as possible, but should not be detached from its ciliary attachment. Great care should be taken to prevent any portion of the iris becoming entangled in the wound. This encleisis of the iris is very apt to interfere with the effect of the operation, as the iris is not only dragged upon, but prevents the firm close healing of the external wound which should be aimed at. The first effect of an iridectomy for glaucoma is generally to reduce the tension of the eye. Where it does not do so, the prognosis is mostly, though by no means always, unfavourable. The reduction of the tension very soon relieves the pain which may have existed. In acute cases, where the cornea has been very hazy, the ra})id disappearance of the oedema, to which the haziness is due, admits of considerable impi-ovement of vision, though this may be marred by blood effused from the cut surface of the iris. Bleeding from the iris is not uncommon, and may take place at the time of the operation, or several days afterwards. IRIDECTOMY AS CURE FOR GLAUCOMA. 379 In acute cases there may be added to the improvement of vision, due to the clearing of the cornea, a further improvement, which results fi"om the circulation in the uveal tract assuming a more normal character. Two or three weeks, or even longer, often elapse before the restoration of vision has reached the full amount possible. In subacute and chronic cases the same amount of improvement of vision is not to be expected, and the operation will have served its purpose if the vision existing at the time of its performance is retained. Often, indeed, in the case of simple glaucoma, iridectomy, although arresting the progress of the disease, leads immediately to some deterioration of vision, and this is more especially evident in the peripheral vision, the field of vision being not infrequently found to be narrower after than immediately before operation. It is Avell to remember this, as it sometimes happens that in cases where the nasal portion of the field is restricted to nearly the point of fixation, that point becomes itself included in the blinded area by the slight increase in the restriction following the operation, and the vision thereby rendered all at once very much worse. In more acute cases of glaucoma the previous use of a miotic not only facilitates the performance of the iridectomy, but renders the accidents, which may occur on the sudden reduction of the tension, less liable. It is well, too, in operating for acute glaucoma in one eye, when the other has so far exhibited no signs of the disease, to keep the sound one under the influence of a miotic, as the mental anxiety of having to submit to an operation has not infrequently been observed to induce an attack of glaucoma in the hitherto sound one. In the true ha?morrhagic glaucoma, iridectomy almost cer- tainly leads to further haemorrhage and rapid destruction of vision. In such cases, therefore, the operation is on the whole contra-indicated. In some of the cases of simple glaucoma, in which the tension is not diminished immediately after the operation, rapid loss of sight takes place. To these cases the name of malignant glaucoma has been given. Sometimes the cause of this is a subretinal hiemorrhage. Usually, however, there is a forward displacement of the lens, leading to a blocking of the channels for the escape of liquids at the angle of the anterior chamber. In these cases the proper treatment is to extract the lens. Even when iridectomy fails to arrest the progress of the blindness, it generally protects the eye against the occurrence or recurrence of a congestive attack of glaucoma. Iridectomy is not only capable of reducing tension, but of regulating it to 3S0 GLAUCOMA. a certain extent ; so that when i)erformed for cases of chronic irido-cyclitis, in which diminution of tension has taken phice, it often leads to a more normal tension ; therefore, instead of reducing, it actually incre;ises the hardness of the eye. What- ever be the nature, then, of the curative action of iridectomy in glaucoma, it is certain that it does more than merely reduce tension. In some way or other it also induces a more normal condition of the circulation in the uveal tract. In cases of acute congestive glaucoma, the first thing to be done is to give a subcutaneous injection of morphine. Then, as soon as possible, preparations must be made for the operation of iridectomy. Owing to the great pain which this operation causes in such cases, it should be performed under chloroform. It is otherwise very difficult, even when there is enough assistance at hand, to keep the patient sufficiently quiet. Iridectomy. — The instruments required for iridectomy are — a spring speculum, a ]»air of fixation forceps, a bent triangular lance-shaped knife (often called a keratome. Fig. 157), a pair of iris forceps, or iris hook (Tyrrell's hook), a pair of iris scissors, and a small flexible caoutchouc or tortoise-shell spud. In making the necessary section with the keratome, the operator may either push the point away from him or towards him ; in per- forming an iridectomy upwards, therefore, he will in the first case stand behind the patient's head, and in the second at the side of the patient, and at the same time as nuich in front of him as possible. When there is plenty of room, — that is to say, where there is a good anterior chamber, — either manner of intro- ducing the knife is equally easy. In introducing the knife, however, into a narrow chamber, the second is perhaps the better, as it enables the operator to watch the point much more closely. After the eye has been cocainised, and the con- junctival sac well washed out with the cori'osive sublimate solution, the speculum is introduced, and the surgeon, taking the fixation forceps in the left hand, takes a firm hold of the conjunctiva and subconjunctival tissue close up to the cornea at the opposite end of the diameter in which he intends to make the iridectomy. The knife should then be introduced at the Via. 157. — Kera- tome. IRIDECTOMY. 381 corneo-scleral margin, the point being directed at right angles to the surface in that situation, and pushed forwards until it has just pierced the thickness of the cornea. It is then directed more forwards by depressing the handle, and, with the plane of the blade parallel with the iris, pushed rapidly and without any hesitation on into the anterior chamber. The blade is then slowly withdrawn, with the point tilted slightly more forwards. Tyrrell's hook, or the iris forceps, is then introduced into the anterior chamber. Personally I always use the hook, except in cases where the iris is much tied down by adhesions. The hook should be of platinum, so that it can readily be bent into any shape required. The point should be blunt and perfectly smooth. It is introduced with the hooked end on the flat, passed inwards parallel with the iris, but without touching it, until its end has got beyond the edge of the pupil ; a slight rotation is then given to the instrument, so as to direct its point towards the lens, and it is slowly withdi'awn until it catches well on to the pupillary margin. The iris can then be dragged out of the wound, with the hook kept as flat as is consistent wutli its retaining a good hold of it. It should be slowly dragged out, and without any great traction, and then snipped off with the scissors. With a good assistant it is better for the operator to entrust the scissors to him and maintain fixation himself, with the forceps held in the other hand. Various forms of iris scissors are in use. When the iris forceps is used, it should be introduced closed, until the points lie just over the margin of the pupil, when they are allowed to open, and are at the same time pressed gently down upon the iris. In this way a portion of the iris, including a portion of the pupillary margin, rises in between the two limbs of the forceps, which are then firmly closed and slowdy with- drawn, until a good snip can be got with the scissors outside the wound, which leaves a piece of detached iris in the forceps. A stream of sublimate lotion may now be poured upon the wound. The eye is then closed and gentle friction made over the lid ; in this way any part of the iris caught in the wound is as a rule liberated ; but if the iris should not have returned to its jjlace, it may be gently dragged away, by passing the caoutchouc spud into the angles of the wound and on to the surface of the iris. This must only be done, and with great care, when the first proceeding fails. If there is any bleeding, the upper lip of the wound should be slightly depressed, so as to permit of its escape ; but attempts to remove blood should not be persisted in for any length of time. The bleeding usually comes from the con- junctiva, a portion of which may have been snipped off along 382 GLAUCOMA. with the iris. Care .should therefore be taken, in using the scissors, to see that only iris is inchuletl l)et\veen its ])hules. Witli regard to the performance of iridectomy for glaucoma, the incision made into the anterior chamber should be a \>er[- pheral one, and be made with a thoroughly sharp knife. There is a tendency with some operators to attempt a more peripheral section than can be easily made. They thus render the operation not oidy more difficult, but less likely to check the glau- coma. A sufficiently peripheral section is most efficiently made with the triangular bent keratome, Avhicli should be rapidly introduced and then slowly withdrawn. Occasionally, owing to the eye being deeply sunk, the manipulation of this knife is a matter of difficulty. A Graefe knife may then be used, and the section made by puncture and counterpuncture, cutting after- wards as peripherally as possible from within outwards, and preferably in one sweep — that is, without any sawing motion. It is seldom that this section is as satisfactory as one made with a keratome. Cutting thus from within outwards necessarily, to some extent at least, entails a wounding of the peripheral portions of the iris which lie nearest the corneal wound. It used to be a rule to remove a large portion of iris. In my experience, a coloboma of 4 or 5 mm. diameter is sufficient. Nor is it necessary, as is sometimes advised, to forcibly tear the piece of iris excised from its peri})heral attachment. On the contrary, this may in some cases do harm. Large iridectomies are necessary in cases of closed pupil from iritis. In glaucoma a moderate-sized coloboma and a large and peripheral corneo- scleral section, which should, however, preferably not entail the very apex of the angle of the anterior chamber (though this is usually recommended), and which should be made with a kera- tome, is what should be aimed at. The cases that do best are those in which the section heals quickly, leaving a barely visible scar. The bulging of the cicatrix, or a cystoid character of the union of the lips of the wound, is an indication that the operation has failed to fully relieve the increased tension. And although a cicatrix of this kind may act as a sort of safety-valve for a longer or shorter time, the condition of an eye in which it occurs cannot well be looked upon as quite satisfactory. Some surgeons, however, attach importance to the cystoid scar, and go so far as to look upon it as even desirable. For some time after the performance of iridectomy for glau- coma, it is a good precaution to drop a solution of eserine or l)ilocarpine into the eye two or three times daily. The amount IRIDECTOMY. 383 used may gradually be diminished to one instillation daily, one every second day, and so on, when careful examination of the tension and the visual acuity shows that no recurrence has taken place. An iridectomy which has been properly performed, and which has temporarily checked the disease, seldom fails to etiect a permanent relief. This may, however, happen, and is then due to one of two causes. Either the increased tension returns after some time (it may be with the consolidation of the cicatrix at the corneal margin), or a slow degenerative change in the retina causes blindness. The former seems to be the more common cause, and the question then naturally arises whether any further operation is called for, and if so, what. No doubt, in respect to such cases, there may be some considerable difference of opinion, even amongst those whose practical experience is suthciently extensive to entitle them to hold some view on the matter. It is difficult, perhaps, in such a case not to be influenced by theo- retical views as to the conditions giving rise to increased tension. I have found however, practically, that the treatment most likely to lead to a good result is to reopen the old corneal scar, and at the same time make a fresh wound and remove a further portion of iris. This operation is best done with a Graefe knife, which, being entered at the corneo-scleral margin at some distance from one end of the old scar, is passed out of the chamber at or near the other end of the scar, and the section completed by cutting outwards. A portion of iris continuous with one limb of the existing coloboma is then removed, and thus the coloboma made larger. Von Graefe's plan of making an altogether fresh iridec- tomy directly opposite to the first one is no doubt also effective, but has the disadvantage of causing a greater disfigurement. When the cause of detei'ioration after operation is the second one mentioned, uo further operative interference is called for. The cases in which this result is mostly met with are in my experience those in which the central vision has from the first been relatively more impaired than the peripheral. Probably, indeed, in such cases the increased tension, which in any case has been comparatively slight, is also of subordinate importance in the process which leads to progressive blindness. Iridectomy has so far proved to be the most efficient means of checking glaucoma, whether of the congestive or non-congestive variety. At one time sclerotomy was by many substituted for iridectomy, on the assumption that the beneficial action of the iridectomy depended entirely upon the incision made along the angle of the anterior chamber. There are still some surgeons who 384 GLAUCOMA. apparently adhere to tlie i»ractice of sclerotomy alone, ^fany, liowever, Lave returned to iridectomy, Avliich from jturely iirac- tical consideration.s they have found to give more permanent results. The curative action of iridectomy in glaucoma has never received a satisfactory explanation. While capable of arresting both the acute and chronic forms of glaucoma, it is generally supposed to be more effectual in the former. This may, however, possibly depend upon its being performed, as a rule, in an earlier stage relatively, where the symptoms are acute. The action of iridectomy in glaucoma ai)pears to be intimately connected with, if not entirely dejiendent u})on, the influence which it has in permanently reducing the abnormal degree of intra-ocular tension. It does this, proliably, in three different ways, which may or may not mutually supplement each other. In the first place, the disturbed balance between transudation and excretion of aqueous, which leads to tension, may be given time for readjust- ment, by the escape of the liquid through the wound before healing takes place ; and subsequently the normal main channel for excretion, at the angle of the anterior chamber, may suffice. Or, again, the absorption which takes place normally by the vessels of the iris — the circulation in which is materially altered by the excision of a portion of that membrane— may be in- creased, and thus more efficiently supplement the excretion by the main channel. Lastly, and least satisfactorily, the "safety valve " of a cystoid cicatrix may amount to an additional ex- cretory channel. In accordance with this view of the action of the cut iris, it is found that iridectomy is the more efficient the more normal is the structure of the iris at the time of operation. On the other hand, an atrophic condition of the iris weakens the chance of a satisfactory result from iridectomy. The operation is then often followed by the formation of a cystoid scar. CHAPTER XIV. INTRAOCULAR TUMOURS. Sarcoma of the choroid and ciliary body. — Sarcoma of the choroid i.s usually circumscribed, but occasionally occurs as a diffuse iufiltration. It may be either pigmented or not. The pigmented cases are much the more common. Of 259 cases of sarcoma met with by different observers, the records of which have been collected by Fuchs, sixteen, or 6 per cent., occurred in the iris, twenty-two, or 9 percent., in the ciliary body, and 221, or 85 per cent., in the choroid. Of the twenty- two occurring in the ciliary body, twenty were pigmented. Of the choroidal cases, 196 were pigmented and twenty-five un- pigmented. The most common point of origin for sarcomata of the choroid is at or near the posterior pole of the eye, a little to the outer side of the disc. They take their origin from the layer of big vessels. After the tumour has grown to a certain size in the eye, it perforates the coats and extends outside of it. The sclera is most frequently perforated ; sometimes also the cornea and the optic nerve. Perforation through the sclera takes place at the corneo-scleral margin or in the vicinity of the optic nerve, or sometimes at other parts where it is weakened by the passage of vessels through it into the eye. Often, owing to the resist- ance offered by the sclera, the band of connection between the intra- and extra-ocular portions of the tumour is very small, but more and more of the sclera is usually destroyed as the tumour increases in size, which it may do if left alone until it has attained very considerable dimensions — as large as the closed fist, or even larger. Notwithstanding such an increase in size, the bones of the orbit are very rarely involved. The Ijanph glands in the neighbourhood of the eye are never affected in cases of uveal sarcoma. The tendency to metastasis is, however, very great, as it is by the blood that the tumour ele- ments are carried to a distance. The more vascular the tumour, 25 38G IXTRA-OCULAR TUMOURS. tlie tliinnor and larger itn vessels ; and the softer the new tissue, the niDi'e likely is this to hajipen, and therefore the greater is the malignity of the growth. AVhen the sarcoma grows from the ciliary l>ody, it grows forward into the posterior or anterior aqueous chambers, as well as backwards into the vitreous. It may thus become visible, on aim[)le inspection of the eye, before it attains any very great size. A tumour in this situation occasionally sets up severe irido-cyclitis, by which the diagnosis may at first be rendered difficult. Tumours which take their origin farther back detach the retina in front of them. At first the }»ortion detached lies immediately over the tumour, and it is often difficult, from ophthalmoscopic examination alone, to tell whether the detach- ment is simple or produced in this way. The defect of the field of vision is, in the case of tumour, as a rule sharply defined. There may also be relatively better central vision, when the site of the growth is peripheral, than is generally to be found in simple detachment. The tension of the eye is also an im- portant guide to the differential diagnosis. It is most frequently increased in the case of a tumour ; most frequently diminished when the detachment is idio}>athic. After the tumour has existed for some time and increased in size, the whole retina gradually becomes detached, and assumes the funnel or con- volvulus-shaped form which is characteristic of complete detach- ment. Uveal sarcoma occurs about equally frequently in both sexes, and is for the most [>art a disease of advanced life. Only eleven out of 259 cases collected by Fuchs occurred before the age of 10, only twenty-seven before the age of 20. It is very rarely bilateral. The course of the disease is generally divided into four stages — (1) The quiescent or non-irritative stage ; (2) the irritative or inflammatory stage ; (3) the extra-ocular stage ; and (4) the metastatic stage. The average duration of the first st((f/e is from eighteen to twenty-one months, the lower limit being for cases of sarcoma of the ciliary body, the higher for those of the choroid }iroper. Usually at the first examination a brownish or yellowish pro- tuberance is seen, on which, when the retina is not too intrans- parent, an indistinct and irregular network of vessels may be made out lying behind the retinal vessels. Anteriorly situated growths may sometimes be made out very distinctly by oblique illumination, if the pupil be well dilated with atropine. In the second stage the eye is painful, and the tension more or less markedly increased. Often the condition presents much SARCOMA OF THE CHOROID. 387 the ajipearance of congestive glaucoma. From the idiopathic or primary form of that disease, it is recognised mainly by the ab.sence of any periods of remission, -which constantly occur in true glaucoma. When set up by a tumour, the inflammation and increased tension is usually constant. The duration of the second stage is less than of the first — on the average not longer than a year, and often considerably less. The third stage is entered upon by the tumour perforating and growing externally. The growth then becomes very ra]»id as a rule, and ulceration, accompanied 1)y a purulent discharge, takes place on its surface. The }>ain at this stage often con- siderably abates at first, but rea|)[)ears as a rule when proptosis, owing to extension of the tumour to the orbit or lids, becomes marked. As to the /o«>-^/i and final stage, all that can be determined with any certainty is the period at which metastasis, which most commonly occurs in the liver, reveals itself by the appear- ance of sym^jtoms. The tumour growth may of course begin, and in many cases no doubt has begun, long before it gives rise to any symptoms. Diagnosis. — The chief difficulty of diagnosis presenting itself during the first stage is to distinguish a choroidal sarcoma from idiopathic detachment of the retina. Sometimes, in the case of tumours, there is a circumscribed enlargement of the episcleral vessels over the region of the detachment. This is caused by blocking of one or more of the vena? vorticosiB by the growth. The other points to be attended to in the differential diagnosis have already been explained. Detachment of the choroid might be mistaken for sarcoma, but the suddenness of onset and the diminished tension would be significant. In the second stage of sarcoma a confusion with idiopathic congestive glaucoma might be made, although such a mistake ought to be uncommon if proper attention be paid to all the circumstances connected with each case. In glaucoma the vision has usually been good before congestive symptoms have set in ; there have, besides, often been observed the charac- teristic premonitory symptoms. There is, besides, the constant tendency to intermittence in the pain, and in the increased intra- ocular tension, so characteristic of that affection. When the glaucoma is absolute in the one eye, there ai'e often symptoms of the disease ah-eady existing in the other. In the case of sar- coma, on the other hand, the i)atient has usually been conscious of more or less blindness of the eye before it becomes painful. When the congestive symptoms set in, they are constant. A 388 IXTI^A-OCTLAlt TTMOUKS. l)ri^litisli rcHection from the coiniiletely detached retina can often be seen. liotli eyes are hardly ever atiected at the same time. In cases where the choroidal tumour gives rise to irido- cyclitis, the diagnosis may certainly be rendered difficult, and still more so when shrinking of the glolie takes place as the result of this inHammation, as sometimes haiipens. In idiopathic irido- cyclitis the sight has pro])ably been good before the onset of the inflammation, and is only slowly lost as its progi'esses. It often, too, affects both eyes. The shrunken eye resulting from simple irido - choroiditis is usually painful on pressure, but seldom subject to any great sjtontane- ous i>ain, which, on the other hand, characterises that which encloses a tumour. The in'ognosia in uveal sar- coma, if an oi>eration be not undertaken, is as bad as i>os- sible. The disease is probably invariably fatal, and the time the patient has to live from its first ai)pearance is not much more than five years, and often considerably less. Of the cases on which Fuchs founded his statistics, 285 were operated on, and of these thirty-one, or 13 i>er cent., were followed by local recur- rence of the growth. In most Fig. 158.— Case of sarcoma of the choroid, nf thp MSP'* rppurrencp took ^^i"^^'*"? greatly engorged episcleral ot tne cases lecuiience took vessds and tvimom- as seen by oblique place within a year. Statistics ilhimination. show that if recurrence does not take place within four years after removal of the eye, it is not likely ever to make its ai)pearance. The following table, taken from Fuchs' work on sarcoma, shows well the influence which the stage at which the oi^eratiou is performed has on the liability to recurrence : — Stage. I. II. III. Total Cases. . 21 07 . 117 Recurrence. 5 26 Recurrence Percentage. 5 22 FREQUENCY OF METASTASIS. 389 It is evident, therefore, as might well lie supposed, that the Fig. 159. — P^rom a ua-se ot ,>ui(iiiii,i of tln' clioroid in the second stage, showing the shallowing of the anterior cliamber. danger is only really great in the third stage. Metastasis is, however, ever so much more common, and constitutes the real _ source of danger. There are no statistics, so far as I am aware, which give any idea as to the freipiency of metastasis ; but the proportion of cases where the patient has been known to be alive five years after- wards is not very great. My own experience, however, leads me to believe that it is con- siderably greater than used to be generally sup- posed. One curious and important point brought out by Fuchs' statistics is that metastasis ap- pears just as likely to take place if the opera- tion is done in the first pr Fig. 160. — Case of sarcoma of the choroid, showing also complete lumiel-shaped detacli- nieut of the retina. 390 INTRA-OCULAR TUMOURS. as ill the tliird stage. Ia'Iici', on tliu otlicr liaud, fcjiiiid it less likely to occur it' the primary growth were removed in the first stage. The only possiMe treat nient is to remove the eye. This should lie done as soon as the diagnosis is certain. In the later stages, when the orbital tissues are invaded, the whole contents of the orbit nuist also be removed. Metastatic carcinoma of the choroid has been described. It seems always to occur in both eyes, and usually after carcinoma of the mamma. Fk;. 161. — Section ot eye tilleil with a melanotic sarcoma in the tliird stage, after pert'oration has taken place. Glioma of the retina. — In many resi»ects the clinical features of glioma differ from those of sarcoma when met with in the eye. Glioma shows even a more marked tendency to undergo degenerative changes than sarcoma. These may be fatty, calcareous, cheesy, and pigmentary, the first being the most common. As the mass grows, it causes a disajipeai-auce of the vitreous, and often a loss of transparency of the lens, Avhich, along with the iris, is pressed forwards, causing shallowing of the anterior chamber. After existing for some time in the retina alone, the choroid and optic nerve become involved in the tumour growth. The growth at first occupies mainly the medullary portion of the nerve, and only after involving this portion for some time GLIOMA OF THP: RETINA. 391 spreads to its sheath. This causes in ' many cases an immense tliickening of the nerve, and it is for the most part in this way that extension first takes phice to the brain. It is, as a rule, the extension to the brain that causes the death of the patient. Metastasis does occur ; but far from being an invariable occur- rence, as in sarcoma of the uveal tract, it is comparatively rare. Metastatic glioma has been mostly found in the liver, but has also been met with in the bones, ovaries, kidneys, and lungs. Instead, then, of four stages which can be distinguished in the clinical history of sarcoma, only three characterise glioma — (1) The c[uiescent or non-irritative stage; (2) the irritative or glaucomatous stage ; and (3) the stage of extra-ocular growth. Blindness is a very early symptom of the Jirst staije. It is only comparatively rarely, however, that this symptom directs attention to the disease, as such a large proportion of cases occur in infants, who do not complain until they begin to sutler })ain. Often before this the parents observe a peculiar whitish i-etlection from the eye. This appearance and the accompanying dilatation of the pupil lead to the detection of the disease, often long after its first onset. Owing greatly to the yielding of the sclera, glaucomatous symptoms, or those of the second stage, are delayed until a time when the tumour is much larger than a sarcoma, when it passes from the quiescent to the irritative stage. Children are there- fore often first brought to the surgeon when there is already a good deal of increase in the size of the globe, and, what is worse, when the nerve has to a great extent been involved in the tumour growth. The third stcu/e, or the extra-ocular growth, is ushered in by the perforation usually of the cornea — sometimes, though much more rarely, of the sclera. As soon as the tumour becomes extra-ocular, it grows with great rapidity, involving the tissues of the orbit, of the temporal fossa, of the cheek, and even of surrounding tissues. The lymph glands in the neighbourhood are sometimes affected, but more frequently not. There can l)e little doubt that when metastasis does take place, it is brought about by absorption of particles of the tumour into the blood, and not by transmission through the lymph channels. Occasionally it happens, just as with sarcoma, that an irido- cyclitis is set up, and this may lead to shrinking of the eye. Whether or not shrinking takes place, the supervention of an inflammatory attack of this nature introduces a difficulty in the diaf/nosis. That form of purulent choroiditis which is met with along 392 INTKA-OCULAR TUMOURS. with cerebro-spinal meningitis is the disease most likely to be confounded with glioma. The difterential diagnosis will depend ]>aitly on the history, and partly on the local ap[)earances. In the case of choroiditis there will usually be a distinct history of an illness — fever, drowsiness, and other more or less marked cerebral symiitoms preceding the inHamniation in the eye ; and when the patient is old enough to oljservc, the l)lindness will be said to have come on after the intlamniatiou, aiad not to have existed before it. The whitish reflex from the fundus very closely resembles that caused by glioma, especially if the lens has lost a good deal of its transparency. When it is possible Fig. 162. — Section tlirougli eye and tliiougli the middle of a large glioma of the retina wliicli has begun to invade the optic nerve. to make a closer examination of it, the colour is found to be more of a faint straw, and not the [»inkish-white or pure white characteristic of glioma. There is, besides, not the marked and irregular convex surface of the mass, or the api)earance of retinal and other vessels on its surface, which is met Avitli in glioma. The tension is almost always diminished, and there are also evident signs of inflammation — synechi;^, uveal pigment on the lens cap- sule, etc. An important point to observe, too, is the condition of the periphery of the iris. When thei'e are purulent deposits in the vitreous, the contraction whicli takes place in them leads usually to retraction of the i)erii)heral i»ortion of the iris, and deepening of the anterior chamber in this position. In glioma the tension GLIOMA OF THE RETINA. 393 is rarely low, and may be distinctly increased even before glauco- matous symptoms become evident. The shallowing of the anterior chamber takes place throughout, and is due to the pushing for- wards of both lens and iris. Glioma is less frequent than sarcoma. It is much most common in infants, l)ut has been met with up to the age of 12. The children affected are otherwise healthy. So are their parents, as a rule ; Fig. 16.3.— Section through eye and through there does not apJJCar to large glioma of the retina which entirely ,,g heredity. There is, tilled the vitreous chamber and hail under- -^ ■' ' gone extensive degenerative changes. however, a very marked tendency to several mem- bers of the same family becoming affected with the disease, thou.gli it is rare that this predisposition extends to all the members of a family. Occasionally both eyes are affected, and gener- ally then both at the same time, or one shortly after the other. On this account alone it is evident that the disease in the second eye is indejjendent of the first, and does not spring from a continuity of the growth along the chiasma. But there is absolute pi'oof of this in- dependence in the fact that complete recovery may take place after re- moval of both eyes for glioma. The prognosis in glioma is always bad, and altogether hopeless if the disease is left to its own course. Although the disease is extremely malignant, Fi(i. 164. — Glioma of the retina, complicated with "paeudo-glioma." — From a preparation ])y Dr. Hill Griffitli. 394 INTRA-OCULAR TUMOURS. it is mainly so on account of the great .tendency to extension to the brain. If an opi)ortunity occurs of operating at an early stage, there is a fair chance of eradicating it. It is always advisal)le to remove as long a ])ortion of the ojitic nerve as jiossible when there is much thickening of it. If the opera- tion is done during the glaucomatous or later stage, the whole contents of the orbit should Ijc removed. Even with this l)recaution the chance of I'ecurrence is very great — quite as great as in the case of sarcoma, if not more so. The prognosis is therefore consideral>ly more favourable than in sarcoma if the operation is performed early, while it is, if anything, worse in the third stage. CHAPTER XV. DISEASES OF THE ORBIT. Inflammation of the Orbit. Although it is not always ^lossible to make the ditferential diagnosis, it is important to make a clinical distinction between orbital j^eriostitis and orbital cellulitis. While the former sooner or later extends to the cellular tissue, an original cellulitis does not lead to intlammation of the periosteum or bone. Cellulitis is the more common aftection, being set u}i, as a rule, l)y some trauma, or by the extension of a panophthalmitis, originating often in some severe corneal intlammation. Of purely idiopathic inflammations, however, it should be remem- bered that periostitis is much more frequent than cellulitis. The jjeriostitis may be an extension from some other part, or it may originate in the orbit. It may be merely hyperplastic, or it may be gummatous, and lead to the destruction of the tissue involved. The surrounding cellular tissue and fat frequently particiiiate in the inflammation which has originated in the periosteum, and a more or less localised abscess results, which gives rise to proptosis and great pain. When the case is originally one of periostitis, and the protrusion of the eyeball great, then it may be looked upon as certain that it has proceeded to suppuration. Sometimes fluctuation can be felt ia the orbit, but this is not always the case. The pain is very great, and subject to ex- tremely acute exacerbations, which are apt to come on at night. In many cases pressure over some part of the bone surrounding the orbit gives rise to pain, especially if the pressure is made with the finger passed as far to the inner surface of the orbital margin as possible and directed away from the eye. In this way a periostitis may often lie distinguished from a cellulitis. If, however, the site of the intiammatiou is very far back, there may be little or no pain on pressure over the bone. 396 DISEASES (,)F THE OllHIT. In both periostitis and cellulitis there is more or less cheniosis, as well as swelling and redness of the lid. In cases of idiopathic cellulitis, in which alone, as a rule, there can be a doubt as to the diagnosis, tlie vision is more frequently seriously aft'ected or altogether destroyed than in periostitis. When an abscess does form, it should be opened asei)tically. In the deeper-seated al)scesses, too, it is important not to delay too long in making a free o[)eiung for the escape of tlie pus and for subsequent free drainage. Besides, by direct transmission through the diseased bone forming part of the orl)ital wall, cases Fig. 165. — From a uase of syphilitic gninnia at the ujipur aiiigmented, but melanotic sarcoma has been met wdth originally growing from the orbital fat. It is most frequently, however, an extension from an iutra-ocular tumour. Various forms of sarcoma occur in the orbit, much MALIGNANT TUMOURS. 401 the most frequent Ijeiiig the round and spindle-8hai)ed varieties. The rapidity of their growth depends partly upon the tumour itself, and partly on the age of the patient. Hound-celled sar- comata, as elsewhere, are the most malignant, while the younger the patient the greater is the tendency to rapid growth. The tumour may extend to the brain, and also to the antrum, tem- poral fossa, etc. Sarcoma of the orbit is usually painful — more so, at all events, than most simple orbital tumours. It is usually fatal, although sometimes early removal may altogether eradicate the disease. Occasionally the growth stojts spontaneously, and the tumour undergoes various deijenerative changes. This is. Fig. 166. — from a case of .sarcoma of the orbit causing considerable proptosis. however, an occurrence of such rarity that it can hardly be re- garded as of any practical importance. The treatment consists in removing the contents of the oi-l)it as thoroughly as possiljle. Healing after evisceration of the orbit may be materially hastened by covering the granulating surface after some time with a Thiersch's graft. Tumours of the optic nerve are of rather rare occurrence. As the muscles are not involved in the tumour, the movements of the eye are generally relatively good, even when the proptosis is considerable. The eye, though as a rule soon rendered sightle.ss, remains intact until the protrusion is so great that it cannot be 26 402 DISEASES OF TFTE ORBIT. covered with tlie liils. Until the cornea becomes affected from exjiosure, there is complete absence of pain. A very consideral>le degree of anteroposterior flattening of the eye may take jtlace as the tumour increases in size. The eye, when enucleated, may thus have an appearance which is different in this resjject from that caused by other orbital tumours. A suspicion that a tumour in the orbit was of this nature should be raised by the movements of the eye being good, by the early, though not aljsolutely sudden, loss of vision, and by the comparative absence of ]iain ; but the diatjnosis cannot always l)e made with any certainty. In some cases of sarcoma of the orbit sudden l)lindness may come on, jirobably owing to compression from hiemorrhage. The progress of these cases of optic nerve tumour is very slow, generally lasting for many years. Most have been myxo- mata, or combinations of other forms of tumour with mucoid tissue. The tumours do not involve the outer sheath of the nerve. The result of operation has not generally been satis- factory. In one of the cases on which I operated, no recurrence took place. In another, in which I removed the tumour by Krtenlein's method, leaving the eye, there was no recurrence after three years. The tumours are always found to be encapsuled ; but, unless removed at a comparatively early stage, may have spread too far backwards along the nerve to admit of complete removal. Tumours which extend to the Orbit from ADJACENT Parts. Encephalocele. — This is a very rare occurrence in the orbit, although the possibility of its existence should be borne in mind. The diagnosis could hardly be a matter of difficulty, when, as has mostly been the case, the ap})earance i^resented is that of a fluctuating, somewhat transi)arent, and more or less distinctly pulsating tumour at the inner angle of the orbit, pressure on which causes its disappearance, and at the same time gives rise to sym})toms of cerebral irritation. The history, too, of its being congenital is of diagnostic importance. In some cases, howevei-, there have been complications which have rendered the diagnosis difficult; thus the encephalocele has been completely shut off from the cranial cavity so as to form a true cyst, or the skin covering it has been abnormally supi)lied with blood vessels, giving rise to the appearance of a ntevus. In such cases the ANEURYSM OF THE ORBIT. 403 appearance of hydrocei)lialu.s, as Berlin .suggests, would weigh in favour of the growth being an encephalocele, and further evi- dence would be atibrded by the condition being bilateral, or by the presence of an undoubted encephalocele in some other situa- tion. The large and rapidly-growing tumours of this nature soon prove fatal, generally in the first few weeks, so that it is only in the case of the smaller ones, where it becomes possible for the i)atient to attain to full growth, that there is likely to be any doubt as to its nature. In any case it is probably safest to avoid intei-ference. Nasal polypi sometimes extend into the orbit and cause dis- placement of the eye. More or less complete blindness is thus jjroduced by jjressure. 2'umours of the efhtnoid, sjihenoid, and antrum may spread to the orbit. Primary sphenoidal tumours appear to be very rare. Tumours of the lids and skin of the face — epithelioma principally — may spread eventually into the orbit and cause exophthalmos. Aneurysm of the Orbit. Aneurysm of the orbit is not an extremely rare affection. Sattler collected records of 106 cases from the literature of rather more than seventy years. Apart from the fact that many cases remain unpublished, in this country at all events, — and of such I have myself seen eight, and heard of several more, — the atten- tion which has recently been drawn to the subject has led to the publication of a number of cases. The aneurysmal protrusion of the eye is usually on the one side alone, but may be bilateral. The bilateral cases form, prob- ably, about 7 per cent, of all cases. The symptoms of aneurysm of the orbit are — exophthalmos with pulsation to be felt over the eye, and a more or less con- tinuous murmur, which can Ije heard over the forehead and eye. On pressure over the protruded eye it can to a great extent be replaced, and on relief of the pressure it immediately returns to its former jjosition. The vessels of the lids are greatly distended, and the lids themselves red. The retinal veins are found on ophthalmoscopic examination to be very greatly dilated, often exhibiting a marked pulsation, while at the same time the arteries are usually diminished in calibre. There may sometimes, too, be found an a})pearance exactly like neuritis. The subjective symptoms complained of are pain and noises in the head and ears. The pain may be excessive, and is gener- 404 DISEASES OF THE ORBIT. ally most distressing at an early stage of the atfectioii. The noises appear to ])e much more troulilesome in some cases than in others ; they sometimes greatly interfere with sleep. They cease, or are much diminished in intensity, Ijy compression of the common carotid artery, which at the same time causes the murmur anil pulsation over the tumour to disai)pear. When the aneurysm, as is usually the case, is suddenly formed, the patient is conscious of a great noise, which is sometimes ilescribed as like the report of a pistol or the crack of a whip, in the head. Fig. 167. — Aneurysm ol' the orbit. — From a case ol ]Jr. Argyll Robertsou's. Aneurysm of the orbit may 1)6 either idiopathic or traumatic. The latter is caused mainly by severe injuries to the head, which have generally at the same time pi'oduced fracture at the base of the skull. A few cases have been the result of penetrating wounds in the orbit. Traumatic orbital aneurysm is more common in men, who are more exi)osed to accidents, than in women. Idio- pathic orbital aneurysm, on the other hand, has been met with more- often in women than in men. Sattler's statistics give over 70 per cent, in women, and from 30 to 50 as the most connuon age for its occurrence. All the cases I have seen have been in women. ANEURYSM OF THE ORBIT. 405 There are a good many different possible causes of aneurysmal })roptosis, and no doubt most of these have actually happened. The following have been demonstrated on post-mortem examina- tion : — Spontaneous as well as traumatic rupture of the internal carotid artery in the cavernous sinus, aneurysm of the o^jhthalmic artery in the orbit, and of the same artery in the cranium. The first is undoubtedly by far the most frequent cause. The effect of the giving way of the arterial wall in this position is to cause an increased pressure within the sinus, and a consequent retarda- tion of the current in the orbital veins, and therefore mainly in the ophthalmic vein. Pulsation, however, probaljly only begins when, after dilatation of the veins, the blood current is reversed in them, so that arterial blood courses through the dilated o^th- thalmic vein. On this account it is generally found that some considerable time elapses between the occurrence of the lesion which has caused the rupture, and the establishment of a pulsat- ing tumour in the orliit, with exoi)hthalmos. The p'''f)gnosis of orbital aneurysm is bad as far as the vision goes when the case is left to itself, but the condition seems rarely to cause death. A few cases have undergone a spontaneous cure, probably from thrombosis which has spread to the sinus, and has eventually even led to a closure of the aperture in the arterial walls. The treatment of orbital aneurysm may be divided into medical and surgical treatment. The fact that several spon- taneous cures have taken 2)lace might well encourage a trial of such measures as are likely to diminish the blood pressure and favour coagulation, befoi-e resorting to any more radical inter- ference with the circulation of the parts affected ; and indeed by I'est, low diet, local or general blood-letting, the api)lication of ice compresses over the orbit, and the intei-nal administration of tincture of veratria, iodide of potassium, etc., good results appear actually to have been obtained. Various surgical methods calculated to lead to coagulation in the vessels of the orbit have been from time to time tried. Of these, the safest is undoubtedly electrolysis. This treatment is not likely, as a I'ule, to lead to sufficient coagulation in the case of the common cause of aneurysm of the orbit, namely, rupture of the carotid in the cavernous sinus, to effect a firm closure of the breach in tlie arterial wall against an undiminished blood pressure. A larger range of usefulness might be expected by combining electrolysis with digital compression of the common carotid on the affected side. Compression alone, though it has led to a few cures, has, on the whole, been unsuccessful ; still it should 40G DISEASES OF THE OKHIT. always be given a trial before resorting to ligature, and especi- ally would it be atlvisable to make the trial in conjunction with electrolysis. Ligature of the common carotid has proved success- ful in rather over GO j)er cent, of the recorded cases in which it has been tried. The cure has usually l)een effected within six 'weeks after the oi)eration, though in some instances it has been delayed for a good many months. When it fails, the treat- incnt should consist first in digital comjircssion, and afterwards ligature of the other carotid, which has in two cases at least l)een successful. In cases in which recurrence takes place after ligature of the carotid, it has usually done so very shortly after the operation ; and indeed, as a rule, it is not many hours after the stoppage of this channel that the i)ulsation and nuirmur over the tumour make their ap[)earancc, even in the cases which are eventually cured by the ligature. Some cases have, however, only recurred after an interval of several months. Injuries to the Orbit. Bleeding into Tenon's capsule. — A disagreeable and some- what alarming contretemps occurs occasionally during the per- formance of tenotomy of the recti muscles for strabismus. All at once the eye is found to begin to jirotrude, and in a few seconds becomes rigidly fixed, so that if the o[)eration is not completed, it then becomes im})ossil)le to complete it, and indeed the lids can hardly be separated. This is due to bleeding into Tenon's capsule. I have observed it altogether about a dozen times, both in my own practice and that of others. Generally, it is owing to the opening made in the cajisule being too small for the escape of blood, which, when an unusually free bleeding occurs, may take }»lace into the capsule, from which it cannot be dislodged even if the o{)ening be at once made, as it rapidly passes all round the eye and coagulates. No harm seems ever to result from this accident beyond a very black eye. When it occurs, the patient should be kei»t in l)ed for the day, and ice compresses'applied over the eye for some liours, until the swelling becomes less tense. Other cases of effusion of Ijlood inside the orbit are caused by ^perforating wounds or injuries to the head, which have usually at the same time led to fracture of some of the bones of the orbit. Protrusion of the eye from lijemorrhage into the tissues behind it is a condition which may generally be inferred to be [)resent when the proptosis has taken place suddeidy after a severe blow on the head. It is a sympttnu of great gravity, as FOREIGN BODIES IN THE ORBIT. 407 even the few cases which have been recorded, where there has been no fracture of the orbit, have ended fatally, while it is almost a certain indication of such a fracture. Sometimes, indeed, there can be no doubt of this, as the blood escapes by the nose or mouth. That which is caused by a perforating wound is not so serious, and generally, if it has not caused an aneurysm, becomes absorbed in a few weeks. Besides the exophthalmos caused by the hajmorrhage, there is more or less ecchymosis produced after some time in the conjunctiva and lids, which renders the diagnosis of the cau.se of the protru- sion easy. Where there is a fracture of the orbit, it not infrequently happens that the line of fracture passes through the optic foramen, and thus, by laceration of the nerve or haemorrhage into its sheath, gives rise to sudden blindness. Foreign Bodies in the Orbit. Foreign bodies of ditferent sizes may become lodged in the orbit. Often this accident happens without the patient being Fig. 168. — Piece of clay pipe stein removed from the orbit (natural size). aware that anything has entered the orbit. For instance, it may result from a fall on some sharp piece of wood or branch of a tree, which has broken off and remained embedded in the orbit, but not observed owing to the patient being at the same time stunned. At other times it is caused by the breaking off of a knife or some other weapon with which the patient has been accidentally or intentionally wounded in this situation. Several foreign bodies even may be lodged in the orbit as the result of some explosion. Fig. 168 i.s a drawing of a piece of a clay pipe stem which I removed from the orbit of a young man. It was deeply embedded, and remained there for ten days, without causing an abscess or in any way damaging the eye. I have seen two other cases of the same accident. The possibility of a foreign body being present .should always be borne in mind in connection with the treatment of cases of penetrating wounds of the orbit. An accident of this nature is not so very uncommon, and most frequently the foreign body is 408 DISEASES OF THE OTIP.TT. situated to the inner side of the orbit. It causes exoi>hthahnos, the eye at the same time being disjikiced in accordance with the lK)sition occupied by the foreign liody. The dia(/nosis may be difficult, l)Ut can generally be made by careful probing. The treatment then consists in removing the obstacle, which usually, unless there be others present as well, soon leads to healing. Sometimes the injury causes death. When this is the case, it is generally either owing to the direct wounding of the brain, or to hitmorrhage. Graves' Disease. The main symptoms of this disease are — (1) Rapidity of the heart's action; (2) enlargement of the thyroid; (3) protrusion of the eyes. The association of the two last symptoms have led to the name exojjhtlialmic f/oitre, which is frequently used as synonymous wdth Graves' disease. All these symptoms are not invariably met with in Graves' disease ; thus there may be i)alpitation and goitre alone, or with hardly any appreciable jrt'otrusion of the eye, or the ])alpitation may exist along with ])roptosis alone, the thyroid being not apprecialjly enlarged. The increased rapidity of the heart's action is the most con- stant and essential symptom, so that although exojihthalmos from Graves' disease may exist without any apprecial)le cardiac acceleration, the diagnosis of the true nature of the i)rotrusion of the eyeballs under such circumstances is difficult or altogether uncertain. In most cases the heart beats amount to from 100 to 160 in the minute, but they are sometimes more frequent. The pulsation is felt very distinctly over the carotids, w^hich are most frequently what have been called "hammering carotids." They, as well as other arteries of the head, are dilated. The A'eius in the neck are also dilated, and on auscultation over them a haimic murmur can generally distinctly be heard. The goitre has usually a soft elastic feeling, and communi- cates to the hand either a very distinct pulsation or a thrill which is synchronous with the systole of the heart. The en- largement varies very much in different cases ; it is rarely extreme. Not infrequently the one lobe of the thyroid, and almost invariably the right, is more enlarged than the other. Cases are on record where death has occurred from dyspnoea, caused by the pressure of the enlarged thyroid on the trachea. In other cases, again, it has been found necessary to remove the isthnms to prevent this occurrence. GRAVES' DISEASE. 409 The exophthalmos is almost always bilateral, though not infrequently one eye is protruded more than the other. Occa- sionally it is altogether confined to one side. The protrusion of the eye takes place directly forwards ; and in most cases, and always where the disease has not existed for any great length of time, the eyes may be pressed back into the orbit without much difficulty, but regain their former position on the relief of the pressure. A hajmic murmur may be heard on auscultation over the eye. The degree of protrusion varies very much. In many cases it goes on increasing slowly or rapidly for some time, and then again becomes less ; in others it remains pretty much the same, though subject to slight differences, according to the patient's state of health. It may be so excessive as to render it imi>ossible for the lids to cover the eyes, or even cause the eyes to become dislocated out of the orbit. Such a degree of exoph- thalmos is, however, very exceptional. The exophthalmos of Graves' disease is in most cases accom- panied by a frightened, staring appearance, which is very charac- teristic, and due to the greater than normal retraction of the upper lid. This involuntary widening of the lid apertui-e generally goes by the name of " Stellwag's sign." Stellwag pointed out at the same time, that in cases which exhibit this symptom there is a more or less complete absence of involuntary blinking. This retraction of the upper lid is not met with in other forms of exophthalmos, and is therefore a point of diagnostic importance in the cases where exophthalmos is confined to one side, or not accompanied in a marked degree by the other symptoms characteristic of Graves' disease. It is generally supposed to be due to contraction of the unstriped nniscular fibres of Midler. Ferri has, however, adduced experimental evidence which seems to indicate that shortening of the levator palpebriB superiori, due to the mechanical effect of its vascular engorgement, may be the cause. An a})i)earance very similar to Stellwag's sign is produced by cocaine dropped into the eye. A more important, though less frequent, symptom is that which is called " Graefe's sign." This consists in the loss of association of the movements of the up|ier lid with the eye. Thus, when the eye is directed downwards, the upper lid either does not follow it at all, or more frequently moves along with it for a certain distance and then remains stationary. Graefe's sign is also highly characteristic of Graves' disease, and is not found at all, or only extremely rarely, under other circumstances. It may be seen, like the retraction of the margin of the upi»er lid, before proptosis takes place, or may occasionally first make 410 DISEASES OF THE ORBIT. its aiiitearance later. It may also not be present during the whole course of the disease, Imt (lisajJiiear after having existed for some time. It is absent in some cases in which Stellwag's sign is well marked. Notwithstanding the in-esence of these characteristic symp- toms, there is no defect in the closing of the lids, the voluntary movements of which are retained just as in health, so that it is oidy when the proptosis has 1)ecome very excessive that the eyes cannot l)e properly covered. In such cases, and even it would apjiear in some cases in which the lids can still be made to afford a sutticient covering, a kind of neuro-[»aralytic keratitis takes place, which is extremely likely to cause destruction of the cornea. In this way, Init apparently only in this way, is the sight endangered by the disease ; but such cases are also the ones in which the jjrognosis is serious for the life of the ])atient as well. Besides the main symptoms of Graves' disease which have now been described, there are other more or less constant ones. One, which in women at all events is often most marked, is an excessive degree of nervousness. The patient is easily startled and frightened, and very readily blushes or is .subject to attacks of perspiration. In some of the worst cases rapid emaciation also takes place. More or less anaemia is generally present at the same time, and this may in Avomen be accompanied by menstrual disturbance. Graves' disease is very nuich more fre(jueut in women than in men. More than half of the cases in women occur between the age of puberty and 30, a very few before puberty or after the climacteric period. In men, although cases are also met with in young individuals, the average age for the disease to make its ap})earance is between 30 and 50. It often seems to come on after mental anxiety, worry, or shock. The course of the disease is usually very chronic. It may last for years in much the same condition, or occasionally un- dergo an ini[)rovenient in one or more of its symptoms. After continuing in this way for some time, the .symptoms gradually in great measure subside, though frequently some enlargement of the thyroid, and often a not inconsiderable degree of exoph- thalmos, permanently remain. Again, a number of cases never completely recover. The frequency of the disease in women, and its occurrence mainly during the child-bearing period of life, has led many to V)elieve that Graves' disease is intimately connected with affec- tions of the reproductive organs. The occasional occurrence of GRAVES' DISEASE. 411 the disease in Avomen at other times of life, as well as in men, and the absence frequently of any menstrual disturl)auce, would, on the other hand, point to such a connection not being very intimate. In these cases, too, in which derangements of menstruation are observed, they may well be ascribed to the condition of anaemia, which is so frequently present in this disease. Unmarried women seem to be more subject to the disease than married, and pregnancy is supposed by many to exert a favouralile influence on it. The iKitholo(!y of Graves' disease is still very obscure. Post- mortem examination in cases M'hich have ended fatally has done very little to clear up the difficulty. Some change in the orbital fat — hypertrophy, enlargement of the vessels, etc. — has generally been found. There can be no doubt that both the enlargement of the thyroid and the exophthalmos are originally due to engorgement of vessels, and it is not unlikely, again, that after long continuance of the process some hypertrophy of the tissues may take place. Still, the protrusion of the eye is mainly a vascular one. Treatment. — There is cei'tainly nothing which can be said to approach the nature of a specific remedy for Graves' disease. jSIany things have been tried : iron, iodine, belladonna, veratria, bromide of potassium, and other drugs ; but though all have had their special advocates, their direct beneficial ettects on the disease cannot be regarded as more than doubtful. The most im})ortant indications for treatment are — freedom from excitement and worry, and change of air. If drugs are used at all, iron and bromides are perhaps the best ; iodine, too, may be used as an external application to the goitre. A few cases have been apparently improved by removal of the goitre ; but except where it endangers life by pressure on the trachea, such treatment would not be justifiable. In cases where the protrusion of the eye is excessive, the lids may be kept closed by bringing them together by means of horse-hair sutures. Enophthalmos, or the sinking back of the eyeballs into the orbit, exists as a consequence of the disappearance of the orbital fat in very old peoi^le. It is also met with in some cases where there has been fracture of the bones of the orbit. It has occasionally been observed, too, apparently as a rare vaso- motor affection, but little is known of the pathology of this form. Shrinking of the orbit occurs sometimes when the eyeball has been removed in early childhood. The diminution takes jtlace mainly, if not entirely, by approximation of the roof and floor of the orbit, while the sides retain their normal dimensions. CHAPTER XVI. AMBLYOPIA AND OTHER ANOMALIES OF VISION. There are various alterations of vision Avhicli are not accom- panied by any very definite objective signs. There may be com- plete blindness (amaui'osin), or more or less defective vision \am1)l yopia), which does not arise from any lesion of any part of the eye itself. The diagnosis of the cause of an amblyopia or amaurosis is often difficult enough. A careful study must be made of the subjective symptoms so far as they can be elicited. To some extent, too, one may be guided by the other coexisting conditions. In some cases the colour vision may be defective, in others a particular portion of the field of vision may be lost or be functionally inactive. In others, again, the light sense may be abnormal. Under this category come cases of night blindness, in which vision may be normal in daylight, but defective so soon as the illumination of objects looked at is reduced beyond a certain degree. Congenital amblyopia. — Defective vision, when congenital or originating early in life, often escapes observation until the dithculties experienced at school attract attention. The higher degrees of amblyopia are mostly associated with nystagmus. It is by no means an uncommon thing to find very considerable amblyopia and nystagmus without any marked olyective cause, either in the dioptric or percipient parts of the eye. In such cases there is usually a histoi-y of early severe inflammation of the cornea, followed by dense opacities, which have slowly cleared away, leaving little or no trace ; or of some cerebral afiection, which has interfered, more or less completely, with the visual centres, and which has been followed by only jjartial recovery. Congenital amblyopia, too, unaccompanied by nystagmus, is very frequently met with without there being any objective sign or any history to account for it. Frecpiently the degree of amblyopia where there is some defect is nuich greater than can SIMULATED AMBLYOPIA. 413 be accounted for by the defect alone. When amblyopia i.s present only in one eye, it is still more likely to pass unol)8erved, unless, as is frequently the case, it gives rise to straVjismus, owing to the existence of other causes which predispose to that condition. Often a unilateral congenital amblyopia is only accidentally discovered late in life, when anything, some trifling accident to the eye, it may be, has drawn the individual's atten- tion to it. Simulated amblyopia. — Amblyopia is sometimes sinuilated. In this country it is rare to meet with this, and the decei>tion is not so well carried out as a rule that there is much difhculty in detecting it. In other countries, where there is a compulsory military service, simulated partial or com})lete blindness is very common. There may be a sinuxlation of either bilateral or unilateral defect of sight. The latter is by far the more common, and fortunately, to(j, it is the more easily detected. It is mostly an amblyopia, and not a complete blindness, of the one eye which is feigned. The diagnosis may then not be at all easy. When bilateral amblyopia is simulated, a little ordinary care on the part of the individual is all that is required to make it almost impossible for one to detect it with certainty. Yet it is strange how often some inconsistency between the admitted sharpness of vision found on examination for distance and for near, or in connection with the glasses which are admitted to eftect some improvement in vision, aftbrds a clue to the character of the aml)lyopia. Often one finds, for instance, very considerable improvement of vision by the use of a convex and concave glass, which exactly neutralise each other. It requires, on the other hand, a very great amount of care, and considerable knowledge of the subject, to simulate well uniocular amblyopia. The certainty of the diagnosis depends ^tretty much, too, on the degree of the pretended blindness. A great number of tests have been devised for the detection of this kind of deception, all of which it is pi-obably possible to elude. An easily applied test is that which can be made with Snellen's coloured letters. These are transparent red and green letters of different sizes. The patient is first made to read them out without anything before his eyes. A pair of reversible spectacles, one eye of which is of green glass, and the other of red, is then put rapidly u})on his nose, cai-e being taken that the eyes are all the time kept open. As the green glass entirely excludes all the rays from the red letters, and the red all the rays from the green, some of the letters are visible only to the 414 AArr.LYOPTA AND OTHEFI ANOMALIES OF VISION. one eye, and others only to tlie other. Any mistake made in the reading of the letters is in this way easily detected. The slightest blinking of one eye is sutHcient to show one with which eye eacli particular letter is seen, so that with care it is i»ossible for a clever deceiver to avoid falling into this trap, although the manner in which the individual ])ehaves may be generally sutti- cient to arouse or confirm one's suspicions. Another simple test, in cases where comj)lete or almost com- plete blindness of one eye is sinuilated, consists in holding a prism, with its base directed ujiwards or d(jwnwards, in front of the good eye. If this jtroduces diploi>ia, there is evidently vision in both eyes ; but the object of this test, again, is of course easily defeated by anyone denying that he sees double. An important m(jditication of the test is made by Alfred Graefe. The indi- vidual tested is made to shut the blind eye, and the prism is held in front of the good one, in such a position that some of the rays pass into the ]>upil through the prism and some directly. This causes uniocular diplojiia. The patient, thus thrown off his guard, often admits that he still sees double when the blind eye is uncovered, and the position of the prism altered to the slight extent required to intercept all the rays jjassing into the pupil of the one eye, under which circumstances the diplopia is of course binocular, and its continuance is a proof of vision in the eye said to be blind. A good plan in cases of simulated uniocular amblyopia, and one which at the same time affords some test of the degree of visual acuteness in the eye said to be defective, is to cause the patient to read through a strong convex lens ( + 5'0 or+6"0, if he be enmietropic), and then to slowly withdraw the print beyond the jjoint at which it can be distinctly read through the lens. If under these circumstances the patient still continues to read, he must be doing so with the eye which he asserts to be amblyopic. Von Graefe's test of placing a prism, with its base dii'ected inwards or outwards, in front of the seeing eye, and observing whether a convergence movement is thereby induced, is perhaps the best test for simulated amaui'osis of one eye ; because, where binocular vision exists, such a movement always takes place involuntarily, owing to the unconscious desire for the fusion of the two images. Amblyopia and amaurosis due to changes at the visual centres, etc. — A good number of cases of amblyopia and amaurosis occur more or less suddenly, and unaccompanied, for the time at least, by any ophthalmoscopic changes. In such cases AMBLYOPIA AND AMAUROSIS. 415 the diagnosis has to lie made from a consideration of tlie histi^iy. When the blindness comes on in the course of a severe illness, oi' during the period of convalescence, — for instance, in scarlet fever, puerperal albuminuria, etc., — the cause is more often urt^mic, and the prognosis favourable, more especially if the pupils con- tinue to respond to light. Amblyopia or amaurosis occurring after severe hsemorrhage is very unlikely to be recovered from, and is generally followed some time after by optic atrophy. The prognosis is even worse in cases of unilateral amaurosis after a severe fall on the head. These cases are of pretty fre- (|uent occurrence, and are proliably almost invariably due to laceration of the optic nerve, or htemorrhage into the sheath of the nerve, owing to fracture of the roof of the orbit, the line of which fracture usually passes through the optic foramen. The atrophy to which this lesion gives rise is not visible ophthal- moscopically until after some time. The blindness which one meets with in young children, after severe cerebral symptoms, is unaccompanied by ophthalmoscopic changes, and is due to interference with the functions of the visual centres. It is often partially recovered from, but may be permanent. The rare cases of blindness from lightning have not as yet received a proper explanation. On the whole the prognosis seems favourable. In cases of lead poisoning very considerable blindness is some- times produced. I have seen the blindness so great that there has been doubtful perception of light, and yet recovery take place. Some of the symptoms in these cases, more especially with respect to colour vision, are often very similar to what is met with in hysterical amblyopia. As in that form of amblyopia, too, there seem to be considerable differences in the nature of the visual defect, and also a good deal of inconstancy about the symptoms of any particular case. Amaurosis from lead poison- ing, when unaccompanied by ophthalmoscopic changes, ajtpears most frequently to be transient. It is one of the rarest symptoms of lead poisoning ; and although different explanations have been offered, the true nature of the blindness is unknown. Central toxic amblyopia. — The symptoms of this rather common affection are — gradual failure of sight, to nuich the same extent in both eyes ; absence of any restriction of the field of vision, or indeed of any interference with the functions of the peripheral portions of the retina ; and the existence of an oval scotoma, most marked for colours, extending from the point 416 A^fRLYOPTA A\D OTHER ANOMALIES OF VISION. of tixatiuii, which it involves, to the blind spot. Most of such cases are met with in men after the age of 40. Tliis form of amblyopia is very rare in women, though not (piite so rare as was at one time suiiposed. Those who suffer from it are almost invariably smokers ; and generally they have smoked for many years before becoming affected. It is very doubtful if alcohol has anything to do with it. Certainly those affected not only smoke, but often also drink to excess ; yet the same symptoms are never observed to follow the excessive use of alcohol alone, though they are very frequently met with in smokers who abstain completely from alcohol in any form. As a rule, when the affection liegins, no change has been recently made in the amount smoked. On this account })atients rarely suspect the cause of their amblyopia. Indeed, they not infrequently begin to smoke more after their sight has begun to fail, on account of the worry that this causes. Very often smoking is indulged in on an empty stomach, the first thing in the morning or very late at night, or, in the case of bad sleepers, during the night. It is owing to this circumstance, probably, more than to the difference in the kind of tobacco smoked, that tobacco amblyopia is more common in the working than in the educated classes. ]\Iany men have to rise early and work several hours before partaking of a substantial meal, but nevertheless smoke during this time. The fact of the toxic ettect of the tobacco getting at some particular time the upjier hand, although individuals have smoked as much and often more at other times, and continu- ously for years, points to there being some recent diminution in the power of resistance. What this has been it is not always easy to find out. Sometimes there has been some slight indis- position or dyspepsia, sometimes loss of blood, at other times merely sleeplessness, aiixiety, or trouble. A frequent cause, no doubt, is the undermining of the system produced l)y alcoholism, so that alcohol may thus be indirectly a factor in the etiology. When any such pretlisiiosing cause exists, then smoking at a time when there is no counter stinuilus of the food renders the poisoning action much more likely to take effect. According as such causes, too, are more or less pronounced, and dependent no doubt as well upon the individual tolerance of tobacco, we find in different cases of this form of amblyopia that the patients have been in the habit of smoking very different amounts of tobacco. As a general rule not less than 3 to 4 oz. of strong tobacco are smoked in the weelr, often much more — in ex- ceptional cases less. In W'Omeu a smaller quantity suffices to CENTRAL TOXIC AMBLYOPIA. 417 bring on the symptoms. The same .sjTiiptoms are produced by chewing tobacco. It would be strange indeed if tobacco were the only poison which gave rise to central amblyopia. Cases do occur in which it is doubtful whether tobacco is the cause, as, for instance, when the amount consumed is very small, or where the blind- ness appears to have come on some time after smoking has altogether been given up ; but, with the sole exception of bisul- phide of carbon, which produces much the same symptoms, the evidence in favour of other poisons is as yet very far from conclusive. Some cases of retrobulbar neuritis very closely resemble toxic central amblyopia, more especially when the defect produced by that inflammation is pretty similar in both eyes. Fig. 169. — .Showing, by shaded area, shape and position of scotomata in central toxic amblyopia. The defective area or scotoma is oval in shape, ^Nith its long diameter horizontal, and stretches from the outer side of the blind spot to very slightly to the inner side of the point of fixation. It corresponds to the external projection of that portion of the retina which lies between the ojttic nerve and the outer margin of the macula, a portion which is supplied by a special bundle of optic nerve fibres — the so-called papillo-macular bundle. The form .sense as well as the colour .sense is defective over this area, but the patient is not conscious of a limited defect — that is, it does not appear in the form of an oval dark spot in the field of fixation, or, in other word.s, there exists what is called a negative scotonm. Practically all that is required to diagnose a central scotoma is to cause the patient to fix some object, preferably on a dark background, a foot or two from his faee, and then to hold a 27 418 AMBLYOPIA AND OTHER ANOMALIES OF VISION. small piece of coloured paper, first 2 or 3 in. to the outer side, and then a similar distance to the inner side of the point of fixation, when it will be found, if the scotoma is marked, that the colour is not recognised in the first situation, but is immediately recognised in the latter. As the defect is most marked for red and green, only these colours need to be used, unless there shoixld happen to be at the same time con- genital i-ed-green confusion, when blue and yellow must be used instead. The limits of the scotoma can be mapped out with the colours, but for this purpose smaller squares should be used, and the shade not taken too bright. By using very small white objects at a greater distance, the corresponding form-sense defect in the scotomatous area may usually readily be detected ; that is to say, an absolute scotoma for white is also to be found. When the scotoma is not very pronounced, and the visual acuity consequently not greatly reduced, there is more difliculty in demonstrating its existence ; it will then be found that although the ordinary colour of the test square is recognised to the outer side of the point of fixation, it appears more vivid and distinct when removed to the inner side. By using light shades of red and green in such cases, or simply by testing at a greater distance, the defective colour sense can be demonstrated Avith certainty. As it is only over a particular area that the colour sense is impaired, the patients are often not aware of the colour defect they have acquired : a large surface of red or green appears to them quite as distinct as formerly. Individuals with tobacco amblyopia often complain of seeing worse in a strong light. This is owing, apparently, to some co-existing hyperassthesia of the retina, which causes any glare to be uncomfortable. They see white letters on a black background better than the ordinary black letters on a white ground. The 2^'>'0[/nosis in tobacco amblyopia is on the whole very good. A large proportion of cases completely regain vision if the tobacco is stopped. Improvement, though less rapid, generally takes place when the amount consumed is reduced, or when the quality of the tobacco used is milder, or if cigars be substituted for pipe smoking, Avhich is very much more injurious in this respect. It is also more likely to take place if smoking be indulged in only after meals. Sometimes, though very rarely, recovery may take place without any change of habit. When this happens, it is probably to be explained on the assumption that some condition of the system, which has permitted the CENTRAL TOXIC AMBLYOPIA. 419 tobacco to get the upper hand and produce its poisonous effects, has been so far recovered from as to enable the individual to throw off the poison, notwithstanding the cumulative action which has taken place. It is not probable that the symptoms have been due to anything else. A very varying time elapses between the stopping of the tobacco and complete recovery, depending partly on the degree of blindness and partly on individual peculiarities. Often there is a period of a month or six weeks, or even longer, before improvement begins at all. In many cases where the vision is apparently reduced to much the same extent, there may yet be great differences in the density of the scotoma, and consequently in the extent of the toxic action which has taken place. On the whole, the younger and more healthy the individual, and the smaller the degree of blindness produced, the more ra^iid is the recovery likely to be. The treatment consists in stopping the use of tobacco in any form altogether. Although merely diminishing the amount con- sumed may be sufficient, it is found, as a rule, easier, and it is certainly safer, to give it up altogether. In addition, either inhalation of a few drops of nitrate of amyl or the internal use of trinitrin in small quantities {-^^^ gr.) sometimes appears to hasten recovery. Attention must also be paid to the general health, and an attempt should be made to improve any conditions by which the system is likely to be lowered. The lesion which produces this peculiar form of amblyopia is not known. The regularity in the shape of the scotoma, as well as the complete recovery which so often takes place, render it extremely unlikely that it is a form of retrobulbar neuritis. In undoubted cases of that natu.re, although the central vision is mostly affected, there is rarely either a similar amount of blind- ness in both eyes, or any constancy in the shape of the scotoma, while at the same time there is not infrequently some slight peripheral restriction of the field, and rarely as complete, and certainly by no means as frequent, recovery. It is more pro- bable either that the poisonous effect is exerted on some part of the brain which includes the central terminations of the papillo-macular fibres, or that some limited vasomotor change affects these fibres in some part of their course. Tobacco has been shown to have a direct toxic eftect on nerve cells. Apart from the cases of true retrobulbar neuritis referred to at page 267, there are others which exhibit the symptoms of 420 AMBLYOPIA AND OTHER ANOMALIES OF VISION. a central .scotoma, but which, nevertheless, are not, correctly si)eaking, either cases of central or of toxic amblyopia. It is the existence of such cases, no doul)t, which has led to the mistake of considering toxic amblyopia to be due to inflanmiatory changes in the optic nerve. The true cases of toxic amblyopia have not so far been examined anatomically. Jensen classifies these atypical cases under the following heads : — Stationary scotomatous optic atrophy ; j)rogressive scotomatous optic atroi)hy; bilateral optic neuritis, with central scotoma; unilateral amblyopia, neuritis or atrophy, with central scotoma ; and glaucoma simplex. The most important of these groui)s is the stationary scoto- uiatous ojttic atrophy. Cases of this nature were found to constitute about 25 per cent, of the atypical varieties of central amblyopia, or 7 per cent, or 8 per cent, of all the affections characterised at some time or other in their course by a central scotoma. Of this group Jensen gives the following description : — " It occurs exclusively in young men under the age of 34, usually between the twentieth and twenty-fifth year ; occasionally showing a hereditary tendency, sometimes apparently caused by want of sleep and other weakening factors ; often without any demonstrable cause. The affection begins with considerable amblyopia, which occurs either suddenly or reaches a maximum in the course of a short time, without being accompanied by disturbances of gbneral health ; it develops usually simultaneously in both eyes. " On examination of the field of vision a central scotoma is found of about the same size and form as in amblyopia centralis, but much more complete — white objects, presenting a visual angle of 1 to 2 degrees, disappearing either entirely or becoming very indistinct within its area. Corresponding to this, fixation is uncertain or eccentric. During its course the density of the scotoma, and consequently the central amblyopia, remains as a rule unchanged. " The i)eriphery of the field of vision may jiresent slight anomalies in the colour sense ; rarely complete or i)ermanent red- green blindness. Further, transitory defects of peripheral vision for white objects may arise. As a rule, the perii)hery I'emains normal during the whole course. " Oijhthalmoscopically there is found to be complete atrophy of the pa})illce, and this sometimes very early ; as a rule, it is decided before the lajise of a year. Occasionally there may be a suspicion of a neuritic origin ; on the other hand, a decided HYSTERICAL AI\IBLYOPIA AND AMAUROSIS 421 intra-ocular neuriti.s is never found to precede the atrophy. The prognosis of this affection is bad quoad restitutionem, ))Ut absokitely good quoad ccecitatem." Progressive scotomatous atrophy, which occurs witli about the same frequency as the stationary form, is met with only in men of middle age, rarely if ever before 35. It is to be regarded more as a particular form of development of spinal atrophy than an independent disease, like either central toxic amblyopia or stationary scotomatous atrophy. There is frequently a syphili- tic history, and an association with more or less well-marked premonitory symptoms of tabes dorsalis. The blindness usually comes on in the one eye before the other. The main points in connection with this affection are thus summed up by Jensen : — The affection begins as a central amblyopia, with a central colour scotoma and intact periphery. The scotoma has exactly the same form and degree of satura- tion as that in amblyopia centralis, and, just as is the case in that affection, the defect for white objects can only be discovered for minimal visual angles. During the course of the disease the scotoma retains its size and its relative character. In the periphery, on the other hand, anomalies come on characteristic of progressive atrophy, the boundaries for colours become narrowed centripetally ; and finally, though often very late, those for white also. At this stage the original scotoma is frequently unrecognisable ; the disease runs a course similar to an ordinary progressive atro[»hy, and the prognosis is as bad as other cases of that description. Complete atrophy of the papillae comes on with certainty, and as a rule earlier thaii in the i)receding form ; it may generally be diagnosed at an early stage. Hysterical amblyopia and amaurosis. — Various eye affections occur in connection with hysteria. These may take the form of pareses and other innervational disturbances of the ocular muscles, of asthenopia, of alterations of sensibility and of secretion, and of defects of vision, for which no anatomical cause is discoverable. There may be complete blindness, amaurosis, of one or both eyes. As a rule the blindness is not associated with loss of pupillary reflex. Sometimes, however, the pupils are found not to contract to light. Diagnosis. — Hysterical amaurosis of one eye alone is by far the most commonly met with variety of this curious affection. Such cases are often difficult to distinguish from simulated uni- ocular blindness. This is particularly the case when the pupillary 122 A>riUA'()PIA AND OTHER ANOMALIES OF VISION. reaction to light is normal. The absence of any conscious attempt to deceive the examiner makes it always easy to demonstrate the existence of sight in the " l)lind " eye, and even to determine its acuteness. It is oidy when the jiatient's attention is called to the images on the retina of tlie defective eye alone that these are found to awaken no conscious visual im2)ressions. When used in participation with the other eye, the im})ressions which it receives can be shown to be in no way abnormal. As all lesions situated centrally to the chiasma must necessarily affect both eyes, a lesion which jiroduces a unilateral amaurosis without ophthalmoscopic changes must be located in the optic nerve itself. The differential diagnosis between such a lesion when it causes complete blindness, and unilateral hysterical amaurosis, with loss of pupillary reflex, may present some diffi- culty. For all other cases except retrobulbar neuritis, the history of the onset of the blindness, the concomitant conditions, and the patient's general state would probably always afford sufficient data for a differential diagnosis. Practically, therefore, the difficulty only arises in distinguishing between retrobulbar neuritis which has caused complete blindness, — a comparatively rare occurrence, — and unilateral hysterical amaurosis, with reflex pupillary immobility, a still rarer condition. The differential diagnosis can always be made later, or when recovery has taken place or is progressing. Both may be of sudden onset, but the progress of recovery in the formei", when it does begin, is slower, and the visual functions as they are restored exhibit the characteristic defects of the light sense, and of the relative degrees of disturbance of the central and perii»heral vision. Hysterical amaurosis, though it may last much longer, disappears more suddenly and more comi)letely. It is often cured, too, by methods which are purely suggestive. A long-standing blindness due to retrobulbar neuritis will always be associated with some visible change in the optic disc. Too nuich importance must not be attached in early cases to pain, either spontaneous or pi'oduced by pressure of the eye back into the orbit. This, though usually present in retrobulbar neuritis, may be absent, while it may exist as a pure result of suggestion in hysterical amaurosis. Double hysterical amaurosis is less frequent than the uni- lateral form, and is more often associated with loss or diminution of the pupillary reaction to light. The onset may be sudden, but it is not always so. A gradually increasing blindness, charac- terised by increasing restriction of the field of vision, may jM-ecede the total loss of sight. Recovery, though usually sudden, is also in some cases gradual The duration is variable — from a few HYSTERICAL AMBLYOPIA AND AMAUROSIS. 423 weeks to many months. Double hysterical amaurosis is so characteristic that there can rarely be any difficulty as to diagnosis. The patient, though professedly unable to distinguish light from darkness, does not behave altogether like a blind person. There is, for instance, no stumbling up against objects, and there are many indications that visual impressions are pro- duced, though the i)atient is not clearly conscious of receiving them. The treatment usually relied upon for the cure of hysterical blindness, whether unilateral or bilateral, is the use of subcutane- ous strychnine injections and electricity. There is no doubt that such treatment acts wholly by suggestion. I have been in the habit for years of using pure water alone, injected under the skin of the supraciliary region. This has often a powerful suggestive effect. In many cases one injection effects a com- plete cure, or causes very considerable improvement, which is still further increased by subsequent injections. In some cases the hysterical blindness is not complete. One or both eyes may be merely amhlyojnc. Most frequently the defect in such cases is bilateral. The diagnosis may then be attended with some difficulty. There is always found to be more or less concentric restriction of the field of vision ; and this, if associated with pallor of the optic discs, which is frequently met with where there is a coexisting anaemia, may suggest optic atrophy. In many respects, however, the symptoms, when care- fully examined into, differ from those of atrophy. There is, for instance, usually some, often marked, improvement in the vision when the surrounding illumination is diminished, i.e., in semi- darkness. In atrophy there is only a relative, never an absolute, superiority of the sight under similar conditions. The vision may even be materially worse in semi-darkness. The peripheral colour vision too, in the hysterical cases, is not lost, though it may show irregularities of a curiously atypical nature. The restriction of the field of vision for white is, besides, of the exhaustion type ; that is, it is not constant in amount, and shows much greater differences than in non-hysterical defects of the field according as the test object is moved from centre to peri- phery, or vice versa. Sometimes hysterical amblyopia is associated with local aufesthesia, mainly of the conjunctiva. The condition of hysterical amblyopia is more essentially a neurasthenic one, as a rule, than is the case with hysterical amaurosis. Although it may yield to the same treatment as that recommended above, it is generally more difficult to remove, and may last for many years. Many cases are benefited by massage, 4-24 AMBLYOPIA AND OTHER ANOMALIES OF VISION. isolation, and stuffing, on the lines of the Weir-Mitchell treat- ment. As regards the pathology of hysterical amaurosis, the mere occurrence of unilateral blindness, apart altogether from the fact that the sight is often suddenly and completely recovered, can, I believe, oidy be explained on the assumption that an interruption exists between the centres, to which visual impressions are conveyed, and the psychical mechanism — whatever that may be — which leads to the consciousness of these impressions. Suppression of visual excitations is indeed common even under normal conditions. There is, for instance, a constant so-called struggle taking place between the fields of vision of either eye, which consists of a tiring of the attention alternately to images on parts of the one retina, while the images on corresponding parts of the other retina awaken fully conscious impressions. These, again, fade out in their turn, and give place to renewed consciousness of the retinal excitations of the same region in the fii'st eye. Again, there is the well-known and often complete suppression of images in a squinting eye, which takes place as long as the fixing eye is uncovered, but disappears when the squinting eye is called upon to act alone. There is also the habitual suppression, as a rule, of physiological double images, those of objects not directly fixed or specially engaging one's attention. The hysterical interruptions between the psyche and bodily excitations is therefore similar in many ways to what is con- stantly taking place in health, though its greater persistency and greater completeness, amongst other points by which it is charac- terised, may be difficult to explain. Subjective sensations of light and colour may i)roceed from some irritation of the retina, or may be due to irritations of the visual centres in the brain. It is by no means always easy to detect in any particular case what is their origin. Generally sjjeaking, photo})sia due to retinal irritation is most evident after any ^jrolonged ex^josure of the eye to strong light, or after anything causing fatigue either of the retina or of the body generally, and tends to become less marked or to disappear altogether when the eyes are rested, and therefore especially at night. Photojjsia caused by irritation of the visual centres, on the other hand, is often most distressing at night, and at times when the eyes are not subjected to stimulation from the ordinary objective sources. In some cases of hyjjera^sthesia of the retina, complaints of coloured vision are made. This kind of chroma- topsia is evidently the result of the resjionse to stimuli, which SUBJECTIVE LIGHT AND COLOUR SENSATIONS. 425 would otherwise, on account of their feebleness, be disregarded. Owing, however, to the irritable condition in the retina, or of the more central portions of the visual apparatus, these feeble stimuli evoke sensations, just as hy})erijesthetic individuals may be affected with pains for which little or no objective cause can be detected. A curious form of subjective colour sensation has received a good deal of attention. It is mostly met with in aphakia after cataract extraction, and consists in a more or less constant sen- sation of evei'ything looked at being coloured a vivid blood-red. There is no veiling of the objects, but merely a marked red coloration. The condition, to which the name erythropsia is generally given, has not yet received a satisfactory ex})lanation. It has been ascribed to the dazzling caused by rays of light passing through the coloboma in the iris, or to that along with some fatigue of the retina. As it is met with in other conditions than aphakia and coloboma of the iris, and is not a very common occurrence, it is impossible that these should in themselves be of paramount influence in its production. When it appears after a cataract extraction, it usually does not come on until some time after the operation. It is met with in cases, too, where everything has gone well, and good vision has been obtained. The influence of fatigue or hyj^erajsthesia of the retina in giving rise to coloured vision is undoubted. Some poisons which cause nerve fatigue occasionally also give rise to chromatopsia. Some forms of subjective light sensation are of cerebral origin. One of the most common is that associated with hemicrania. It may begin in different ways, and last for a longer or shorter time, usually after prolonged bodily or mental fatigue, or at a time when there is more or less nervous exhaustion from want of food or sleep ; it suddenly makes its appearance as a dark spot to one side of the field of vision in both eyes. The dark area slowly increases in size, and after some time becomes bordered by scintillating and often coloured, zigzag, margins of greater or less intensity. The configuration of these margins of light often resembles the angular wavy outline of a fortification, and for this reason Airy gave to the affection, from which he himself suffered, the name of teichopsia. The duration of the whole visual disturbance is generally less than half an hour. The appearances fade away from the centre towards the peri- phery, and are most frequently followed by severe headache, often accomimnied by sickness, which lasts for several hours. The central nature of the subjective sensations just described is pretty definitely established by the fact that they may occur, 42G AMRLYOPIA AND OTHER ANOMALIES OF VISION. and indeed this is most frequently the case, in true hemianopic form. This could only be the case when the temixtrary dis- turbance, whether vasomotor or of whatever other nature, was situated centrally with res{)ect to the chiasma. It seems i)rob- al)lc, though, that when the hemianoinc or bilateral character is not marked, the disturbance may in some cases really jtroceed from the retina. I have occasionally met with eccentric negative scotomata in one eye, which aj)pear to have been the result of attacks of this nature. Idiopathic night blindness. — If the eyes are subjected con- tinually, day after day, to a more than usually intense light, such as is reflected from the surface of the sea or plains in tropical climates, or from chalk-pits or snow, there is apt to be set up a condition which has been called idio2:>athic nir/ht blind- ness. The condition arises from the illumination of the whole retina by strong irregularly reflected or scattered light ; other symptoms — namely, a central scotoma, due probably to coagula- tion or some other molecular change in the retina — are caused by the direct action of the light from strong sources of illumination, such as the sun or electric arc. Physiologically there exists a condition in some i-espects allied to night blindness. Thus, if we suddenly enter a darkened room, after our eyes have been exposed to the full light of the day, we experience at first a much greater difficulty in recog- nising objects around us than we do after the lapse of some minutes spent in the comparative darkness. What is called an adaptation of the retina takes place gradually, and is longer in attaining its maximum the more intense has been the illumination to which the eyes were previously subjected. The time neces- sary for comjjlete adaptation is also subject to individual ditterences, depending, amongst other conditions, on the state of the health. Idioi)atliic night ])lindness is more especially liable to occur if, along with the exposure to strong light, the individual is the subject of some weakness — malnutrition, anaemia, scurvy, etc. And although in much the greater number of cases of idiopathic night blindness the primary exciting cause has been found to be referalile to the action of strong light alone, or combined with such conditions as those mentioned, a certain proportion of cases appear to occur as a result of these debilitating circumstances, independently of any abnormal conditions of illumination. Of this nature are the cases described as occurring in women shortly before confinement, and in some cases of cirrhosis of the liver and jaundice. IDIOPATHIC NIGHT BLINDNESS. 427 The affection begins with a condition closely resembling that just described as physiological, but in which the period occu})ied by the adaptation of the retina is very much prolonged. Eventually the adaptation has not time to become complete before the individual is again subjected to the unfavourable conditions, and thus true night blindness comes to be gradually acquired. The difficulties of vision come on during dusk. In rooms, too, which are illuminated by artificial light, unless the illumination is pretty powerful, only objects directly illuminated by the source of light are seen distinctly, the others being more or less indistinct, according to the severity of the symptoms. The condition is one of anaesthesia, or torpor, of the retina, which requires an abnormally strong stimulus to awaken its physiological activity. Other symptoms are found at the same time, depending more or less upon the same cause. The indication for treatment is to withhold light, so as to allow the retina time to recover itself ; and in complying with this indication it is not necessary to keep the patients in absolute darkness, but merely in considerably subdued light, either by the use of dark spectacles or residence in a darkened room, while at the same time attention should be directed, if necessary, to means calculated to improve the general health. Treatment carried out on these lines is always successful, and usually after a very short time. There appears, however, to be a decided tendency to relapse, which should be guarded against l)y a prolongation of the treatment after recovery. In a considerable proportion of cases of idiopathic night blindness there is also a condition of xerosis of the conjunctiva, due to the glare which gives rise to the defect of vision. Idiopathic laight lilindness is accompanied by no marked or constant ophthalmoscopic changes. This absence of ophthal- moscopic changes is also generally characteristic of the somewhat rare condition of congenital night blindness, although it is highly probable that it is closely allied to the degenerative change of the retina known as retinitis pigmentosa, although there is not usually any restriction of the field of vision. There are two distinct retinal end organs, through the medium of which the transformation of physical states into the nervous stimuli leading to vision takes place. One of these merely effects the transfoi-mation of energy which gives rise to the perception of light, and is therefore, so to speak, the end organ for the light sense. The other is capable of ditierentiating the impressions Avhich it receives (or, it may be, the difference of 428 AMBLYOPIA AND OTHER ANOMALIES OF VISION. the impressions formed on the two end organs), so as to lead eventually to a consciousness of the varying intensities and quality of the light rays falling on different parts of the retina, and tlius give rise to the sensations of form and colour. What may be called physiological night l)lindness shows that on exposure to light there is jiroduced a certain degree of exhaustion of the light-sense end organ, so that a certain time "has to elapse before it recovers itself suthciently to be capable of its full delicacy. Abnormal stimuli are cajjable of very much intensi- fying the state of exhaustion, and conse(iuently of prolonging the i»eriod necessary for recovery. Thus it becomes a mere question of the balance between sujjply and demand, so that it is evident that an abnormal degree of exhaustion may be occasioned by either an excessive demand on the one hand, or a defective supply on the other. Whenever there is absence or destruction of the retinal pigment cells, be it congenital or the i-esult of inflammatory or degenerative changes, there night blindness is a more or less marked synqjtom, and this inde- j)endently of whether other elements of the retina are affected or not. Muscae volitantes. — The appearance of shadows in front of the eye may or may not be pathological, according to their nature and the conditions under which they are seen. There are many irregularities in the normal eye which interfere to a slight extent with the passage of the light rays to the retina, and therefore cast shadows on it. These .shadows are, however, mostly too faint to be perceived, owing to the small size of the bodies which throw them, compared to the extent of the surface of light from which rays pass through the pupil. The shadow thrown by one })oint of light is therefore illuminated by the rays proceeding from others. Only such bodies as lie very close to the retina are rendered at all visible by their shadows, and even then are, as a rule, so faint as to escape observation. Many people notice small faint shadows which they project to ditterent distances in front of their eyes when looking at a uniforndy illuminated surface, such as a white cloud or a sheet of white i)aper. These have different shapes : they ai'e annular, or strung together in beaded chains, or have more the appear- ance of irregular shreds of tissue. They are not as a rule fixed, so that while following the movements of the eye they are generally observed to change their position as soon as the eye is brought to rest. On looking upwards, for instance, they appear first to be thrown up along with the eye. On this account these small faint shadows are called muscct volitantes. They are MUSC^ VOLITANTES. 429 caused by the presence in the vitreous chamber of small portions of tissue, probably in most cases embryonic. The fact that these shreds of tissue throw shadows at all, under ordinary circum- stances, shows that they must be at the posterior part of the vitreous. Owing, too, to the free movement of these muscaj, the vitreous must be more or less liquid in the portion occupied by them. As, however, the same muscse can always be seen over and over again, pretty much at the will of the individual, and differ very little in their faintness, the liquid jjortion in which they float must be very narrow. When the rays which enter the eye proceed from a luminous source of a very small extent, such as is the case with those which pass through a pin- hole in a card held close in front of the eye, the musct« appear much darker and more numerous, and other more anteriorly placed irregularities become at the same time visible. It is not easy to draw the line between what may be looked upon as pathological, in respect to the appearance of muscai volitantes, and what is merely physiological. With a small pupil and continued fixation, such as is necessary for writing or drawing on strongly illuminated sheets of white paper, etc., the muscat seldom fail to be observed, though they are more readily seen where there is myopia, and the surface looked at lies beyond the far point. When attention is once drawn to them, they frequently cause considerable annoyance. Yet under such conditions their a})pearance cannot be considered other than physiological. On the other hand, when the conditions are not specially favourable, and they yet cause more or less constant annoyance, they are an indication of the existence of a hyperajsthetic state of the retina, and as such often of some general disturbance, most frequently in connection with the digestive organs. When numerous and changeable, they point to some degree of liquefaction of the posterior part of the vitreous, and are then often associated with the higher degrees of myopia. As long, however, as the bodies casting the shadows are so small as not to be recognisable on ophthalmoscopic examination, they may be generally diagnosed as mere muscae. The complaint of anything appearing to float in front of the eye should, however, always lead one to make a proper objective examination. Colour blindness. — Congenital defects of colour vision occur in from 3 to 4 per cent, of the male i)opulation of civilised countries. Amongst females the ])ercentage is enormously much lower, not indeed one-twentieth of that for males. This com- parative frequency of defects of colour vision has directed 430 AMBLYOPIA AND OTHER ANOMALIES OF VISION. attention to the possible dangers wliicli might result from the employment in our railways and mercantile fleet of individuals unable to distinguish with certainty between red and green, the colours universally used as signals. Accidents directly traceable to mistakes arising from colour confusion must be of extremely rare occurrence, partly because the two signal colours are not amongst those pairs for which the greatest confusion exists, and ])artly because the recognition of the signal does not genei-ally depend u})on one man alone. The possible dangers have cer- taiidy been considerably exaggerated. Still there can be no dou])t that a systematic examination of the colour vision of all persons entering tliese services is desirable. When the possible dangers in connection with colour blind- ness were recognised, it became of importance to discover a means whereby any trace of this anomaly could be speedily detected. Holmgren was the first to devise and employ a method which has proved to be thoroughly practical and ex- })editious. A high degree of achromatopsia may coexist with a tolerably perfect power of naming colours. It is evident, there- fore, that any system based on the statements made by in- dividuals as to the names of colours presented to them must be rejected as impracticable. Of course when the test of naming colours can be made under the same conditions in which they are used as signals, it may safely be emjiloyed as a means of detecting those who should be disqualified. Holmgren adopted the method of comjMrison between colours which to the normal eye are different. I/olm(jren's test for colour blindness. — The individual ex- amined is asked to pick out from amongst a large number of different coloured wools those which apjiear most like one particular shade placed before him. From the way in which the test is executed by different in- dividuals, it can at once be seen whether they are colour con- fusers or not. Those with normal vision, provided they are possessed of a certain amount of intelligence, are not long in selecting the few shades which most nearly resemble the pattern given them to match. A colour confuser, on the other hand, soon makes a sufficient number of nustakes to reveal his defect. Holmgren begins with light green, and when mistakes are made with this, proceeds with some shade of rose — that is, a colour between red and blue. This is very well suited for this purpose, as it can at once be seen, from the colours with which it is con- founded, in which direction the defect lies. What is the actual condition of the sense of colour in those COLOUR BLINDNESS. 431 who are colour blind 1 In the first place, there can be no doubt that an individual who is blind for one particular hue is at the same time blind for its complement. Again, although he fails to distinguish between many different colours, yet he is only actually blind for two particular hues which are complementary, and the slightest change in Avhich is capable of giving i-ise to a colour impression. Only one neutral line is usually to be found in tlie spec- trum of the colour blind. The reason for this is, that in the immense majority of cases the complementary hue to the green hue for which they are insensitive is not found in the spectrum. It is in fact one of the purplish hues which are invisible as homogeneous light. If we take any red, orange, yellow, or green sector, and com- bine the impression received from it with that from a blue pigment by rotation on a disc, we find that the proportions of any of these with the blue, which is necessary to produce a neutral colour sensation, varies in different cases of colour blindness — that is to say, different cases are blind for different non-saturated hues, which, owing to their mixture with white light, are impure, and, owing to the absorption of light by the pigments, are wanting in brightness. In all probability, therefore, there are a great number of forms of colour blindness, though they bear a close resemblance to each other, corresponding in general to blindness for certain rose and green hues. The term colour blindness is in such general use that it would seem inadvisable to reject it altogether. Nevertheless, it is obvious that such a term as colour confusion would be more applicable to all cases except those of total colour blindness. We know the primary cause of colour sensations, and the final result. Of the intermediary stages in the process, namely, the manner in which the definite physical conditions become changed into definite psychical impressions, little is known. It is known, of course, that the first transformation takes place in the retina, and that the brain receives the retinal impressions, which are conveyed to it along the optic nerves. But we do not know what is the nature of the transformation that takes place in the retina, or of the resulting primary excitation in the brain which awakens the consciousness of colour. It is natural that there should be speculation as to the manner in which the inter- mediary process is accomplished. One can readily understand, too, that the fact that it is possible to obtain all colours from three or more colours variously combined, taken along with the 432 AMBLYOPIA AND OTHER ANOMALIES OF VISION. doctrine of specific nerve energies of Johannes Miiller, should create a strong leaning towards " fundamental " colour hypo- theses. Apart, however, from this, there does not ai)i^ar to be an)' reason for making such an assumption ; there is, in fact, no evidence of the existence of primary colours either in the physical basis or in the final consciousness of colours ; in other words, in all we know anything about. A question which naturally suggests itself is. Where is the defect in colour blindness 1 Is it in the retina, in the optic nerve, or in the brain ? 80 far as pathological conditions go, there is never any great disproportion met with between the colour and form sense defects in any case of purely retinal disease — that is to say, disease involving only the percipient layers of the retina ; the changes in coloiu- vision to which such alterations give rise are similar to what is caused by dimin- ished illumination : colours are seen much as they are in semi- darkness. On the other hand, colour vision appears to be disproportionately reduced, as compared with vision for form, in all cases where the conducting mechanism is implicated. This is most marked where it may be assumed that there is a general lowering of the conductibility of contiguous groups of optic nerve fibres, as in the various forms of amblyopia affecting the centres of the retina (toxic amblyopia, retrobulbar neuritis). It is in cerebral changes, however, that the greatest propor- tionate defects in colour vision are found — alterations in the retinal elements and optic nerves pi'oduce a lowering of colour })erception, not merely red-green confusion, though this, especi- ally in the latter cases, is often most marked, corresponding to the less perfect development of red-green vision at some parts of the normal retina. In the case of changes localised in the brain, this tolerably equal distribution, or impaired vision for all colours, is also what is most frequently met with (in the so-called hemiachromatopsia, for instance), but cases have been recorded in which a purely red-green confusion has been acquired. The experience of pathology would render it probable, then, that the abnormality in colour l)lindness is a central cerebral one and not retinal, i.e., that the retina of the colour blind responds in the same manner to the ordinary physical stimuli, but that for some reason or other the psychical result is an abnormal one. This is all the more proliable from the fact that under altogether normal conditions of colour vision the same physical stimulus does not necessarily give rise to the same colour impression. This is seen in the well-known phenomenon of simultaneous contrast. Hemianopia. — Symmetrical defects in the fields of vision are HOMONYMOUS HEMIANOPIA. 433 most commonly caused by lesions in the chiasma, the optic tracts, and their more central connections. If the defects lie to the same side in both eyes, — that is, inwards in one and out- wards in the other, — the condition is that which is now generally called homonymous hemianopia. Homonymous hemianopia may be to the right or left, and partial or complete, just as we have complete and partial, right or left, hemiplegia. It may or may not be associated with hemiplegia. If the case be recent and uncomplicated, there is no ajipearance of atrophy of the nerves. The line of demarcation between the blind and seeing portions of the field is usually sharp and regular ; when the hemianopia is complete, it is a line coinciding (for peripheral portions of the field, at anyrate) nearly, if not exactly, with the vertical through Fig. 170. — Fields of visiou from a case of homonymous hemianopia, in which vision was lost in the left lower quadrant of each field. the point of fixation. The lesion producing homonymous hemi- anopia has been found to occupy different situations, namely, the optic tract, basal ganglia, fibres of Gratiolet, and the cortex of the brain in the occipital lobe. The experiments of Munk, and the results of post-mortem examination, have definitely established the existence of an unilateral source of innervation for corresponding halves of both retinse. In the cases where the lesion has been cortical, it has either been one occupying a portion of the grey matter of the occipital lobe, or one pressing on the white matter "with which it is in connection. Important data in connection with the localising of lesions which have led to hemianopia are afforded by the consideration 28 434 AMBLYOPIA AND OTHER ANOMALIES OF VISION. of the concomitant symptoms, as well as by the extent and con- figuration of the blind area. In all the cases which I have seen of so-called hemiachromatopsia, — that is, cases in which the half-blindness appears to be only for colours, — I have been able, by testing with very small white objects at a distance, to de- monstrate that the form-sense has also been defective over the same area. Indeed, the results of careful subjective examination in these as in other cases point altogether more to the prob- ability of colour vision being due to a subtle differentiation of light impressions, than to any im})ression made upon other centres than those in which the consciousness of form is evoked. When the hemianopia is partial, the defect is generally, though not always, of equal extent in both eyes. Fig. 171. — Fields of vision from a case of temporal hemianopia. The hemianopia may in rare instances be limited to corre- sponding insular portions in the homonymous halves of the two visual fields. Bi-temporal hemianopia. — The other form in which a half- blindness may present itself is often called crossed hemianopia, though the term bi-temporal is preferable. It is of considerably rarer occurrence than the homonymous form. The arrangement of the optic nerve fibres renders the localisa- tion of the lesion producing bi-temporal hemianopia a very simple process. The symptoms are always caused by more or less complete destruction of the fibres of the ventral surface of the chiasma. This situation is that occupied by the fibres which cross from the optic nerve of the one side to the optic BITEMPORAL HEMIANOPIA. 435 tract of the other. Bi-temporal hemianopia i.s therefore con- chisive evidence of disease involving the chiasma. It is difficult to form any idea of the frequency of this variety of hemianopia. Owing to the nature of the defect, leaving as it does a much larger field for both eyes than the homonymous form, the patient does not as a rule complain of blindness to one side. The other symptoms, too — amblyopia, ophthalmoscopic changes, etc. — are sufficiently marked to engage the whole atten- tion of anyone who does not make a practice of examining the peripheral vision. Besides, comparatively few, no doubt, of the cases which have been observed have been published. Mauthner believes that they constitute about 1 per cent, of all cases of hemianopia, while Ftirster's estimate is 23 per cent. ; the actual percentage probably lies about midway between these extremes. It is obviously a disease of too rare occurrence to furnish even approximately correct statistics from the practice of any single observer, however extensive his experience. A good many cases have come under my own observation, and in three of them the diagnosis — in two cases an aneurysm, and in the remaining one a tumour pressing on the chiasma — was confirmed on post- mortem examination. The line of demarcation between the blind or defective portion of the field and the normal one is rarely as sharp or as vertical as in the homonymous form. The prognosis is not so good either, most cases going on to complete blindness. Some cases may remain stationary, or recover to some extent. A sudden onset, with subsequent partial recovery, or, as sometimes happens, blindness of one or both eyes followed by temporal hemianopia, is suggestive of an apoplexy in the neighbourhood of the chiasma. A slight degree of intermittence in the symptoms — slight im- provement on certain days — is probably indicative of aneurysm. Repeated attacks of bi-temporal blindness, lasting several days at a time, and then recovered from, point, again, to acute intracranial pressure from some cause or other. SECTION 11. CHAPTER XVII. ERRORS OF REFRACTION AND ACCOMMODATION. In considering the eye at rest, and not exerting the power which it has of altering its state of refraction, or, in other words, of accommodating for the distance from which rays proceed, many points may be perfectly well explained by looking upon it as consisting of only one dense transparent medium, bounded by only one surface, instead of, as is actually the case, being a very complex organ, with a number of differently refracting media. When the eye is in a state of rest, and not exerting any of its power of accommodation, i.e. when its refracting power is at its lowest, one of three conditions must be represented in every case — (1) The principal focus (or the focus of rays which meet the eye parallel to each other, and therefore the focus of a plane wave disturbance) coincides exactly with the most sensitive portion of the centre of the retina ; (2) the principal focus lies in front of the most sensitive portion of the centre of the retina ; and (3) the principal focus lies behind the most sensitive point of the centre of the retina. In the first case, the eye is said to be enimetrojnc, in the second mi/opic, and in the third h^/per- nietropic ; and these conditions of refraction are called respect- ively emmetropia, inyopia, and hyp>ermetropia. Emmetropia in the true sense is exceedingly rare. Very slight deviations in the direction of either myopia or hypermetropia are common, however ; so that the eyes which are practically emmetropic are common. It is evident that as there are three elements on which the state of refraction depends, — namely, the length of the antero- posterior axis of the eye, the curvature of the refracting or dioptric media of the eye, and the refracting power of these media, — the conditions on which myopia or hypermetropia depend might be abnormal conditions of all or any of these elements. As a matter of fact many cases of myopia and hypermetropia 440 ERRORS OF REFRACTION, ETC. Fig. 172. — Showing the complete focussing of parallel rays in the case of emmetropia, E, and incomplete focussing in hyper- metropia, H, and myopia, M. do occur which are wholly or mainly caused l)y sonic abnor- mality in each of these directions. Thus we have axial myopia or hypermetropia, due to a too long or too short antero-posterior axis of the eye (Fig. 172); curvative myopia or hypermetropia, caused by too great or too little curvature (Fig. 173) ; and index myopia or hypermetropia, as the result of too great or too feeble refracting power. The emmetropic eye alone, when at rest, is focussed for parallel rays. Rays diverging from a point in front of the eye and suffering the same amount of refraction would meet behind the retina, whilst rays converg- ing to a point behind the eye, and also refracted to the same extent, would meet in front of the retina. It will be evident now that a myopic eye {i.e. one in which the retina lies behind the principal focus of the refracting media) is, in a state of rest, focussed only for rays diverging from some point at a particular finite distance in front of it, and also that a hypermetropic eye (i.e. one in which the retina lies in front of the principal focus of the refracting media) is, in a state of rest, focussed only for rays which converge towards a particular point lying at a finite distance behind it. Therefore the static refraction in emmetropia leads to the focuss- ing of parallel rays on the retina, the static refraction in 7nyo2na to the focussing of diverg- ing rays on the retina, and the static refraction in hypermetro2)ia to the focussing of converghig rays on tlie retina. The greater the divergence or convergence of the rays which is required in any case, in order that they may be focussed on the retina, the greater is evidently the error of refraction. The measurement of that error, or what is called the degree of ame- tropia, is given by the distance from the anterior part of the eye from which the rays focussed on the retina diverge, or towards Fig. 173. — Showing the longer refracting power of the more highly curved cornea (continu- ous line). EMMETROPIA, MYOPIA, AND HYPERMETROPIA. 441 which they converge. The smaller this distance is, tlie greater is the ametropia. This distance is also called the distance to the far x>oint of the eye. The far point is therefore that point from which rays which meet on the retina of the unaccom- modated eye diverge, or to which they converge before entering the eye. The far point in myopia lies consequently at a finite distance in front of the eye, whilst in hypermetropia it lies at a finite distance behind the eye. In the case of emmetropia the far point lies at an infinite distance from the eye, because only then are the rays which proceed from a point truly parallel. Practically, emmetropia is considered to exist in any case where the far point lies not nearer than 6 metres in front of or behind the eye. In the condition of static refraction, then, an emmetropic eye obtains a clear image of objects at a distance. Fig. 174. — Different forms of convex and concave splierical leu.se.s, as seen in section. A myopic eye in the same condition obtains a clear image of objects which lie at the distance of its far point. To a hyper- metropic eye at rest, however, no objects, near or distant, are seen with the utmost degree of clearness, as rays from every real object must diverge, and the hypermetropic eye is only focussed for converging rays. Sjiherical lenses. — The substances of which lenses, used for most optical purposes, are made are glass and ci-ystal. Certain names are given to lenses, according to the shape of their two surfaces. When both are convex the lens is called biconvex. When both are concave, it is said to be biconcave. When one surface is plane, the lens is either iilano-convex or j'lf^i'no-concave. Two other forms of spherical lenses are made, in which the one sur- face is convex and the other concave, but with different radii of curvature. When the convex surface has the greatest curvature, i.e. the smallest radius, the lens is a convex meniscus (Fig. 174, c); 442 ERRORS OF REFRACTION, ETC. wlicn tlie concave surface has the greatest curvature or least radius, the lens is called a concave meniscus (Fig. 174,/). The principal focus (the focus of parallel rays) in the case of a convex lens lies on the other side of it from that from which the rays proceed, and is real — that is to say, the rays actually are collected ; and although, owing to sjjherical aberration, they do not meet in a mathematical point, still the more axial ones are practically focussed. Convex lenses are therefore called positive or plus lenses. The principal focus, again, of a concave lens lies on the same side of the lens as that from which the rays proceed, and is virtual — that is to say, the rays do not actually, but only appar- ently, proceed from the focal point. Concave lenses are there- fore called negative or mimis lenses. Use of spherical lenses in ametropia. — We have seen that in myopia the eye is too powerfully refracting relatively to the position of the retina, i.e., its collecting power is too great. This may be rectified by putting in front of it a concave or negative lens, the strength of which is just sufficient to counter- act that portion of the collective power of the refractive media of the eye at rest which is in excess of what is required to focus rays coming from distant points on the retina. On the other hand, in hypermetropia the collecting power of the refracting media of the eye is insufficient, and this again may be corrected by putting in front of the eye at rest a convex or positive lens, the strength of which is just sufficient to supplement the defective amount. The concave lens which corrects the myopia in any particular case, or the convex glass which corrects any particular case of hypermetropia, is that one which, placed at a convenient dis- tance in front of the eye, produces in the state of static refraction of the eye the most accurate focussing of rays from a distant point (parallel rays) on the retina. The glass in each case must be one ivhose focal distance equals its distance (measut'ed from its position in front of the eye) from tliefar point of the eye. It must, therefore, have a shorter focus the nearer the far point lies to the eye. In other words, the higher the ametropia, the stronger must be the correcting lens. It also follows from the above definition of the correcting glass, that the nearer it lies to the far point of the eye the stronger it must be. In myopia the far point lies at a finite distance in front of the eye, therefore the strength of a concave glass, in order to correct any definite degree of myopia, must be greater the farther USE OF SPHERICAL LENSES IN AMETROPIA. 443 it is placed from the eye. From this it follows that the effect of a concave glass of definite strength on myopia is lueakened hy removing it from, and strengthened by approximating it to, the eye. In hypermetropia the far point lies at a finite distance behind the eye, consequently the convex glass which corrects any definite amount of hypermetropia must be weaker the farther it is placed Fig. 175. — Action of a concave lens in front of the eye, causing parallel rays to enter the eye as if proceeding from a finite point in front of it. from the eye. From this, too, it follows that the effect of a convex glass of definite strength on hypermetropia is strengthened hy removing it from, and iveakened by approxin\/xting it to, the eye. The nature of the correction effected by a lens placed in front of an ametropic eye is therefore to give such a direction to Fig. 176. — Showing action of a convex lens placed in front of the eye, causing parallel rays to enter the eye as if directed to a point at a Knite distance behind the eye. parallel rays that they converge towards, or appear to diverge from, the far point of the eye. This is seen in Figs. 175 and 176, which represent respectively the correction of myopia by means of a concave lens, and of hypermetropia by means of a convex lens. Numberiruj of lenses. — Lenses are numbered according to the length of their focus : a focal length, 1 metre, being taken as 444 ERRORS OF REFRACTION, ETC. the unit, positive or negative. A lens of this })ower is called a lens of 1 dioptre, or shortly, I D. One only half the refracting l)ower of a 1 D lens, and which has therefore a focal distance of 2 metres, is numbered 0"50, and one of twice the power, i.e., with a focal distance of ^ metre, 2'0, or 2 D, and so on. Lenses used as spectacles seldom require to be stronger than 20 dioptres, positive or negative — that is, 20 times as strong as a +1-0 or -1-0 lens. Every unit of difference corresponds, then, to an equal in- crease or decrease in refracting power. The usual trial cases contain the following spherical lenses, Ijoth plus and minus : — 0-25 2-25 .^-50 13-0 0-50 2-50 6-0 14-0 0-75 2-75 7-0 15-0 1-0 3-0 8-0 16-0 1-25 3-50 9-0 17-0 1-50 4-0 10-0 18-0 1-75 4-50 11-0 19-0 2-0 5-0 12-0 20-0 In all, sixty-four different spherical lenses. In most cases there are two of each number. Sui)posing, now, an eye to be focussed for parallel rays, either owing to its own formation or as the result of an optical correc- tion such as we have considered, it will, when at rest, receive no distinct image of objects near at hand. All that is necessary, however, in order that the retinal image of any object at any distance should be distinct, is that the rays proceeding from it should be given such a direction as if they came from a distance, i.e., that the greater or less divergence of such rays should be converted into i)arallelism. This could obviously be done by placing a convex lens in front of the eye, the focus of which lens coincided with the position of the ol)ject, and whose strength would therefore have to be less the nearer it lay to the eye. It will now be apparent that should the eye not of itself be so formed as to focus parallel rays on the retina, the glass which renders this possil)le, and which therefore either diminishes or increases its refractive power, must be subtracted from or added to the lens otherwise required to give a distinct image of an object at any particular distance. Thus, if a myopic individual requires a — 2*0 lens to sec a distant object distinctly, he will require, as long as the refracting })ower of the eye remains un- altered, a lens of 4 •0—2-0, or-h2'0, to focus distinctly an object at a little more than \ metre distant. On the other hand, ACCOMMODATION. 445 a hypermetropic individual who can only see distant objects distinctly with a + 2 '0 lens, would require one of 4 '0 + 2 "0, or + 6'0, to focus an object of a little more than \ metre distance. A weaker lens is therefore required for the focussing of near objects in myopia ; and a stronger lens in hypernietrojna than is required in enimetrojna. Accommodation. So far we have supposed the eye to be constantly exhibiting the same degree of refraction, that which results from the relative positions and curvatures of its various refractive media when uninfluenced by any circumstance by which these may be modified. The eye is, however, able by a muscular effort to increase the strength of its refracting power, or, in other words, to accommodate itself for the vision of near objects. This is effected by an increase in curvature of the surfaces, and conse- c[uent lengthening of the antero-posterior diameter, of the crys- talline lens. It is mainly the central portion of the anterior surface whose curvature increases. The effect of this is tanta- mount to adding a convex meniscus to the crystalline lens, the refractive strength of which meniscus gives the measure of accommodation, so that we talk of 2, 3, 4, 10, or 14 dioptres of accommodation, according to the power of this addition ; that is to say, that when, for instance, an eye alters its accommodation from that required for seeing an object at a distance to that re- quired for focussing accurately one at J^ metre, it has altered its power of refraction to exactly the extent which would correspond to the placing of a 10-dioptres glass lens (whose thickness was neglected) immediately in contact with the crystalline lens. The eye is then said to have exerted 10 dioptres of accommodation. We have seen that the point for which the eye at rest is focussed is called the far point. The point, on the other hand, for which the eye is adapted when exerting its full power of accommodation — that is to say, the point which in the strongest state of refraction of the eye has its conjugate focus on the retina — is called the near point. The focal strength, again, of that addition to the lens which brings the adaptation from the far to the near point measures the amplitude of accommodation in each case. Thus, if A denote the value in dioptres of the accommodative change, and F and N respectively the values of the lenses in dioptres whose focal distances measured from the eye would coincide with the far and near points of the eye, we have A = X - F. 446 ERRORS OF REFRACTION, ETC. It is evident that ecjual ampfitudes of accommodation may coexist with ditiereut positions of far and near points. Thus there is the same change in refractive jwwer i^roduced by an addition of 5 dioptres within an eye focussed for parallel rays, as there is by the same addition of 5 diojjtres in the case where it is already focussed for a distance of i metre. Yet the linear distance between the two i)oints focussed for differs very con- siderably, reaching, in the first case, from an infinite distance to 20 cms., or 8 in., from the eye ; in the second, from 20 cms. to 10 cms., a linear difference of 4 in. In both cases A, the amplitude of accommodation, =5"0 in the first, because N = 5"0 and F = ; and in the second, because N = 10 and F = 5'0. The accommodation is said to be j^ositive when the eye, from being focussed for a more distant object, is adapted for the vision of a nearer one ; negative, when the change in accommodation takes place in the opposite direction, and the refractive power of the eye is diminished. A positive change in accommodation is occasioned by a muscular effort ; a negative change, on the other hand, is a result of a cessation of more or less of the muscular contraction, so that the eye in a state of rest, as far as muscular effort is concerned, is focussed for its far point. The amplitude of accommodation, depending, as it does, on the extent to which the curvature changes take place in the crystalline lens, in response to the action of the ciliary muscle, is influenced by the consistency of the lens substance, as well as by the functional activity of the ciliary muscle or the nerves which supply that muscle. Diminution in the amplitude of accommodation, due to changes which take place in the lens, is physiological in so far as such diminution slowly and gradually takes place during life ; probably not beginning, however, till after the first few years of childhood. Although, therefore, not absolutely identical, there exists a very similar amplitude of accommodation in all individuals of the same age, being less the older the individual, until it completely disappears, and no power remains of altering the refraction of the eye. The linear distance separating the far and near points — or, shortly, the position of the amjjlitiide of accommodation — depends, on the other hand, upon the state of refraction of the eye ; but it, too, may change with age, owing to the tendency which the condition of refraction has to alter at different times, more especially up to the jieriod of full growth, and after the age of 60. The most favourable position of the amplitude of accommoda- tion is that which admits of the focussing of objects through the greatest distance. This is what occurs in emmetropia, and in ACCOMMODATION. 447 cases of ametropia where the ametropia is fully corrected. In hypermetropia, when the amplitude of accommodatiou is con- siderable, and the hypermetropia not of high degree, it is also favourable, i.e., although a certain portion is required for the adaptation of the eye for distant vision, there still remains a sufficient amount to enable the eye to focus objects at a distance near enough for all practical purposes. The position of the amplitude of accommodation is most unfavourable in myoi)ia, as in no state of active or passive refraction is it possible for the unaided eye to get properly Fig. 177. — Diagram showing position of lens, etc., in eye at rest and in accommodated eye. — After FucHS. (The true manner in which the curvature is altered is not shown in this figure.) distinct images of di-stant objects, so that its accommodative range only serves the purpose of adapting it for vision of near objects, — the linear distance corresponding to the .same accom- modative range being of course smaller, and consequently less serviceable, the higher the degree of the myopia. Indeed, even when the myopia is by no means considerable, say 4 dioptres in amount, the amplitude of accommodation which the eye possesses is, unless the error be corrected, of little practical use, as few objects require to be looked at, at a shorter distance than \ metre. Myopia of that degree, at a time of life when there exists an accommodation of say 10 dioptres, is associated with us ERRORS OF REFRACTIOX, ETC. greater inconvenience, so far as the i)Ossibility of receiving distinct images of objects at different distances is concerned, than a liypernietroi)ia of the same degree, and with the same accommodative power, 6 dioptres of which, after 4 dioptres have been employed to adapt the eye for i)arallel rays, cover the distance from the most distant objects to those oidy ^ metre from the ej'c. It will now be readily understood that more is usually effected by the correction of ametrojna than the mere optical adaptation of the unaccommodated eye for the focussing of jiarallel rays. In all cases where a fair amplitude of accommodation still remains, its position is thereby at the same time displaced, so as to become as favourable as possible. The contraction of the pupil, which occurs along with efforts at accommodation and convergence of the visual axis, is of more or less service in extending the range of distinct vision. On account of the smallness of the pupil, and consequent diminution in the size of the circles of diffusion, the position at which ordinary sized print, such as that used in newspapers, can be seen, lies considerably within the real near point, or that for which the eye is actually focussed. The determination of the amplitude of accommodation (A) in a large number of individuals of different ages was made by Bonders, Avho obtained an average for different ages, from which he plotted a curve (Fig. 178) in which the ordinates represent the age and the abscissae, the corresponding amplitude of accommo- dation measured in dioptres. This curve enables us to see at a glance what is the average amplitude accommodation for any age, and conversely gives for a certain amplitude of accommoda- tion the average age at which it is found. The curve gives, too, the actual position of the near point corresponding to any age, supposing the eye to be emmetropic. By merely displacing the curve upwards or do^\^lwards, the position of the near point at the same age (and indicated in the same way by the number of the dioptre lens having an equivalent focal length) for any degree of myopia or hypermetropia is obviously also given, as it is clear that this must be got by merely adding or subtracting the value of the far-point lens. Thus in myopia of 5*0 dioptres, according to the diagram at 10 and 20 years of age, the distance of the near point from the eye would be respectively represented by the focal distance of a lens of 14-0 + 5-0 =19-0 and lO'O 4- 5-0 = 15-0 dioptres,— r.e., it would be in the first case j\ instead of jx of a metre distant from the eye (a linear difference of about 19 mm.), and in the ACCOMMODATION. 449 second ^t instead of J„ metre from the eye (a linear ditference of over 33 mm.). And whilst in ametropia the near point has usually at about the age of 64 receded so as to be infinitely distant, an individual whose myopia at that age Avas 5*0 would still have a near point rather within i of a metre from the eye. Again, taking a case of hypermetropia S'O; we should have the average near point at ten and twenty years represented respectively by lenses 14-0 -5-0 = 9-0 and 10-0-5-0 = 5. Before forty the near point would have receded to infinity, as by that time in emmetropia it is represented by rather less than 5'0, 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 \ \ \N \, S s. \ \ N. s N s. N, s. S S X ~i N F ' F ■■ ^. N ^ L, -^^ Fig. 178. — Douders' curve of range of accommodatiou. — After Nagel. and in the degree of hypermetropia we are considering would be rather less than 5-0 — 5 '0 = 0. Practically, it has to be remembered that whilst the curve of Fig. 178 gives the average, we may frequently find not incon- siderable real or apparent differences, more especially in the direction of the range being greater than is there given. It has to be remembered that the near point — and this refers more especially to young people — may not always appear the same in the same case, as much depends on the effort exerted to increase the refractive i)ower, and the greatest possible effort can only be momentarily maintained. 29 450 ERRORS OF REFRACTION, ETC. One of the .simplest practical methods of finding the position of the near point in any case is to determine the str(jngest concave glass with which the individual can see distinctly small print (of a size corresponding at a definite distance from the eye to something approaching the limit of his visual acuity) ; or, where the near point lies beyond the distance at which the print is held, the weakest convex lens with which it can be seen. In order to do so he has, of course, to add as it were ai\ equivalent convex lens to his eye in order to overcome the concave one placed in front of it, so that the strength of that addition, and consequently the point for Avhich the eye is focussed when exerting its full amount of accommodation, i.e., its near point, can be readily calculated from the strength of the concave lens and its distance froni the eye. This is seen in Fig. 179, where the meniscus-shaped portion of the Fig. 179. — Showing the niainier in which the aution of a concave lens can lie overcome by alteration in the curvature of the crys- talline lens. crystalline lens is that which counteracts the effect of the concave lens. In order to exert the greatest possible amount of accommo- dative power, most people have to bring about a degree of con- vergence of their visual axes which is greatly in excess of that which would direct the lines of vision on the nearest point thus accommodated for. What is called the absolute near point can therefore, as a rule, only be attained by the sacrifice of binocular vision. The binocular near jwint and the binocular amplitude of accommodation have been distinguished by Donders from the absolute. It is seldom that the difference between the two amounts to anything of practical importance. Donders also pointed out the importance of what he has called the relative amplitude of accommodation. This may be looked upon as that which is at the disposal of the individual for any particular degree of convergence ; that is, given any point on which the visual axes converge, the diflereuce between the ACCOMMODATION. 451 farthest and tlie nearest point for which the eyes can be accom- modated without changing the i)oint of fixation. The relative amplitude of accommodation varies for different distances of fixation ; but the practical importance to be attached to it is usually limited to the amount and disposition of the range which exists for the reading distance. That portion of the relative amplitude which consists of the difference between accommodation for the distance fixed, and the nearest point for which accommodation, with that degree of convergence, is pos- sible, is called the 2^ositive portion of the relative am})litude of accommodation. That portion, on the other hand, which is the difference between the degree of accommodation for the point fixed and the farthest point which, under the circumstances, can be distinctly focussed for, is called the negative portion. The positive portion is determined by the strongest concave glasses which can be overcome, and the negative by the strongest con- vex glasses which can be overcome without any change in convergence. It is generally considered that only when the positive portion is at least as great as the negative is the distance one • for which accommodation can be maintained for any length of time without giving rise to pain or discomfort, or, in other words, to Avhat is called accommodative asthenopia. In some cases, however, there is a considerably greater than normal negative relative accommo- dative range, so that probably the proportion between the negative and positive portions is of less importance, as affecting the capability of maintaining the necessary degree of accommo- dation for the working distance, than the actual amount of the positive portion, which should at least equal 2 "50 to 3'0 dioptres. The direction of fixation appears also to be of some influence on the amplitude of relative accommodation. It is not always the same, for instance, in looking down as on looking up at equally distant objects. The difference in this respect is subject, too, to individual variation. Fig. 180 is Bonders' curve of relative accommodation in the case of an emmetrope aged fifteen. The equally distant hori- zontal lines represent intervals of I'O dioptre of accommodation, so that the point where they cut the curve gives the amount in dioptres of accommodation exerted. The vertical lines repre- sent the angles of convergence made by the two visual axes corresponding to the distances for which the eyes are accom- modated. The numbering is according to Nagel's metre angle notation, which is based on exactly the same system as that 452 ERRORS OF REFRACTION, ETC. explained for the metrical numbering of lenses. According to this notation, the angle which the visual axis of each eye makes when a point in the middle line is fixed, with the direction they have when fixing a distant point straight in front of them, is expressed as the reciprocal value of the distance from the eye to the nearer point measured in metres, or fractions of a metre. Thus, if the distance fixed he ^ metre, the convergence is said to be 3 metre angles in amount; if yV of a metre, distance 10 metre angles ; and so on. Similarly, the difference in the degrees ~7 / / y / / / / / / * / / y / / / / / / / / / * N / -^ — — -7" ■— ^ P* .' ^ -^ / / ^ k-* / y / / ,/■ ^ / > y / y' f-' / / r / / |x / y / / ^ y ^ / / / / / / / ^ / ,'' ^i-i— 1 A fiL " I 2 3 4 5 6 7 8 9 lO II 12 13 14 IS 16 17 18 19 20 Fig. 180. of convergence between the direction required for fixation of a point ^ of a metre and another y\; of a metre from each eye equals 7 metre angles. The normal or ideal relation between convergence and ac- commodation, in which for any number of dioptres of accom- modation exerted a similar number of metre angles of converg- ence takes place, is represented by the diagonal line. This relation can obviously only exist when the refraction is emme- tropic, and the position of rest of the visual axes parallelism, or where a definite degree of hypermetropia or myopia is asso- ACCOMMODATION. 453 ciated with a corresponding amount of divergence or convergence of the axes in the state of rest. The position of any point on the curve above the diagonal I'epresents the positive, that of any point below the diagonal the negative, portion of the relative accommodation for the degree of convergence represented by the vertical line which passes through it. In the case for which the curve is plotted, we see that binocular vision has been impossible for a point N' lying nearer than between I and ^^J metre from the eyes, and that although 18-metre angles of con- vergence were possible, this did not result in an absolute near point closer than yjj metre. The curve also shows that e^■en although it has been impossible to accommodate for the nearest points for which the eyes were converged, still a certain range of relative accommodation remained up to the greatest possible convergence. Here, too, we see that this positive portion of the relative accommodation range has equalled the negative up to a convergence of 5-metre angles, so that the individual has been in the position of being able to maintain the amount of accom- modation necessary for reading at i of a metre, or say 8 inches, without any inconvenience. If the myopic or hypermetropic individual were situated exactly as the emmetropic in respect to the association of the convergent and accommodative movements, — that is, if his zero point of convergence corresponded to his zero point of accom- modation, — it is evident that when the ametropia was at all considerable he would have to sacrifice binocular vision in order to see distinctly. We have only to displace the diagonal line downwards in the case of myopia, and upwards in the case of hypermetropia, to see at a glance Avhat the requirements of these states of refraction are, and how they become more difficult of attainment, on the supposition made, the higher the degree of ametropia. Thus the lower line represents the requirements of a case of myopia of 5"0 dioptres ; it shows that up to a 5-nietre angle of convergence no accommodation is required, whilst for 8-metre angles of convergence, for instance, only 3"0 dio})tres of accommodation are necessary. Again, a glance at the upper dotted line of the diagram, which represents the requirements of a case of hypermetropia of 5"0 dioptres, will show that up to 5*0 dioptres of accommodative effort the visual axes must remain parallel, whilst for 8*0 dioptres of accommodation only 3-metre angles of convergence are required. The actual state of matters in cases of ametro})ia is, however, not so bad as it would Ije did the conditions as they exist in emmetropia hold good in the manner we have supposed. There 454 ERRORS OF REFRACTION, ETC. is a great difference in this respect in different cases, a difference which depends partly on the extent to which the nature of the association of the two impulses to convergence and accommoda- tion differs from that which we have looked upon as normal or ideal, and partly on the range of relative acconnnodation. A full correction of the ametropia in any case, l)y which, as we have seen, the position of the am})litude of accommodation is altered to what t»htains in emmetropia, frequently gives rise to discomfort, owing to its introducing at the same time a less favoui'able situation of the existing relation between accommo- dation and convergence. This is more esi)ecially the case when the correction is made in adult life. On the other hand, a full or partial correction often relieves the asthenopia which an unsuitable relation in the associated impulses occasions. A question which naturally suggests itself in connection with accommodation is, as to whether or not the two eyes can be accommodated to different extents at the same time. For objects seen in the middle line, and where the refraction is the same in the two eyes, an unequal degree of accommodation would not be i-equired in order that the utmost distinctness of the images on both retince should result. On the other hand, when the object fixed is to the one side, and not far from the eyes, or where there is unequal refraction in the two eyes (what is called anuometropia), an equal amount of accommodation would obviously not permit of absolutely distinct images being obtained in both eyes. What then hai)pens under these cir- cumstances'? Do the two eyes accommodate unequally, so as, when the difference is not too great, an equally distinct image is obtained in each eye 1 Or do they accommodate to the same extent, and if so, is one properly focussed, or does the accom- modation take place in both for an intermediate distance 1 By holding a weak prism in front of one eye, with the base directed ui)wards or downwards, whilst a single line of small print or other suitable te.st-object is fixed either well to the one side, or in the case of anisometropia in front, of the face, it will in- variably be found that the image corresponding to the one eye is perfectly distinct, whereas that which belongs to the other is more or less blurred, according to circumstances. In anisometropia it is usually the eye for which the accom- modative effort required for the distance fixed is smallest that is properly focussed. Therefore, when one eye is myopic and the other emmetropic, the myoi)ic one is correctly focussed ; when one is emmetropic and the other hypermetropic, the PRESBYOPIA. 455 emmetropic one ; and so on. In the fixation of objects lying to one side, it seems generally to be the eye which lies nearest to the object which determines the amount of accommodation to be exerted. In both cases much dei)ends on the state of visual acuity of either eye, and on which of the two retinal images the individual is in the habit of unconsciously directing most attention, but the relation existing between the accommo- dative and convergent impulses is no doubt also of influence in this respect. The contraction of the pupil which takes place along with accommodation is a muscular movement associated, in all prob- ability, with both the accommodative and convergent move- ments. Presbyopia. When the near point has receded beyond 22 cms., or a little more (about 9"), which the curve in Fig. 178 shows takes place at or about the age of 45 in emmetropes, a difficulty is experi- enced in reading small print, more especially when badly illumi- nated, or in working at anything which requires to be taken near to the eyes in order to give a large enough image to be seen distinctly. To this defect in vision the name of jjreshyopia, or "old sight," is given. When an individual becomes presbyopic he is obliged to wear convex glasses in order to see distinctly even momentarily any- thing which he has to take within about 9 inches of his eyes. For objects, too, at a somewhat greater distance from the eyes, corres})onding to the ordinary reading distance, he has too small a reserve of accommodative power to continue focussing without undue effort. The glass which has to be worn under these circumstances should be of such a strength as to bring the near point to between 23 and 24 cms. from the eyes, i.e., it should supplement the defect in accommodation to such an extent as to make the combined strength of the accommodative change (measured from the existing adaj)tation for a distance) and the glass equal to that of a lens of 4 "50 jtlaced in front of the eye. In emmetropia, then, it must supplement the amplitude of accommodation by just the amount that it falls short of 4"r)0 dioptres. In hypermetropia, although there is for the same age the same average anq)litude of accommodation, its jiosition is un- favourable for near vision, and the hypermetrope becomes presbyopic at a time when he possesses a greater amplitude 456 ERRORS OF REFRACTION, ETC. tlian 4"50 dioptres, and therefore at an earlier age than is the case in ennuetropia. For niyoi)ic individuals the reverse holds good — the position of their range of accommodation is favourable to near vision ; the near point is consequently longer in receding to the extent which renders the aid of a convex glass necessary, so that presbyopia is later in making its appearance in myopia than in emmetropia. From Fig. 178 it will be seen that the originally emmetropic eye becomes, as a rule, more or less hypermetropic after the age of 65 ; this is represented by the dip of the far-point curve, so that after that age stronger glasses than 4 '50 may be required. The cause of this senile hypermetropia is similar to that which gives rise to the advancing diminution in the ampli- tude of accommodation, namely, the sclerosis of the lens. This produces not only a loss of elasticity, but also a change in the refractive indices of the different layers of the lens. The layers become more and more dense, and eventually equal in their refractive power the central or nuclear portion. The result of this is to diminish the refractive power of the lens as a whole, and therefore of the eye. The glass required for the correction of the presbyopia in a hypermetropic or myopic individual is at once determined from that required for an emmetrope of the same age by merely adding to or subtracting from it that which corrects the ametropia. Thus, if an emmetrope required + 3 '0, a hyper- metroi)e of 2 dioptres of the same age Avould, as a rule, require + .5'0, and a myope of the same amount + I'O. Measurement of Ametropia. The determination of the degree of myopia or hypermetropia may be made both subjectively and objectively. With a little intelligence and good acuteness of vision, on the part of the individual tested, the subjective method is the most rapid and accurate. It is only, therefore, when either of these factors is deficient, or when the patient tries for any puri)ose to deceive, that an objective test is called for. The mbjective test is made by determining the glass required to give the best vision at a distance. The distance should be at least 5, jireferably 6, metres, and the test objects be tyi)es or figures graduated in size according to the method first adopted by Snellen. The presence of accommodative power renders it possible for MEASUREMENT OF AMETROPIA. 457 people to see equally well (though not so comfortably) with different strengths of glasses. This circumstance must always he kept in mind ivhilst makimj a subjective test under the ordinary conditions. In order to get rid of the disturbing element of accommodation, many ophthalmic surgeons are in the habit of using a mydriatic. This is an altogether unnecessary incon- venience to which to put the individual examined. It not only unduly prolongs the examination, but often (owing to rays which pass through the more irregular portions of the corneal periphery being included in those which are transmitted through the widely dilated pupil) may lead to a wrong estimation of the refraction. Personally, I have never found it necessary to use a mydriatic for this purpose. In the case of myopia the degree of normal refraction is given by the xreahest glass with which the individual obtains his best vision (provided there is not any marked defect in his acuity). Stronger glasses do not necessarily diminish the acute- ness of his vision, because they may be, and in the case of young myopes almost invariably are, neutralised or overcome by an accommodative change in the crystalline lens. In the case of hypermetropia, accommodation plays a still more important part. We have seen that this condition of refraction, when not exceeding in amount the amplitude of accommodation at the disposal of the individual, may be corrected by accommodation. This is, as a rule, what is done, more or less of the amplitude of accommodation being brought into play in order to permit of distinct vision. The desire to see anything distinctly, which is almost constantly present when surrounding objects are sufficiently illuminated, is habitually associated, then, in hypermetropes with an accommodative eftbrt. If, therefore, we put a convex glass in front of the eye, we can only expect to find that with it the hypermetrope, by relaxing a corresponding amount of accommodation, will maintain the same visual acuity which he had without it. If, then, a convex lens either 2JVoduces an iiajtrovement in vision or does not render dis- tant objects less distinct, the eye must be hypermetroinc. But we cannot, as a rule, determine the full degree of hyper- metropia by means of the convex glass held in front of the eye, in the same way as has been explained can be done with a concave glass in the case of myopia. The reason of this is that the accommodation brought into play in order to overcome the refractive error cannot be altogether relaxed during attempts at fixation, and thus a portion of the hypermetropia remains latent. The total degree of hypermetropia (H<) is divided then into a 458 ERRORS OF REFRACTION, ETC. portion which is latent (H/), and a portion which is manifest {\im) ; or H< = H/ + Hm. The proi)ortion between the latent and manifest portions of tlie hypermetropia varies with the age of the individual, and also to some extent with the degree of the total hyi)ermetropia. The older the individual the smaller is the proportion which remains latent, so that after a certain age — from 40 to 45 — the whole amount is manifest. The lower degrees, too, are more persistently corrected by accommodative efforts than the higher. The stronf/est glass, therefore, with which the individual retains the full degree of visual acuity which he possesses is the measure of his manifest hypermetrojna. A determination of the whole hypermetropia subjectively is only possible when the accommodation is paralysed. A close approximation to it may be got by an objective examination. When the fundus of an eye is illuminated by means of the ophthalmoscope, the rays which are reflected from any point in it proceed after refraction through the dioptric media, as if they diverged from or converged towards some other point, the image of the first. If the eye be hyi)ermetropic, and the defect not corrected by accommodation, they will diverge as if from a point behind the eye ; if myopic, they will converge to a point in front of it. The distance of this, the far point, measures in either case the degree of the ametropia. In the emmetropic eye the rays reflected from a point in the retina pass after refraction through the dioptric media, not in the shape of a cone but as a cylinder, all the rays being [)arallel to the one which passes from the point on the retina to the nodal point. No image of any extent of the fundus of the emmetropic eye is formed in the observer's eye, unless the ophthalmoscope mirror be held very close up to the eye examined. If held any distance off, nothing is seen but a red reflection. The reason of this is that the cylindrical bundles of rays from the points at either extremity of a portion of the retina cross between the eyes of the observer and observed, and thus do not pass through the aperture of the mirror, so that what is seen is merely a collection of rays from a very small area, not sufficiently exten- sive to be recognised in structure. The larger the pupil of the eye examined the greater is the area from which rays pass into the obsei'ver's eye, consequently the larger is the portion of the fundus which he can see at the same time ; and, given a definite size of o])ject, — such, for instance, as the optic disc, — the farther away it can be seen. A distinct image of a portion of the fundus of a myopic eye MEASUREMENT OF AMETROPIA. 459 is formed in the observer's eye if the ophthahnoscope mirror be held at a distance greater than that of the far point of the myopic eye by at least the distance of the observer's near point. The amount of the fundus whose image is thus seen depends on the size of the pupil and on the degree of the myopia. The larger the pupil the greater the image with a given degree of myopia. Again, the higher the myopia the greater is the portion of the fundus seen with a given size of pupil. When the observer's eye is nearer the eye examined than its far point, it receives rays from a lai'ger portion of the fundus, but, unless his eye be hypermetropic, these do not give the observer a clear image. A distinct image of a portion of the fundus of a hypermetropic eye is received by an observer reflecting light into the eye from some distance. The amount of the fundus seen depends on his distance from the eye, on the size of the pupil, and the degree of the hypermetropia. It increases as the distance separating the two eyes diminishes, and as the pupil and degree of hyper- metropia increase. If, therefore, the observer at some distance from the eye receives with the ophthalmoscope mirror alone a tolerably clear view of any part of the fundus, such as the vessels or optic disc, the eye examined must be ametropic. If the patient move the eye slowly in any direction, the image seen will appear to move, and the direction of the movement at once shows whether the fault in refraction is one of myopia or hypermetropia. In myopia the image will move in the same direction as the eyes ; in hypermetroi)ia, in the opposite direction. If, instead of the patient moving his eye, the observer moves his own head, still keeping the fundus in view, then in myopia the image moves in an opposite direction to that of the observer's head, while in hypermetropia it moves in the same direction. The movement here observed is a parallactic one, due to the position of the images of the fundus with resiject to the pupil. As the pupil lies behind the image in myo[)ia, and in front of it in hypermetropia, their apparent movement is in opposite directions, the more distant object always appearing to move with the mirror. The indications afforded by the mirror alone, or by the indirect method of ophthalmoscopic examination, are only just sufficient to enable one to diagnose whether the refraction is greater or less thiin normal. An aiiproximation may be made to the degree of the ametropia in various ways. Two methods are in general use for thus m) ERRORS OF REFRACTION, ETC. estimating the refraction, namely, the examination of the fundus oculi with the oi>hthahnoscope by the direct method and the shadow test. Objective estiinatiu)i. of refraction hy direct oplithalnioacojnc examination. — In order to be able to estimate the refraction of another individual, the observer must, in the first place, know the Fig. 181. — To illustrate the estimation of refraction by direct ophthaliiioscopie examiuation. state of his own refraction. The glass which corrects this, when it is not emmetropic, is brought in front of the aperture of the ()l)lithalnioscoi»e, and forms the starting-point from which any other glass which may be required to obtain a distinct image of the patient's fundus is calculated, as representing the one which in the position which it occupies in front of the patient's eye MEASUREMENT OF AMETROPIA. 461 approximately corrects his ametropia. Thus, if the details of the fundus appear perfectly distinct to the observer when ex- amining with the ophthalmoscope close up to the patient's eye, the accommodation of both eyes being relaxed, and either without any glass intervening between his own eye and the aperture in the mirror, or with that glass which corrects an existing error in his own refraction, then the patient must be approximately emmetropic, as the rays proceeding from any part of the fundus are then all parallel to that which is directed to the nodal point, and such a parallel bundle of rays must, after refraction through the observer's eye, or through the system of correcting lens and eye, meet at some point on his retina. In Fig. 181, E, the course of the rays is shown in the case of emmetropia of both observer and patient. When the patient is not emraetro})ic, it is necessary for the observer, always supposing that he keeps his accommodation relaxed, to bring such a lens behind the ophthalmoscope as shall focus his own eye for the far point of his patient. Thus, if the patient be myopic, he must render his own eye hyper- metropic to an equivalent extent, as the rays which meet his eye from any point on the fundus of the patient are convergent instead of parallel, and therefore meet at a point in front of his retina. The concave lens necessary to effect this is that which will correct the patient's myopia, the determination of the degree of which can therefore be made in this way. This is represented at M, Fig. 181. If the patient be hypermetropic, the observer must bring in front of the ophthalmoscope aperture a convex lens, whose focal distance corresponds to that of the patient's far point, in order that the divergent rays from all points on the patient's retina may be rendered parallel, and thus be brought again to a i)oint on the retina of the observer. The strength of the lens which effects this is, of course, the measure of the degree of the hyper- metropia when corrected in the position occupied by it in front of the eye. This is re^jresented in Fig. 181, H. The, estimation of refraction hy means of the shadow test is made by observing the direction of motion of the red reHection got by throwing light into the eye from an ophthalmoscope mirror held at some distance and rotated slightly in a definite direction, while lenses of known strength are placed in front of the eye. It has been called the shadow test because attention is directed more to the dark shadow which borders the illumi- nated area than to the area itself. The examination is made in the following way. The room 162 ERRORS OF REFRACTION, ETC. must l)c darkoied. From the source of light — wliich may be lihiccd either at the side of the i)atient and shaded from him, or iiniiiediately over his head — a beam is reflected by means of an oiihthalmoscope mirror. The mirror may l)e either i)lane or concave ; but, other circumstances being similar, the movements made by the shadow are in opposite directions, according as one or other is used. Thus, if in any case the shadow moves in the same direction as that in which a })lane mirror is rotated, it will move in the opposite direction to the rotation of a concave one. The appearances met with when a concave mirror is em})loyed will be described. The observer should be seated 1 metre from the i)aticnt. If, on slightly rotating the mirror, not too quickly, in a horizontal plane, the shadow ajipears to move in the same direction as the rotation, or " with the mirror," then the refrac- tion is myopic. If it move in the direction oi)posite to that in which the mirror is rotated, or "against the mirror," the refrac- tion is either emmetro[)ic, hypermetropic, or only slightly myopic. By putting lenses in front of the eye — concave if the direction of the shadow indicates myopia, convex if it indicates hyi)ermetropia — we may arrive at a strength of the lens in eitlier case which reverses the direction of the shadow, and therefore get a first a}»proximation to the lens which is required for the correction of the ametropia, if it exists. The weakest lens which reverses the movement, fi'om being with the mirror to being against the niirror, is not quite the measure of the myopia. On the other hand, the weakest lens which reverses the movement, from being against tlie mirror to being with it, is rather higher than that required to correct the existing hyijer- metropia. If the lens is not higher than -f- 1 "0, the refraction cannot be far from emmetropic. The shadow test has received many names, e.r/., keratoscopy, retinoscoi)y, koroscopy, skiascoi)y. Hypermetropia. This is the most common condition of refraction, and is more common at an early age than in adult life. The eyes of new- born infants are almost invariably hy2)ermetropic. In hyper- metropia there is a disproportion between the length of the eye and the curvature of the cornea, and it is not easy to say whether at birth the hypermetropia is an axial or curvature hyper- metropia. The hypermetropia which persists after adult life has been attained is, however, almost always axial, and not only is the antero-posterior axis abnormally short, but the whole HYPERMETROPIA. 463 eye is often smaller than normal. In the higher degrees, indeed, there appears to be a kind of arrest of develoj^ment, and this is often associated with a defective visual acuity. The acuity of vision in the lower degrees of hypermetropia is usually normal. Hypermetropes in whom the defect in refraction is not corrected, are necessarily obliged to exert their power of accom- modation more constantly, and to a greater extent, than is the case with emmetropes. This is frequently associated Avith a feeling of tiredness or pain, mostly referred to the supraciliary region, which comes on when the eyes have been used for a longer or shorter time for reading or other work near at hand, and is known as accomniodative asfheiiojna. The circumstances which influence the occurrence and severity of this symptom are — (1) The degree of the hypermetropia; (2) the age of the individual ; and (3) the state of the general health. The higher the degree of hypermetropia, so long as there is a possibility of accommodating at all for the distance at which the objects engaging attention are placed, the more likely is there to be asthenopia ; and again, with the same degree, troubles are more frequent the older the individual, because the amplitude of accommodation diminishes with age. Difficulties, too, which are overcome without much eflbrt in a state of robust health, give rise to a much more conscious effort in conditions of physical and mental weakness or fatigue ; consequently accommodative asthenopia is, ceteris jm^Wus, more frequently complained of in the anajmic and delicate than in the robust and active. When the amplitude of accommodation is much restricted after middle age, or owing to paresis of accommodation, the difficulties of a hypermetrope are increased, as he then not only has a difficulty in seeing distinctly objects near at hand, but has also defective vision for a distance. This condition, in Avhich the hypermetropia is not corrected by accommodation, is called absolute hypermetropia. An apparent divergence of the eyes is often noticeable in hypermetropes. This is due to the visual axis of the hyper- metropic eye passing considerably to the inner side of the optic axis. In a large percentage of cases of convergent strabismus there is found to be hypermetropia. The connection between hyper- metropia and convergent squint is explained in the chapter on strabismus. Many hypermetropes only occasionally use their power of accommodation to correct their distant vision, and thus do not constantly keep up the state of contraction of the ciliary muscle. They are in the habit of contenting themselves with 46-t ERllOHS OF HEFFvACTION, ETC. an imperfect image of surrounding objects, unless anything should specially attract their attention. Owing to the tendency, which exists in by far the greatest proportion of eyes, for the antero- posterior axis to become gradually elongated during the })eriod of growth, an existing liypermctrojiia is often diminished in degree or converted into enimctropia, and even myopia, by the time an individual has ceased to grow. The treatment of hypermetroi»ia consists in the wearing of convex glasses. The strength I'cquired is that which corrects the manifest portion of the hypermetropia. The convex glass chosen is therefore the strongest with which the individual re- tains the full visual acuity he possesses. If asthenopia be com- plained of, they should be worn constantly, for a distance and near. When there is no asthenopia, and the hypermetropia not of high degree relatively to the age of the individual, it is generally sufficient, if glasses be used at all, to make use of them for near work. They may then be ordered of a rather greater strength than that which corresponds to the manifest hyi>er- metropia. Hypermetropes should be seen from time to time, at intervals say of a year, after they have first begun to wear the prescribed glasses, in order to see whether there is any change in the amount of their manifest hypermetroi)ia. In many cases there is none during the years of growing, at anyrate, though as they get older the degree corrected constitutes often more and more of the total amount. In others there is soon found to be a further amount of the hypermetropia which is manifest, and which, when discovered, should be corrected. Again, in some children there is a pretty rapid diminution of the hyjiermetropia, so that after some time the glasses ordered have become too strong, and weaker ones should be substituted for them. Hypermetropes have often small })upils, owing to the con- traction of the pupil which takes place along with that of the ciliary muscle. As has already been explained, the hypermetropia which occurs in old age is an iiidex hypermetropia, produced by sclerosis in the crystalline lens. There are no ophthalmoscopic appearances specially charac- teristic of hypermetropia. Sometimes there is an evident hy})erajmia, with some (usually slight) swelling of the optic papilla?. In a small proportion a white crescent is seen to the temporal side of the disc, due to the opening in the choroid, through which the optic nerve passes, being larger than the MYOPIA. 465 sclerotic o})ening ; but this ai)pearance is more frequently associ- ated with the abnormally elongated eye. Myopia. Myopia is more frequent, and is met with in higher degrees, in adult life than during the period of growth. It is hardly ever congenital, and usually first makes its appearance after the age of 10. It has a tendency to increase up till the time when the individual is fully grown, after which, in the vast majority of cases, it remains stationary. Progressive myopia, at a later period of life, appears to be more common in w'omen than in men. Myopia is mostly axial, and though not congenital, the tendency to the elongated shape of the eye is undoubtedly inherited. Except in the higher degrees (above 8 to 9 D) the visual acuity is in most cases normal, and the eye in every respect healthy. The visual acuity for near objects is gener- ally greater in the uncoiTected myopic eye than in the accom- modated hypermetropic or emmetropic eye. When uncorrected, the vision for distant objects is indistinct, and the more so the higher the degree of myopia. Uncorrected myopes, however, with the same degree of refractive error, do not by any means see equally badly at a distance, as much depends on the size of the pupil, and more perhaps on the habit, which some possess to a much greater degree than others, of making much out of a bad image. Thus we invariably find that those, otherwise intelligent and observant, who are not in the habit of wearing concave glasses make more of the images — i.e., arrive unconsciously at a more perfect mental elaboration of the images they receive of distant objects — than those who are constantly in the habit of receiving distinct images by the aid of correcting glasses. The fraction representing the visual acuity is greater, too, the nearer the test object lies to the far point of the eye, and this is most noticeable in cases where the degree of the myopia is only moderate. Thus while V tested at 20 ft. may be only Y^, it may be §■ to ^ at 10 ft., and J to ^ at 5 ft. In this way the defective vision caused by myopia dijfers from amblyopia. The jjupils in myopia are usually larger than normal, so that the defect of distant vision is in this way increased. The reason of this is, no doubt, the comparative infrequency of in- nervation to contraction of the ciliary muscle. There being seldom any necessity for it, accommodation is not brought into 4GG EIUIORS OF REFRACTION, ETC. j)lay so much as in the case of the other coiulitions of refraction. The ciliary muscle in myopic eyes is often found to be feebly develoi)ed, the circular fibres more esi^ecially being conspicuous by their absence. Myoi)es have often a sleepy appearance, owing to the im- perfect manner in which they see surrounding objects at any distance. For the same reason, there is often a poking of the head forwards, a shyness of character, and a more marked fond- ness for reading and study than is evinced, on the whole, by those the state of whose refraction enables them to see more distinctly surrounding objects or individuals. Hence in great measure it is that the number of myopes in the learned pi'ofessions, and amongst those engaged in occupations necessitating near vision, is greater than is to be found amongst those who are otherwise occupied. There is sometimes an apparent convergent squint in myopes, due to the circumstance that the visual axes then pass slightly to the outer side of the optic axes. Myopia is sometimes also the result of disease ; and when this is the case, it as a rule rapidly assumes a high degree, and often eventually leads to blindness. In some cases of myopia the absence of accommodative im- pulses leads to an insufficiency of the power of convergence, which is intimately associated with accommodation. This in- sufficiency of convergence is often wrongly called insufficiency of the interni. The same imiiediment in the performance of con- vergent movements is apt, under circumstances of unequal acuity of vision in the two eyes, to give rise to divergent squint, a form of squint more frequently associated Avith myopia than with other conditions of refraction. An ophthalmoscopic appearance is met with in the myopic eye, which although not absolutely characteristic of this state of refraction, is more frequently connected with it than with such as are due to a less elongated form of the antero-posterior axis. The appearance is that of a white patch, usually concentric in shaj^e, immediately to the outer side of the entrance of the optic nerve. In some cases it is seen above or below instead of to the temporal side. This patch is due to an absence of some, or all, of the layers of the choroid in this situation, and a consequent reflection of more or less light by the white sclera. Its size bears no invariable relation to the degree of myopia. When large — i.e., when its breadth is nearly equal to or exceeds the dia- meter of the papilla, and more especially when it extends all round the nerve — it is always associated with the higher degrees, MYOPIA. 467 and must, too, be looked upon as pathological, and suggestive of progressive myopia. The white myopic crescent, as it is called, is generally bordered by pigment where it meets with the edge of the normal choroid, and there is often at the same time an appearance of the central vessels of the nerve being pushed to the inner side, an appearance which is due to the edge of the aperture in the choroid coming closer up to the nerve than it does when there is no crescent on the other side. In many cases of the higher degrees of myopia Avhere the abnormal elongation is due to a staphylomatous jDrotrusion of the back part of the eye, and consequently the myopia is the result of disease, the changes round the nerve are produced not only by displacement of the choroidal aperture, but by degenera- tive changes of an inflammatory nature as well. At the same time, other changes are met with in the region of the macula lutea. These, notwithstanding the existence of more or less metamorphopsia, i.e. the appearance of distortion of objects seen, are at first not very evident, but as the myopia progresses they usually make their appearance as a more or less indefinite irregularity in the retinal pigment layer at the macula, or it may be small whitish or yellowish-white sj^ots in the same region. At later stages a ring-shaped pigmentation, surrounding a more or less degenerated area, is often seen ; and in extreme cases actual patches of considerable size may occupy the site of the macula, or the retina immediately surrounding it. In about 10 per cent, of all cases of myopia the condition is met with in one eye alone. In such cases the degree of myopia is rarely more than 4 or 5 dioptres. Occasionally, also, there may be only slight myopia in the one eye, and a much higher, or even excessive, degree in the other. The treatment of myopia consists, in the first place (and in all cases where it is merely a type of refraction, and not the manifestation of any disease), in wearing concave glasses. The glasses worn should, as a rule, be those which fully correct the myopia. Owing to the power of accommodation, stronger glasses than those required do not necessarily render the vision less dis- tinct. The rule is therefore to give the iceakest concave glasses which admit of the full visual acuity which the individual has. When prescribed early in life, the correcting glasses may be worn both for distant and near vision without causing any discomfort, and with the advantage of rendering unnecessary the same degree of convergence of the visual axes which the uncorrected myope of any considerable degree is in the habit of exerting when reading. This is not always the case if glasses [GS ERROIIS OF REFllACTION, ETC. are first worn later in life, and it is sometimes necessary, even before the age at which presbyopia shows itself in emmetrojies, to use weaker glasses for reading. This is jjroliably owing to the unusual relation which is all at once introduced between the convergent and accommodative movements. Thus, whilst the individual has hitherto been converging up to the distance of his far point without exerting any acconimodation, he has now all at once to associate with every degree of convergence a similar degree of accommodation. The diminishing effect of the concave glasses, which is partly real and partly apparent, though disagreeable at first, generally very soon passes off, and in the lower degrees of myopia is indeed often not noticed at all. The same may be said of the distortion of larger objects to which glasses give rise ; indeed, it is most remarkable that so little notice should usually be taken of this. In progressive myoi»ia due to disease great care should be taken to avoid any undue convergence of the axes — reading in a bad light, exposure to strong light, stooping, etc., anything in fact which might be likely to determine or keep up a congestion of the eyes. At the same time attention should be directed to the general health. Counter-irritation and local blood-letting are also recommended, and may sometimes be of use. The question as to the etiologi/ and pathology of myopia is one of no little difficulty, and one on w^hicli many different views are entertained. The greater frequency of this state of refraction in some countries compared with others equally civilised, and the almost complete absence of it in uncivilised countries, has natur- ally given rise to the idea that it is associated with some of the conditions of civilised life which are more prevalent in some parts than others. No doubt certain circumstances to some ex- tent influence the increase of myopia during the period of growth. Eyes at that time ai)pear to have a tendency to adapt themselves to the conditions under which they are used. The conditions of school life, for instance, are very apt to lead to an increase of an existing myopia, or even to determine this state of refraction in eyes in which the tendency to elongation exists. How exactly this so-called school myopia arises has never been satisfactorily explained. But great confusion has been introduced by a failure to discriminate between the cases of short sight due to disease, and those much more numerous cases which are the expression of a particular type, and are no more to be looked upon as patho- logical than is, for instance, the attainment of a greater than average stature. MYOPIA. 4G9 Tlie fate of many cases of the malignant forms being assumed as the possible fate of all cases of myopia has given rise to all sorts of theories, supported either by statistics, anatomy, or experi- ment, to account for the progression which takes place during the period of growth, and to a corresponding number of more or less unpractical proposals as to how such progression is to be stopped. Attention has naturally been directed to schools, from which statistics — mainly from America, Gerinany, France, and Switzerland — have clearly shown that the percentage of cases, as well as the degree, of short sight increases regulai'ly from the lowest to the highest forms, the increase being greater amongst the children of the better-class schools than amongst charity- school children. Some good has undoubtedly arisen from this agitation, as it has led to much-needed reforms in foreign schools, in the way of better ventilation, better light, better desks, and, more particularly, greater attention being shown to physical training. Not only have different conditions associated with the use of the eyes at near distances been supposed to give rise to myo})ia, but many different explanations of the manner in which any particular condition brings about the elongation on which the myo[)ia depends have been advanced. To take but one example : excessive convergence of the visual axes, which is looked upon by many as the main cause of the development and advance of myoi)ia, is by some explained as acting by causing a dragging on the optic nerves ; by others, by introducing either increased intraocular tension or a stasis in the circulation, resulting from the pressure of the external recti on the eyeballs. Some believe, too, that this may occur without the coexistence of any actual diseased condition of the coats of the eye at the region, which becomes gradually more and more distended ; whilst others hold that this is impossible, except on the assumption, for which they ffnd more or less histological evidence, of a low form of inflam- matory tissue change. The myopic crescent has often, too, been •taken to be the forerunner of a staphyloma posticum, whereas there is good reason to believe that in most cases it is of no pathological importance whatever. The position of our knowledge with regard to myopia a})pcars to me to be as follows : — We know that this state of refraction comparatively rarely begins much before puberty, that it in- creases regularly with age till the period of full growth has been arrived at. We know, further, that this increase takes jjlace independently of schooling ; and the numerous statistics which have yet been published, though strongly suggestive of a direct 470 ERRORS OF REFRACTION, ETC. iiiHuencc of school work on the progression, have by no means clearly established the extent of such an influence. There is no reason why any pathological condition should be inferred in eyes which yield to this influence ; as it has been abundantly shoASTi, and is the experience of anyone who has jtaid attention to this (juestion, that notwithstanding the continuance of the same conditions as to reading, etc., in after life, the rule is for the myopia to remain stationary. The natural conclusion is, then, 9011 \ \ \ j -\, ,^ \ / '^. k. k- Hyper- » -metropia' S 3 HI 3 D.M yopii Fig. 182. — Curve representing the frequency of diH'erent degrees of refractive anomalies in , the literate, clerks, artists, tailors, etc.; , the illiterate, labourers, etc. — After TsCHEUNiNG, from examination of conscripts. that if an influence is proved to exist at all, it is the expression merely of an adaptation of the eye to the work it is mostly called on to perform, occurring at a time of life when such adaptations are possible. One point of importance is, that although the educated classes present a far larger pro])ortion of myopic individuals than the uneducated, still amongst the latter there is found to be an equally large proportion of the higher and more complicated cases. This is shown diagrammatically in the accompanying MYOPIA. 471 figure. This fact is also an indirect evidence in favour of the ordinary myopia being in no sense a disease. The malignant form is relatively much rarer than the statistics of any ophthalmic clinic would lead one to suppose, owing to the circumstance that so many myopes of the ordinary type, having no retinal defect, readily find out how to correct their refraction themselves. We find, too, an undoubted here- ditary predisposition to ordinary myopia, whereas little or none seems to exist in connection with the malignant form. This heredity is markedly visible in America, where, notwithstanding the subjection to the same conditions of school life, there is a great difference in the percentage of myopes found amongst the children of German, English, or Irish parentage. It appears to be a pretty definitely established rule that those countries which have longest been civilised have the largest proportion of myopes, and that, too, to a large extent independently of whether or not at the present time they are the most advanced in an educational point of view. Evidently, then, the adaptation that has taken place in the eyes to the requirements of civilisation, in the way of early education, has been slow, and probably influenced more by heredity than by individual application. We have no statistics to show in how far the condition of short sight has acted on the choice of a profession, and consequently those which demonstrate the preponderance of myopia in the learned professions are far from being conclusive, as they are generally taken to be, of the influence of study in causing or increasing it. In a society in which the possession of a certain amount of education is a requirement of the higher classes, the ordinary laws of natural selection must be at work, causing a preponderance of myoi>ia in these classes. On the other hand, in savage communities, where so much depends on the possession of good distant vision, the same laws must act towards preventing the perpetuation of, or even actually exterminating, the myopic type. The higher degrees of hypermetropia appear also not to be met with in savage comniunities. The same law of the survival of the fittest would act against the perpetuation of this type as well. A considerable difficulty, it must be confessed, is now and then experienced in determining whether, in any particuhir case, the myopia is to be looked ui)on as pathological or not, so that it is not always easy to draw a sharp line between the two forms. This is not to be wondered at, as the short sight at tlie time of examination may be the only symptom of what is actually a disease. Whatever be the cause of the probable increase in the exist- 472 ERRORS OF REFR ACTION, ETC. inii tendoiK-y to imtgre.ssion in myopic eyes during tlie jteriod of growth, Nvhifh application of the eyes to near ol^jects i)roduces, there can be little doubt that the proi)er treatment consists in wearing the correcting lenses. Any operative treatment, such as tenotomy of the external recti, paracentesis of the cornea, sclerotomy, etc., the indication for which rests entirely on theo- retical considerations, is altogether unjustifiable in the present state of our knowledge. Astigmatism. In the conditions of refraction hitherto discussed, we have seen that the rays proceeding from an external point met, after refraction through the transparent media of the eye, at some other point, or as nearly at a point as the existence of spherical and chromatic aberration admitted ; that is to say, the refraction w^as symmetrical round the optic axis. When this is not the case, the eye is said to be astigmatic (a, a-Tiyfj.a), the name first given to this condition of refraction by Whewell. Two forms of astigmatism occur. The want of symmetry may be of such a nature that the greatest refraction of the rays takes place in one plane, whilst the least refraction takes place in the plane at right angles to that plane, the I'efraction in inter- mediate planes being regularly intermediate in amount (though different in nature). This is what is called regular astigmatism. The cause is mostly a difference in the curvature of different meridians of the cornea, a difference which may be congenital or acquired. In highly astigmatic eyes the whole globe appears more or less evidently flattened in one direction, so that the deformity does not exist in the cornea alone. Regular astig- matism admits to a certain extent of optical correction. When the meridians of gi'eatest and least refraction are not at right angles to each other, there is what is called irregular astignuitism. This condition rarely admits of oi)tical correction to any extent, and is caused by an irregularity in the curvature of cornea or lens. Although the amount of astigmatism is always the same for the same differences in the focal i)Ower of the two principal meridians, the character of a regular astigmatism differs accord- ing to the position that the foci of rays refracted through the meridians of greatest and least curvature have with respect to the retina. If the focus of either coincides with the layer of percipient elements of the retina, the astigmatism is what is called simple. Two forms of simple astigmatism occur: (1) ASTIGMATI8]\r. 473 Simple myopic astierrnetr<>pic astiEFP..\rTTOX, ETC. point, from the t-yo of tlu' individual examined. The observer .sees through the hole in the di.se the image of the concentric rings, which, if there be no astigmatism, apjiear circular. But if the curvature of the cornea is different in different directions, the rings are elliptical in .shape, the long axis, or the direction in which the image is largest, corresponding with that of least, the short with that of greatest, corneal curvature. If there be irregular corneal astigmatism, it is very beautifully seen by the use of .such a disc. Care must of course be taken, in using Placido's disc, that its j)Iane is at right angles both to the vertical and horizontal planes through the eye. It is usually the vertical meridian, or some meridian not far from the vertical on either side, Avhich is most curved, and there foi'e the most myopic or least hypermetropic meridian ; but the exceptions to this rule are numerous. Sometimes the ametropic meridians lie at right angles to each other in the two eyes, so that much of the visual defect in either eye is made up for when both eyes are used together. The amount of astigma- tism is more frequently different in the two eyes. Though often the same, it is not always exactly so for near as for di.stant vi.sion. Even when, as is most frequently the ca.se, no appreciable difference in the astigmatism of the unaccommo- dated or accommodated eye exi.sts, it is not always the cylinder w^hich admits of the best distant vision that is found most suitable for near vision. Many, for instance, and especially if they are over thirty years of age, whose myopic astigmatism is corrected by a concave cylinder, prefer to use a convex one for reading, with the axis at right angles to the position in which the concave one has to be placed. The eflfect of this is, of course, to render the emmetropic, or more nearly emmetropic, meridian as myopic as the other, and not to neutralise the myopic meridian. The cause of this preference is not always, or even most frequently, connected with a habit of accom- modating for a distance at which the rays passing through the meridian of greatest curvature are focussed, as might be supposed, as generally there is a preference given both for distant and near vision for the focussing of lines in the same direction. It is probably due to its introducing a more com- fortable relation between accommodation and convergence. Most young individuals with myopic astigmatism seem to prefer, however, concave cylinders both for distant and near work. The higher degrees of astigmatism (above 4*0 D) are not common. In by far the greatest number of cases which call for correction the amount is from TO to 4-0 D. ASTIGMATISM. 481 From what has been already said, it will readily be under- stood that the amount of improvement got by cylindrical cor- rection varies very much in different cases, as this dejiends on the direction of the astigmatism, the intelligence of the indi- vidual, and the amount of possible visual acuity in each case. One effect of cylindrical correction is that the magiiitication of the retinal image is unequal in the meridians for which the correction is made. It is no doubt greatly owing to this difference of magnification in different meridians that astigmatic individuals see objects differently on proper correction than they do without correction, e.g., circles appear more or less distinctly elliptical, squares longer in one direction than another, etc. Regular astigmatism is, as has been said, mainly corneal. The total amount of astigmatism found on a complete subjective examination rarely, however, coincides with that which the measurement of curvature of the principal meridians of the cornea by means of the ophthalmometer enables one to calculate as the degree of corneal astigmatism. There are several reasons for this. One which has been long known, since Thomas Young demonstrated the existence of it in his own eye, is a certain degree of lenticular astif/7naHsm. Bonders found that the astigmatism due to the crystalline lens generally tended to counteract the corneal astigmatism. It does so when, as is the rule (see jj. 480), the vertical meridian of the cornea has the greate.st curvature. On the other hand, in corneal astigmatism, contrary to the rule, that caused by the lens leads to an additional amount. For the same reason there may be astigma- tism found subjectively where there is a complete absence of corneal astigmatism. Lenticular a.stigmatism, whether it be manifest or ma.sked by a contrary corneal astigmatism, is very rarely indeed at all high. It is due to a certain amount of obliquity of the lens, whose axis does not coincide but makes an angle with the visual axis. This angle is greatest in the horizontal plane. Tscherning, who has measured it in a number of eyes, lands that it varies as a rule from 3" to 7\ The astigmatism produced by the greater obli(|uity is not much more than ^ of a dioptre. Another circumstance which leads to the corneal astigmatism as estimated by the oiihthalmometer not corresi»onding to the subjective, or what might V^e called the clinical, degree of astigmatism, — one, too, which is apparently of greater imi>ortance than the lenticular astigmatism, — is the irregularity in the amount of curvature at different parts of the cornea. As a consequence 31 482 E11R0U8 OF llEFRACTION, ETC. of this, the degree of astigiiiatisin necessarily varies with the size of tlie pujiil. That detennined by the ophthahnometer, on the other hand, is tlie same for the same eye Avhatcver l)c the size of tlie l>upil, as the reflections from which it is deduced always take place from the same points on the cornea — from small areas not very far removed from, and on either side of, the i)oint at which the visual axis cuts tlie cornea. The astigmatism as shown by the oiihthalmometer is in fact that which Avould be }>roduced by the differences of curvature of a narrow zonular portion of the cornea (of 2 to 3 mm. in diameter) surrounding the visual axis. The measurements made by Helniholtz and others with the original ophthalmometer led to the conclusion that the surface of the cornea of a non-astigmatic eye was sutticiently approximately an ellipsoid of revolution, while that of an astigmatic eye was ellipsoidal. The calculations which led to this conclusion were based on only a few measure- ments at different parts of the cornea. As the visual axis was not, as a rule, found to coincide with the antero-posterior axis of the elliiisoid, the angle formed between these two axes received the name angle a. Measurements made by Sulzer with the more easily manipulated ophthalmometer of Javal have clearly shown that the form previously assumed for the cornea is not that which it really presents. With Javal's instrument it is easy to determine the curvature Avith great accuracy at many difierent points. The results of Sulzer's examination has been to show that in non-astigmatic eyes the central portion of the cornea is very apj^roximately spheroidal. At about 15°, or on an average 2 mm. from the point at which the cornea is cut by the visual axis, a pretty abrupt increase in its radius of curvature begins to take place. From here onwards towards the ^leriphery the cornea is more nearly ellipsoidal, the eccentricity of the ellipsoid at any point increasing on passing towards the margin. There is further to be found a degree of want of symmetry in the cornea, as there does not appear to be an equal amount of diminution of curvature for equal distances along the two principal meridians, or even for equal distances along the two halves of the same meridian. The extent to Avhich these peculiarities of shape, which characterise the great majority of corneiB, inHueuce the total degree of astigmatism, as compared with that found with the ophthalmometer, depends upon the size of the pui)il, and ujion the degree of its decentration. Sulzer found the centre of the pupil situated, as a rule, from 2° to 9°, or on the average 5°, to the temporal side of the visual axis. The usual effect of the HEADACHES DUE TO ASTIGMATISM. 483 summation of the ditfereut tlegrces of astigmatism at different parts of the pupillary area of the cornea was found to be as follows : — (1) That in eyes which do not show any astigmatism with the ophthalmometer, there is found subjectively a slight degree of astigmatism, contrary to the rule ; (2) that in eyes showing with the ophthalmometer a low or moderate amount of ordinary astigmatism, the subjective astigmatism is found to be less, altogether absent, or contrary to the rule, according to the ophthalmometric amount, the degree of corneal asymmetry, the size of the pu[)il, and the extent of its decentration ; (3) that in eyes showing with the ophthalmometer an astigmatism contrary to the rule, there is found subjectively a higher amount of the same variety of astigmatism, owing to the influence of the temporal portions of the cornea for which the astigmatism is more pronounced ; and (4) that in eyes showing with the ophthalmometer a high degree of ordinary astigmatism, the subjective astigmatism is often found to be even higher. Very soon after the ophthalmometer came to be generally used as a clinical instrument, the difference between the degree of total astigmatism as determined subjectively and that found with the ophthalmometer attracted attention. The explanation first given by Javal, and one which seems, notwithstanding its a ji^'iori improbability, to have received an astonishing amount of support, was that by an irregular or unequal contraction of the ciliary muscle, the lens could be rendered to a certain extent astigmatic, so as in some degree to overcome the corneal astig- matism. Such irregular ciliary contraction is now known not to exist. It has been shown that the differences in cpiestion are mainly due to the shape of the cornea itself. The importance of a consideration of this subject at all, apart from its scientific interest, lies in the practical clinical deductions which have been made on the assumption of the correctness of Javal's explanation. It has been held, for instance, that the supposed irregular contractions of the ciliary nuiscle, induced in the effort to counteract a corneal astigmatism, are etfected Avitli an amount of strain which gives rise to headache and other nervous disturbances, to a tendency to increase of myopia, and even to corneal inflammations. Headaches due to astigmatism. — ^The slighter degrees of astigmatism are not unfrequently the indirect cause of headaches. The same irritation which gives rise to headaches from this cause may even, in particularly nervous subjects, cause still more marked neurotic symptoms. In probably all cases the headaches are due to the siinnnation 184 EUllOllS OF REFRACTION, lilTC. of irritation caused by lid-pressuro on the cornea. Tlie effect of this pressure is to remove or alter tlic amount of an existing astigmatism. It is easy to demonstrate, ])oth by subjective tests and by measurement with tlie ophtlialmometer, that sliglit pressure with the finger is cajjable of producing very marked changes in corneal curvature. Indeed some astigmatic in- dividuals frcc|uently correct their defect by })ressure ajtplied in this way. In the slighter degrees of astigmatism a sinular correcting pressure is unconsciously made by the lids. The individual doing so may or may not be conscious of the hal)it of frowning. It is mostly in the cases of astigmatism "contrary to the rule," i.e., cases in which the horizontal, or a]>proximately horizontal, meridian is the most highly curved that this uncon- scious lid-pressure correction can be effectively applied. As, too, only the slighter degrees of astigmatism can be modified in this manner, irritation leading, on summation, to headache is practically limited to such cases. At the same time there is frei^uently also some degree of conjunctival congestion, produced by the j)ressure. In all cases in which there are headaches which, from their association with the use of the eyes, are suggestive of having an ocular causation, this astigmatism should be looked for. This is particularly important where there is no hypermetropia to account for the symptoms. It will then often be found that the use of cylinders of 0'5 or 1"0 for reading, with the axes placed vertically if concave or horizontally if convex, will per- manently relieve the headaches and remove the symptoms of the conjunctival congestion. For the same reason, care must always be taken, in giving cylindrical correction for a degree of astigmatism, according to rule, sufficient to cause defective vision, that the correction is not overdone. While vision may be greatly improved by these cylinders, the introduction of even a slight degree of astigmatism in the opposite direction may lead to discomfort, and to the glasses being discarded. Irregular astigmatism. — A want of symmetry in the curvature of the lenticular or corneal surfaces gives rise to irregular astig- matism. This condition may be either congenital or acquired. The congenital is mostly dependent ujion abiiormal conditions of the crystalline lens ; the acquired form, on the other hand, is mainly the result of alterations in the corneal curvature, caused by cicatricial contractions following intianunations. The lenticular form, whether congenital or acquired, is often more pronounced for near vision, the defects of the lens IRREGULAR ASTIGMATISM. 485 being more marked when it has undergone an accommodative change. Irregular astigmatism does not admit of optical correction, though many eyes which exhibit this defect are greatly improved by spherical or cylindrical lenses, owing to the coexistence of the more regular anomalies of refraction. Sometimes a stenopaic aperture opposite some particular portion of the cornea eflects an improvement. The diagnosis is readily made by the ophthalmoscope, by the indirect method of examination. On withdrawing or approach- ing the auxiliary lens to the eye, the papilla is observed to assume various irregular shapes, giving rise to an appearance quite characteristic of this condition. If the irregular astig- matism be corneal, it is beautifully seen by the use of Placido's disc, with which instrument it is easy at the same time to discover the portion of the cornea, if any such portion exists, in which the curvature is least abnormal. A number of inconveniences are experienced by the wearer of spectacles, some of which ^la. 190. — Distortion depend on the altered physical, others on of Placido's rings on the altered physiological, conditions which ToSfa'th S^ulnr are brought about. Some of the aj^parent astigmatism, distortions complained of cannot be referred to any physical cause. The altered relation between accom- modation and convergent movements, already referred to, often introduces a difficulty when correcting glasses are first used late in adult life. Most of the difficulties experienced on first wearing glasses disappear, however, if the glasses have been properly chosen, and are suitably placed in front of the eyes. Owing to the prismatic action of the glasses, the field of vision taken in by a concave glass is largei', and at the same time more compressed ; that taken in by a convex lens, on the other hand, is smaller and more dispersed than that seen through a simple ajjerture of the same size as the glasses. When the same glasses are worn both for a distance and near, they should be centred for distant vision. Reading glasses should be centred for the distance at which they are used, and should be at the same time slightly tilted in their frames, .so that instead of being parallel with the face, they come rather nearer it l:)elow than above. A simple method of mea.suring the interpupillary distance is 48G EIIUORS OF REFRACTION, ETC. by means of Snellen's si^ectacle frame (Fig. 191), which consists of a pair of jilane glasses in an ordinary frame, with a vertical Fig. 191. — (Slightly reduced iu size) line scratched in the centre of one gla.ss, and a number of lines 1 millimetre apart scratched on the other. By putting these Fig. 192. — Position of prisms causing adduction and diminishing the necessity foi' aluhictiou. on the patient's nose, and causing him to look at a distance, and in such a direction that with one's own left eye the line on ACTION OF PRISMS. 487 the glass opposite his right passes through the centre of liis [nipil, and then observing which line on the other glass is seen by the right eye (on closing the left) to be o[»i>osite the centre of his other pupil, it is easy to measure tpiickly the intei'-pupillary distance with sufhcient accuracy for all })ractical purposes. Sometimes prisms are used in the form of spectacles, alone, or combined with spherical lenses, in order to ease the movements of convergence or divergence, or, where these movements are Fig. 193. — Position of prisms causing aliductiou and diiiiinisliing tlie necessity for adduction. enfeebled, to stimulate them. Their use is limited, and they are rarely of practical value, on account of their weight and the chromatic aberration and astigmatism which they })roduce when at all strong. The action of transparent prisms of greater density than the surrounding medium, and therefore of }trisms of glass surrounded by air, is to refract the rays of light which pass through them in such a manner that their direction after refraction is more towards the base of the prism than that in which they are 488 P^UROKS OF KEFK ACTION, ETC. incident. Prisms with the bases outwards before one or both eyes, therefore, cause ol)jects to appear nearer and smaller, owing to a greater degree of convergence being necessary to bring the rays from them on to both macuUe, than when the prisms are absent. Prisms with their bases inwards, on the other hand, cause objects to appear more distant and larger than they are, owing to the convergence required for their binocular fixation being lessened. Prisms in the former position therefore lessen the strain on divergent movements, and at the same time tend to induce greater convergent movements. Exactly the opposite is the case when they are placed in the latter })osition. This will be readily understood by a reference to Figs. 192 and 193, the con- tinuous line being the direction of the axial rays from the object, the dotted ones the direction in which they a]»})ear to come. Prisms of 4° in front of each eye are about as strong as can Fig. 194. — To aliow the inauiier in which orthoscopic lenses are got. conveniently be worn in most cases. Under special conditions considerably stronger ones are tolerated. The angular deviations produced by ordinary glass prisms is equal to half the angle of the prism ; therefore, with 4° prisms in front of each eye, the deviation amounts to 4° in all. A decentriug of each convex lens to the extent of one-half of the interocular distance gives the same assistance to convergence as it does to accommodation. This effect is i)roduced by ortho- scoi)ic lenses, or lenses which are portions of a large lens at distances to either sitle of its axis equal to half the interocular distance (Fig. 194). Anomalies of Accommodation. Reference has already been made to what may be called the })assive defects of accommodation, namely, those which depend PARALYSIS OF ACCOMMODATIOX. 489 upon the absence of a suitable alteration in the curvature of the crystalline lens in response to a definite contractile change in the ciliary muscle. The chief defect of this nature— presbyopia — -is physiological, inasmuch as it is a necessary consef^uence of the manner in which the growth of the lens takes place under normal conditions. In the various dislocations and sub-luxations of the lens we have, on the other hand, the chief causes of pathological ^mssive defects of accommodation. ;More active accommodative defects arise from an interference with the function of the ciliary muscle. That muscle may be incapable of contracting at all, or its contractile power may be weakened. Paralysis of accommodation. — Complete paralysis is almost invariably the result of some lesion of the third nerve. Paresis, on the other hand, may be either a muscular or an innervation weakness. Associated with complete paralysis we usually find, at all events, paralytic dilatation of the pupil; not infrequently also paralysis of the oculo-motor muscles supplied by the third nerve. These different paralyses are not so often found coexisting with partial paralysis of accommodation. Sometimes, however, there is at the same time a degree of paresis, or even complete paralysis of convergent movement, a movement which is usually associated ■with active changes of accommodation. Roughly speaking, the affection which leads to paralysis of accommodation may be either central or peripheral. For instance, the paralysis may be one of the symptoms of all lesions of the brain — injuries, inflammations, tumours — which involve either the trunk or nucleus of the third nerve. Similar affections of the orbit, too, may, by involving some or all of the branches of the third, cause interference with the power of the ciliary muscle. A peripheral neuritis, on the one hand, and disease limited to the accommodation centre, on the other, may be the cause of paresis of accommodation alone. Two of the most interesting clinical forms of isolated accom- modation paralysis are the cases following concussion of the brain and diphtheria. I have seen several cases of more or less jtronounced paresis of accommodation after railway accidents. The existence of such a paresis may indeed jn-ove to be the most important evidence of shock sustained. In the case of a woman who was for some months a patient in the Royal Infirmary, almost complete paralysis of accommodation was apparently the only permanent injury resulting from a fall from an express train travelling at the rate of forty-five miles an hour. 490 EIir.ORS OF REFRACTION, ETC. Paralysis of accommodation following diplitlieria is of pretty common occurrence. It is probably always bilateral, and rarely complete. The paralysis first makes its appearance some weeks after recovery from the diphtheria, at a time, too, when the patient has to a great extent recovered, and seems in other respects in good health. Occasionally it may be as.sociated with other pareses, such as mydriasis, paresis of convergence, paresis of the sixth. iSometimes a concomitant convergent strabismus may exist along with the paresis of accommodation. Of other l)aralyses, that of the soft palate is much the most frequent. The most notable feature in connection with the etiology of diphtheritic paresis of accommodation is that no evident rela- tion exists between it and the severity of the preceding throat affection. Often, indeed, that has been so slight as to have been overlooked. It has even been asserted by some writers that the diphtheritic poison may lead to j)aralysis without having given rise to any local inflammation. The ^jro^'/iosi's in diphtheritic paresis of accommodation is more favourable than in paresis of accommodation from almost any other cause. It does not, as a rule, last longer than from four to six weeks. The treatment should consist in giving tonics, especially iron and quinine. Miotics (eserine or pilocarpine), which are usually recommended, are of very doubtful value ; possibly, indeed, they may sometimes do harm. I have often prescribed the tempox'ary use of convex glasses of sufficient strength to enable the patient to read in moderation without any strain of accommodation. Various views have been held as to the cause of diphtheritic paralysis. Probably the pathology of the rarer and less symmetrical paralyses may be different from the more common paralysis of the palate and ciliary muscles. There can be little doubt that post-diphtheritic accommodation paresis, at all events, is due to some toxic action on the brain. The bilateral character of the pareses, its transitory nature, the occasional complication with paresis of other associated movements, are all suggestive of such a cause. Certain products of decomposition, particularly of fish, also cause paralysis of accommodation when absorbed from the alimentary canal. The only apparent difference between the paralysis arising in this way and the post-diphtheritic variety is that the former is more transitory. This probably is simply because the poison is more rapidly eliminated from the body. How the poison producing paralysis after diphtheria is formed, or how it is eventually eliminated, is not known. PARALYSI8 OF ACCOMMODATION. 491 Of the toxic effects coining under the notice of the oi)htliahnic surgeon, that which pei'haps most closely resembles diphtheritic paralysis of accommodation is the central amblyopia i)roduced by tobacco (see p. 416). Both with respect to their bilateral character and their slow disaj^pearance, there is a considerable resemblance between these two affections. In both cases it is not certain how the poison acts, whether directly on the centres or indirectly through some localised vasomotor change. In the case of tobacco there is known to be some direct toxic effect on certain nerve cells. Weakening of accommodation owing to exhaustion of the ciliary muscle is a very frequent result of any severe debilitating illness. Many months may then elapse before the muscle regains its full power, or, at all events, is cajmble of prolonged efforts of contraction. The same symptom characterises most forms of neurasthenia. The ciliary muscle may be overstrained, too, when prolonged efforts of accommodation are made under adverse conditions, such as the presence of corneal opacities, astigmatism, etc. The amplitude of accommodation may thus be temporarily diminished. Diminution of accommodation may also be brought about reflexly, and in this way may arise from facial neuralgia, tooth- ache, etc. Whether partial or complete, the greatest inconvenience from paralysis of accommodation is felt by a hypermetrope, and the least by a myope. In hypermetropia the absence of accommoda- tion causes an indistinctness of distant as well as of near vision. In emmetropia only near vision is interfered with, while in myopia of four or more dioptres the disturbance is so slight that it may remain unnoticed. It is not difficult to diagnose the presence of complete paralysis of accommodation even in the case of myopia, especially if the myopia admits of good correction. In addition to innervation and muscular weaknesses, an inter- ference with acconunodation may result from inflammatory or atrophic conditions of the ciliary muscle. The most freipient example of this form of paresis is met with in glaucoma, of which affection it is not unfrequently an early symptom. Spasm of accommodation. — True, persistent spasm of accom- modation is either of very rare occurrence or has no real exist- ence at all. I have certainly never met with a case. I have not unfrequently, however, seen cases of so-called spasm of accommodation in which an attempt at .seeing distinctly is apt to produce an excessive and unsuitable degree of acconnnoda- 492 EPvnOTlS OF r^EFP.ACTTOX, ETC. ti(in. Siicli iiulividuals, if einmetiopic, are found only to see distinctly at a distance with concave glasses, and may thus be mistaken for myopes. If examined with the ophthalmoscope, the true state of refraction is at once evident. This shows that the spasm is only induced when attention is directed to external objects. A similar contraction of the ciliary muscle takes place, in fact, to that which in a young hyiiermetrope leads to some of the hypermetroiiia being latent. The difference between the estimation of the refraction got respectively by a sulijective examination and direct oi)hthalmoscopic examination affords the only means of diagnosing the condition with certainty, unless recourse be had to paralysing the ciliary muscle by the use of atropine. Not uufrequently the temporary spasm may be susjjected before an ophthalmoscopic examination is niade, owning to the manner in which the ])atient reads the distant test types. At the moment, if asked to read the smaller letters, he is quite unable to do so, but if he begins the next moment with the larger letters and finally passes through the series, he may momentarily exhibit a far greater visual acuity than he has, as a rule, without concave glasses. Those most liable to suffer in this way are young women whose occupation necessitates constant accommodation for near objects. CHAPTER XVIII. AFFECTIONS OF THE OCULO-MOTOll MUSCLES. Physiological and Introductory. The eye i« freely moved in all directions round a practically fixed point, its centre of rotation, by the action of one or more of the six external muscles. The centre of rotation lies about 1 nnn. behind the centre of the eye. The six muscles constitute three antagonistic pairs — (1) The lateral recti (externus and internus), which rotate the eye round a vertical axis ; (2) the superior and inferior recti, which rotate the eye round an axis which meets the middle line in front of the eyes at an angle of 63° ; (3) the two oblique muscles, which rotate the eye round an axis which meets the middle line behind the eye at an angle of 39° (see Fig. 195). The direction of action of the first pair is lateral ; that of the second and third is represented by the figure. If each muscle were to contract alone, the displacement of the cornea which it would produce would be as follows (see Fig. 196). The externus would displace the cornea outwards, without any torsion, round the antero-posterior axis ; the internus would displace the cornea inwards, also without any torsion. The superior rectus would displace the cornea upwards and slightly inwards, and at the same time twist the upper part towards the nose (medial torsion). The inferior rectus would displace the cornea downwards and slightly inwards, and twist the up})er part away from the nose (lateral torsion). The superior oblique would displace the cornea downwards and slightly outwards, and produce at the same time medial torsio)>. The inferior oblicpie would displace the cornea u])wards and slightly outwards, and produce lateral torsion. All the recti muscles tend to pull the eye back into the orl)it and are therefore retractors. The oblique muscles counteract this by tending to pull the eye forwards. They are jivotractor muscles. 494 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. Purely lateral movements are effected by the external and in- ternal recti alone. Purely vertical movements are effected by the combined action of a straight aiul obli(jue elevator or de})ressor. Movements in intermediate directions are effected by the cond)ined action of a lateral and two elevating or depressing muscles. Purely vertical or i)urely lateral movements, starting from a position in which the visual axis is directed straight forwards in the horizontal plane (a position which may be called the initial position), bring the eye into what are called primary 2>ositions. Movements of the eyes into primary [)ositions take place without any torsion. In the case of purely lateral movements Fig. 195. the reason of this is obvious ; in the purely vertical, it is because the torsional movements of the two elevators or depressors counteract each other. Movements into positions intermediate between i)urely lateral and purely vertical, or into what are called secondary 2)ositions, are accompanied by torsion, the direc- tion and extent of which depends on the direction and extent of the lateral and vertical displacement from the initial position. When the eye is abducted, or turned away from the nose, the torsional effect of the oblique muscles preponderates ; when it is adducted, i.e., turned towards the nose, the torsional effect of the recti preponderates. It follows from this — what is found experi- ASSOCIATED MOVEMENTS. 495 Ki-lit. Sup. ol)l. Inf. obi. Slip. reet. mentally to be the case — that when both eyes arc turned in the same direction into any secondary position, i.e. upwards or downwards, to the right or left, the torsion is in the same direction in both eyes, — as one is ac/fZucted, the other ab- ducted, — so that in the one the torsion is lateral and in the other medial. A ssociaUd mo veme n ts. — The eyes move in association later- ally or vertically, or in direc- tions intermediate to these two. These associated move- ments are so intimate that they may be voluntarily brought about without the aid of any object of fixation. We can at will look to the right or left, or up or down ; and we can move the eyes together in these directions even when the eyelids are closed. According to some, this as- sociation is inborn, and the result of stimulation ])assing to the muscles from delinite anatomical centres in the brain. According to others, it is acquired as the result of the habit of binocular fixation. Whatever the cause may be, the association is so intimate that it continues to exist for an indefinite time after any regulation, by the desii'e for binocular vision, has been ren- dered impossible from the loss of sight in one eye. In certain conditions we may find a spasmodic rotation of the eyes in some particular direction, or a more or less complete paresis of associated Fig. 196.— Diagram showing movement of corneii produced by each muscle separately. 490 AFFECTIONS OF THl': OCUTLO->r()TOTI :srUSCLES. iiioveinciits. These, however, are tlic result of cerebral disorder, and not of any defect of binocular vision. In nystagmus, again, we see associated contractions existing which do not sul)serve the purposes of l)inocular fixation. ]'erlia[)s the most noticeal)le tiling in associated lateral move- ments — and it is mainly with lateral movements that we have to deal in connection with strabismus — is their accuracy. The two associated muscles evidently receive equal imjmlses to contrac- tion. We have evidence of the same equality of imjnilse con- veyed to two separate muscles in the case of the ciliary muscles, which are incapable of unequal contraction. When, from jiaralysis or any mechanical cause, the eye cannot be rotated in some particular direction, in accordance with the impulse which the muscle receives in order to etiect such rotation, the amount of impulse conveyed is nevertheless shown by the extent to which the associated muscle contracts, so as to move the other eye in the same direction. Under these circumstances, then, the greater the impulse the greater is the deviation of the faulty eye from the direction of fixation. Any defect in the muscular response to a nerve im})ulse, uidess it be of exactly the same degree in two muscles which usually act in association, must interfere with the accuracy of the associations, and therefore lead to the relative directions of the lines of vision of the two eyes ditt'ering for different direc- tions of fixation. The greatest possible movement of the eyes takes place down- wards, and the least upwards. Convergence. — Besides associated movements in similar direc- tions, we have to consider movements of convergence in which the two eyes are associated in movements which take place in opposite directions. There is good I'eason, too, for believing that the impulse leading to convergence is equally distributed over the two internal recti. Convergent movements are not, liowever, so readily induced, independently of any object of fixation, as are similarly directed movements. It is not easy for anyone to converge, on being told to do so, without having any object to converge on, although with practice it can be done. Convergent movements, further, may become greatly enfeel)led, or altogether cease, simply as the result of more or less disuse, and without there being any abnormal condition of the central nervous system to account for this. It is important to remember, too, that in all cases in which impulses to convergence are absent, a manifest divergence of the ocular axes is the result. There is only one exception, namely, where there is produced, as the CONVERGENCE. 49"; result of some cerebral disorder, e.g. after diphtheria, more or less complete temporary paresis of convergence. But here, no doubt, the tonic element of convergence innervation remains unimpaired. Fig. 197. — The angles C represent the deviation which each eye teuds to undergo from being directed straight forwards (parallel axes) to being directed towards a point P' nnder an impulse to con- vergence. The angles A represent the deviations of tlie two eyes laterally from a convergence on P^ to convergence on 1' under an impulse to associated lateral movement. These two impulses being similarly directed in the right eye, supplement each other ; but being oppositely directed in the left eye, neutralise each other, as indicated in each case l)y the arrows. Convergence is also associated with accommodation, ?'.e., when the two internal recti act simultaneously there is more or less tendency to an associated action of both ciliary muscles. .^2 4i)8 AFFECTIONS OF THE OCULO-MOTOll MUSCLES. Comhined moveinenfs, axxociated and convergent. — The two associated movements, similarly directed and opjiosed, may be combined. We are able, for instance, to maintain the fixation of a near object, moved from side to side, with no greater difh- culty than we do for one i\t a distance, when the two eye axes are parallel. Take, for instance, the case of a near object placed directly in front of one eye. What impulses lead to its fixa- tion by the two eyesi They are two. First, an impulse to convergence equally distributed over the two interni, and which would produce a convergence towards a point at the same distance as that actually fixed, and placed midway between the eyes ; and, secondly, an impulse to associated lateral movements, equally distributed between the internus of the one side and the externus of the other side. This is represented in Fig. 197. Accommodation and converg- ence. — Whilst there is no doubt that an association exists be- tween accommodation and con- vergence, it is by no means easy to determine what is its exact nature. And this not only with reference to the starting- point in the brain of the simul- taneous impulses to convergence and accommodation, but more particularly to the intimacy of the association. As in the case 198. -To sliow cliagranniiaticaUy ^f ^^le other associated imimlses, the measurement of convergence m ' ... ' metre-angles. that conveyed to the two ciliary muscles and those which control the simultaneous similarly directed and opposite movements of the two eyes, it might seem reasonable to infer that the impulses to convergence and accommodation are coextensive. That is to say, that for every unit of impulse towards accommodative change there should be a corresponding unit of impulse to convergence. ACCOMMODATION AND CONVERGENCE. 4'.)'.) The unit of accommodation is the dioptre. Thus M'licii the eye, from being accommodated for a distant point, becomes accom- modated for one at a distance from it of 1 metre (39^, or roughly, 40 English inches), there has been a change ettected to the extent of 1 diopti-e. The .same change again takes place when, from accommodation for the distance of 1 metre, or ^ a metre, or ^ of a metre, accommodation is altered to that for h metre, ^ metre, and ^ metre respectively. In the same way the corresponding unit of convergence is the metre-angle, or the angular deviation of both eyes towards the middle line, when, from fixing a distant object with their axes parallel, the -eyes converge upon one placed at a distance of 1 metre from each ; or the deviation which occurs when, starting from the fixation of an object at 1 metre, or ^ metre's distance, \8 7 6 5 13211^1 2345678P ' Fio 19ft. -Showing the manner in which deviations are measiired on a tangent scale by means of the Maddox rod. the convergence is increased in order to fix an object at ^ metre or ^ metre respectively. This is shown diagrammatically in Fig.' 198. The manner in which the relation between convergence and accommodation may be tested practically is by causing the patient to fix with one eye an object at about 10 in. or | metre from the eye, while the observer's hand is held in front of the other eye ; on then removing the hand after ten or twenty seconds, the previously occluded eye either makes a movement inwards or outwards, or remains in the position it assumed behind the occluding hand. If after removing the hand a movement of the eye takes place inwards, it shows that it was diverging, if outwards, converging, relatively to the direction it should have. It is important, in making this test, to make sure that the uncovered eye is accurately accommodated for the 500 AFFECTIONS OF THE OCULO-MOTOR MU8CLES. object fixed. To discover tlic ]tosition of innervation equilibrium, indei)endent of any accommodative impulse, all that is required, in the case of emnietroi)ia and myopia, is to examine in the same way, only that, instead of fixing a near object, the uncovered eye is caused to fix a distant one. When there is hy})ermetropia, an approach to the actual condition may be made, greater or less according to circumstances, by correcting the hypermetropia before making the test ; but even when the total hypermetrojiia is corrected after the use of atropine, there may still remain a certain degree of convergence, brought into play by an imjnihe to accommodation. It is sometimes desirable, however, to make moi'e precise and more definitely quantitative measurements of latent deviations ; and to do this, on distant fixation, a very simple and easily Fig. 200.— Maddox rod. applied test is that with the Maddox glass rod and tangent scale. The patient stands facing a large scale, graduated in tenths of a metre angle for the distance (5 or 6 metres) at which the test is made. At the centre of the scale is a candle flame. This is fixed by the one eye. In front of the other a cylindrical rod, of 5 to 6 mm. in diameter, of clear red glass is held hori- zontally. The effect of this is to present to that eye a long vertical red-line image of the candle flame. If there be no latent lateral deviation of the eyes, this linear image appears to pass through the centre of the flame. The existence of a lateral deviation, on the other hand, causes the line of light to appear to cut the scale at some distance — which can be easily read on the scale — to one side or other of the flame. Fig. 200, a, shows the rod fixed opposite a slit in a small metal screen, which pre- MEASUUE^EENT OF DEVIATIONS. 501 vents any object being seen by the eye in front of wliirli it is held except the elongated image of the flame. Fig. 200, b, shows another arrangement, consisting of a number of rods, by which the same effect is o])taiued without any difficulty in bring- ing the cylinder opposite the pupil. Fig. 199 shows the manner in which the line of light is projected on the tangent scale. For the accurate measurement of deviations at nearer distances of fixation the method introduced by Maddox, with a tangent scale and a prism of 10°, placed base upwards in front of the non-fixing eye, may be most conveniently adopted. Fig. 201 shows a portion of a scale graduated in metre angles for a fixation distance of |- of a metre, — a distance corresponding suffi- ciently to the ordinary reading distance ; when the scale is held in front of the patient at the proper distance, and the central or zero point fixed, the lower ari'ow, i.e., the false image caused by the prism, points to the number on the scale which indicates the Fig. 201. latent deviation for that distance of fixation and to cither side of zero, according as the deviation is one of convergence or of divergence. Each scale should have attached to it a string of such a length that when the free end is held by the finger of the individual examined against his own temple, the distance at which the scale should be used is obtained by keeping it stretched. A line of small print is introduced below the scale, with the object of securing accurate accommodation, a matter of the utmost importance in making measurements from which any deductions as to existing relations between acconnnodation and convergence are to be drawn. For measuring vertical deviations on distant fixation the glass rod and a vertical scale graduated in degrees, with a small fiame at the zero point, is most convenient. The metre-angle .scale has, of course, on^y a raison d'etre in connection with lateral deviations. 502 AFFEC'TTOX.S OF TITF ()CULO-:\rOTOU ^lUSCLES. The ideal connection between accommodation and convergence is such, that for every dioptre of accommodation there shall be a metre-angle of convergence. This is actually what takes place on binocular fixation in the case of emmetropic eyes. Where an object, say at j metre (or about 10 in.), is fixed so as to be seen with the greatest i)ossible distinctness, there is required an accommodation of 4 dioptres, and at the same time there is a convergence of 4 metre-angles. In order, however, that there should be an evidence of association between the accommodative effort and the convergent one, this })osition of convergence should also be maintained in the absence of binocular vision, or when the one eye is occluded from fixation. Under such conditions, then, it is found that the 4 metre-angles of convergence may or may not be retained ; that is to say, that the occluded eye may or may not remain in the same i)osition as it occupied when both eyes were allowed to maintain fixation. More often it does not ; and when it deviates outwards (or, in other words, when there is a relative latent divergence), we might still suppose that there was an impulse to convergence coextensive with, and associated with, the impulse to accommodation, but that the actual defect in the amount of convergence seen w-as due to the starting-point for convergence being a state not of parallelism of the axes but of divergence. But let us see what takes place in other states of refraction. In the case of myopia of 4 dioptres, fixation of an object at I metre from the eyes takes place without any accommodation, whilst the interests of binocular vision necessitate 4 metre-angles of convergence (starting from parallelism). On occlusion of one eye, binocular vision being abolished, and there being no accom- modative impulse to carry along with it an impulse to converg- ence, one might expect to find an outward deviation to the extent of at least 4 metre-angles. In point of fact, whilst one does find more fretpient and more marked relative latent diverg- cncG in myopes than in emmetropes, it is rare to find, in moderate degrees of myopia, the divergence anything approach- ing in amount that which would indicate such an ideal associa- tion between accommodative and convergent impulses as we have assumed might be expected to exist. In cases of myopia, then, with the imi)ulse to convergence which is excited , by the desire for binocular vision, as well as that which would be associ- ated with accommodation, both cut off, there must be some other factor present which leads to the retention of all or most of the convergence. But let us turn to the case of hyjjer- metropia. LATENT POSITIONS. 503 A hypermetrope of i dioptres must, in order to see distinctly at a distance, accommodate to the extent of 4 dioptres. To see distinctly at | metre he must accommodate to the extent of 4 dioptres more. Therefore, on binocular fixation of a point at \ metre distance, while he accommodates 8 dioi)tres, he converges only 4 metre-angles. But what of the latent position 1 If the assumed ideal relation between accommodative and convergent impulses were to show itself, we should expect to find, on occlud- ing the one eye, that the convergence increased to 8 metre- angles. In other words, there should be a large latent relative convergence. Here again, however, the actual experiment gives little or no evidence of this assumed association. No doubt a relative latent convergence is more frequently met with in hyper- metro pes than in either emmetropes or myopes, but in amount it almost invariably falls far short of that which would indicate so intimate an association between the two impulses under consideration. There must, then, either be no such intimate association, or it is masked by some other factor which tends to maintain much the same degree of convergence as that which subserves the purpose of binocular fixation when both eyes are free. It is of course jDOSsible, as has already been said, that convergent move- ment may start from a position of absolute divergence of the ocular axes, not from one of parallelism. Yet as we have seen how little the relative latent position on near fixation in emme- tropia and myopia is in accordance with this supposition, it is more than probable that it is not this which causes the degree of convergence to remain so approximately equal to the re- quired amount for binocular fixation, whatever be the .state of refraction. Latent 2)ositions. — Another point which has to be investigated is the latent position of the eyes for distant fixation. It is often assumed that this latent position — that is, the position taken up in the temporary absence of binocular fixation — is the position of rest of the eyes. There is very considerable diversity of opinion, however, as to what should be understood by this position of rest. By many, indeed by most, who have investi- gated this subject, the latent position for distance is looked upon as the so-called anatomical position of rest. This view is certainly incorrect. The ocular muscles, like other muscles in the body, are in a continual state of tonic contraction : they are constantly innervated. The examination referred to can then only reveal the relative position which the eyes take up, inde- pendently of binocular fixation, when the muscles are in a com- 504 AFI-KCTH)XS OF TlIK OCULOMOTOR MU8CLE8. piiralivi'ly passive state — in a state wliioli tliey assume when, altliougli tliey are frequently moved to convergence and similarly directed associations, their muscles arc only left with that degree of tonic contraction which the repeated resiionse to these impulses entails. It can in fact only be a position oi functional rest. An examination of a great number of cases of different states of refraction, as to the positions of functional rest of the eyes, shows that : 1. In emmetroi)ia, deviations from parallelism to any consider- S "2lVlA, Im.a. 2ma. 3ma 4m.a. Im. •5m. •3m ■25m \ \ - \ \ \ \ N \ S \ N \ \ \ \ \ Fig. 202. able extent are, comparatively speaking, infrequent. Although it is rare to find absolute parallelism, deviations greater than i metre-angle, either in the direction of divergence or of converg- ence, are not frequent. Practical })arallelism is therefore the rule. In these deviations from i)arallelism it is more common to find divergence than convergence. Higher degrees of latent lateral deviation are met with in a small proportion of cases, and more frequently divergence than convergence. 2. In hy|»crmetropia, approximate i)arallelism is a less common latent position than in ennnetropia. Latent convergence is more LATENT POSITIONS. iOO common in this state of refraction than latent divergence. Tlie anionnt, too, of latent convergence in metre-angles is seldom greater than that of the hy})ermetroina in dioptres. 3. In myopia, approximate parallelism is also less frequent than in emmetropia. Both divei'gence and convergence are about equally frequent with this condition of refraction, but the degrees of divergence are more often higher than the degrees of converg- ence. The amount of divergence, too, is only occasionally, and mainly in the very low degrees of myopia, as great (or greater) in metre-angles as the myopia in dioptres. ,2ivtA I MA 2|VIA 3 MA 4ha. IM. •Sm. •3m •23m N \ \ V \ \ \ \ N \ \ Fig. 203. Accurate measurements of the latent position for distance show, then, that although there is a distinct evidence of an association of some kind between accommodation and converg- ence, there is no evidence of the a.ssociation being as intimate as it might be sup])osed to be. It does not follow, however, that the actual imindses are not associated in a more ideal manner. But if they are, they are for some reason or other prevented from becoming manifested in the actual relations which are found to exist between the extent to which the eyes are accommodated 50G AFFECTIONS OF THE OCULO-MOTOll MU8CLE8. and converged in the absence, tenii)orarily, of wliat is of course the sui)reme controlling influence, namely, the desire for bin- ocular vision, or fusw)i as it is more shortly termed. We may, besides measuring the latent position for near (say at I metre) and for distance, also determine it for intermediate distances. The relation existing throughout may be exhibited in a grai»hic manner, as shown in the accompanying figures. In these figures the scpiares are formed ])y vertical lines, which re- present the same distances of fixation from 5 metres to ^ metre. •2WAw Ima 2M.A. 3MA. 4MA. •5m. • 3m •25m ■-N \ \ \ N \ \ ^ \ \ \ \ \ \ \ \ \ S Fic!. 204. crossed by horizontal lines, representing the same degrees of con- vergence, from 0'2 to 4 metre-angles. The diagonal line is, therefore, in the case of emmetropia, the line of equal accom- modation and convergence. In Fig. 202 is rei>resented the case (a fairly typical one in emmetropia) in which there occurs a gradual lagging of converg- ence behind accommodation, as nearer and nearer objects are successively fixed. With no, or ])ractically no, accommodation, there is found to be a mere trace of latent divergence ; with 2 dioptres of accommodation the divergence has increased to ^ a LATENT DIVERGENCE. 507 metre-angle, whilst 4 dioptres of accommodation, induced by tixation at | metre, has advanced it to 1 metre-angle. The amount of lagging found through the same range in different cases is different. Not infrequently it is barely as much as 1 metre-angle. Sometimes there is less latent diverg- ence on fixation of ^ metre than for ^ metre. Fig. 203 shows this. Sometimes, again, there is considerably more retardation in the convergent movement when unaided by fusion. Such a case is represented by Fig. 204. It is rare that with this relationship there is any discomfort felt in reading. 5m ■3m. •»M. \ \ \ \ 2ma 1m« \ 4ma N \ \ \ \ \ \ \ Fig. 205. A similar high degree of relative latent divergence is found, as a rule, in myopes who are in the habit of reading without correcting glasses. Even when the latent position for distance is a convergent one, we may see the same lagging of convergence behind accom- modation. In Fig. 205 is shown a case in which the latent con- vergence soon passes, for nearer fixation, to a divergence ; while Fig. 206 shows a diminution in the extent of convergence as nearer points are fixed. When the latent position for distance is a convergent one, 508 AFFECTIONS OF THE OCULO-MOTOll MUSCLES. the rule is that there is a greater tendency for the convergence to keei) i)ace with the accommodation, and tlie more so tlie more marked tlie convergence for distance is. In hypermetroiiia of any considerable degree, for instance, there is little tendency for the latent convergence to diminish as the fixation point is ap- ]»roached to the eye. Fig. 207 shows the retention of convergence in an emmetrope. Fig. 208 the increase of latent convergence for nearer distances in a hypermetrope. In order to understand better the causes for the a})parent difference existing in different cases, in the manner in which •2m.^ Im.a. •5 m. •3 m. •25 m. 3 MA 4MA. N \ N S \ \ \ \ \ \ \ \ \ \ \ \ \ \ S \ \ s s ^^1 Fig. 206. accommodation and convergence are associated, we may intro- duce artificial conditions of accommodation. The investigation of tlie extent to which a dissociation of accommodation and con- vergence can be tolerated in the interest of fusion was made long ago by Bonders. He determined the extent to which the eyes could overcome by accommodation the effect of concave glasses, while continuing to retain the same degree of convergence, and therefore binocular fixation. Nagel, again, made a series of ex- ])eriments to test the extent to which adducting prisms could be overcome by convergence without altering the degree of accom- modation. RETENTION OF CONVERGENCE. 509 With the object of finding out the change which takes phice u\ convergence in increasing accommodation when liinocular vision is temporarily suspended, and an impulse to fusion there- fore excluded, we may cause the one eye to overcome concave lenses either on distant or near fixation, and note how, with in- creasing strength of such lenses, the latent deviation alters in amount. As a rule, if the accommodation be induced in this way, instead of by approaching the object of fixation, it is found that convergence lags still farther behind accommodation. The extent of the difference between the accommodation brought into 25 m. 4ka. Fig. 207. l)lay in this way and tlie latent convergence associated with it differs somewhat in different people. On the whole, the relation thus manifested is more intimate in cases in which there is also a closer manifestation of that relation for the various distances of fixation. The greatest ettbrts of accommodation, however, are always associated with the closest relations of con- vergence. Fig. 209 shows the relation manifested between con- vergence and accommodation in a case in which concave len.ses u}) to 4'0 can be overcome without difficulty. This is an average case. The lagging of convergence is often more, rarely much mo AFFECTIONS OF THE OCULOMOTOR MUSCLES. less, at all events up to .'5 dioi»tre.s of accommodation (i.e., an amount wliich correspond.s to what is con.stautly being used for reading). Again, a similar test may be made for fixation maintained at a near distance, e.r/., \ metre. If further accommodative effort •2ma. (ma 2ma 3MJk. 4ma. 25m. Fig. 208 than that which is normally called for be induced by placing concave lenses in front of the eyes, a change in the latent convergence, manifested in association with accommodation, is found very similar to that which has just been referred to as taking place for distant fixation. It is inter- esting, too, to notice the effect of diminishing the accommodative effort by placing convex glasses in front of the eye. Fig. 210 shows the curve of latent convergence where accommodation has been accurately maintained for a distance of I metre, under efforts varying from to 8-0 D, by using +4-0, +3-0, +2-0, + 1-0, and 0, - UO, - 2-0, - 3-0, - i-Q respectively. The total RESULT OF TESTS. 511 change through these 8*0 diojjtres of accommodation is only 1 "7 metre-angle. This shows how very far the degree of mani- fested convergence, in the temporary absence of binocular vision, is from keeping pace with accommodation. The same result is got from the examination of the latent posi- tion in myopes and hypermetropes, with and without correction, for distant and near fixation. Considerable individual diti'er- euces are found in this respect, depending partly u})on individual peculiarities, and partly upon Avhether correction is constantly worn or not. On the whole, the difi'erence between the latent I.D. atSm. 2D. J.D. 4.D. I MA 2M.A. 3ma Ama \ \ \ \ \ .^ N. \ \ \ \ \ \ \ \ ""^ N \ \ \ V \ \ \ N \ N \ Fig. 209. position, with correction and without correction, is considerably less for distant fixation than for fixation of a near object. Often, indeed, there is practically no dittereuce on distant fixation. From a consideration of such tests as have just been de- scribed certain facts are sufticiently clear: (1) Along with greater and greater accommodative changes, however induced, some increase in the associated degree of convergence continually takes place ; (2) the manifest convergent movements associated with accommodation are usually much less when measured in metre-angles than the accommodation measured in dioptres ; and 512 AFFECTIONS OF THE OCULOMOTOR MUSCLES. (3) whenever the conditions necessitate an unusually great etibrt of accommodation, tliere is manifested a proiJortionately large change in the associated degree of convergence. Whilst then, and whether originally from habit alone or from some closer anatomical connection in the nerve centres, there is clearly an evidence of association between accommoda- tion and convergence, it is doubtful if in cases in which binocular AT-25M. G I.D 2.D 3.D 4.D 5.D G.D 7D 8.C \ \ s \ \ IMJV \ 2 MA \ \ s \ '\ 3 MA s, "NJ ^"^ ■^ \ 4MA *-T *s_ \ ^^ 5ma ^ \ \ \ 6M.A. X \ s \ s s ^.. . \ 8 MA. s \ Fig. 210. vision is a constant occurrence, the latent position can ever afford a trustworthy measure of the intimacy of this association, so far as the actual impulses are concerned. If the latent position be taken after long occlusion of one eye, a difference may generally be found as compared with that resulting from temporary occlusion. This difference, too, is always indicative of a closer association between the two im- jtulses. Any method of testing based upon prolonged occlusion LATENT POSITION IN STRABISMUS. 513 of oue eye camiot be conveniently applied in niany cases. More ID 2.0 J,D 4J) S.D G.D 7.D 8JD 2 MA 5M.A 6IVU\ 71VLA 8MA suitable material is presented by cases of strabismus. Figs. 211 and 212 show the latent position found in two cases of strabismus. Fig. 211 represents the case of a hypermetrope, a^t. 34, with a per- manent convergent squint of 1"5 metre-angle, and hypermetropia of I'O D. The position was taken at 5 metres. Accommodation was in- duced by concave lenses. The 2-0 to G"0 lines correspond therefore to overcoming -TO to -5*0, whilst the zero and TO lines are respectively representative of the accommodative effort exerted with 1 -0, and without any glass. 33 514 AFFECTIONS OF THE OCULOMOTOR MUSCLES. The extent to which an association between convergence and accommodation is here manifested is very striking, wlien com- pared with such a case as that shown in Fig. 210. The excess of convergence over accommodation, when the limit of accommoda- tive power is ai>proached, is also well marked. Fig. 212, again, represents the case of a myope of 3 '5 D, set. 10, with periodic divergent strabismus and amblyopia. The latent position was taken for fixation at \ metre, for which dis- tance only 0"5 of accommodation was necessary. Further AT-25M • 50 I5D 2-5D 3-5D 450 N \ N, \ \ S \ \ ^ N X, \ % \ » N, X \ X, \ X, \ X \ X \X nX \ \ \ \ Fig. 212. accommodation was induced by concave lenses -UO to — 4"0; here, also, there is a well-manifested association between converg- ence and acconunodation. In many cases of divergent strabismus, with myopia, such an association is not seen at all ; as unless there is binocular vision on near fixation, convergence is gradu- ally altogether unlearned. The study of the relative directions assumed by the visual axes on the temporary exclusion of binocular vision reveals the fact that fusion has always something, and generally a great deal, to do to correct and counteract the association which exists PARALYSIS OF OCULAR MUSCLES. 515 between accommodation and convergence. The association is manifested, as we have seen, in quite a difterent manner where, as in strabismus, binocular vision has been given up. But it is certainly open to doubt whether the connection manifested in such cases indicates the real nature of the association of the two impulses. It is evident, however, that there exists a powerful tendency towards the persistence of any particular state of in- nervation to convergence, which is constantly being called for in the interests of binocular vision. Thus the approximate or complete parallelism of the axes, which is found as the latent position for distance in all states of refraction, must be looked upon as the expression of the persistence of that state of inner- vation which is so constantly called for by the requirements of bin- ocular vision. The parallelism only exists in cases where associ- ated lateral and convergent movements are constantly being made use of in a normal manner. In the case of near vision, though the same tendency to retain the accustomed position is shown, it is shown, as a rule, to a less extent . The retention is most com- plete in those who are in the habit of reading, or otherwise using their eyes for near work, unintermittently for hours at a time. Paralysis of Ocular Muscles. When the action of any muscle of the eye is weakened, there is a tendency for that eye to lag behind when an attempt is made to turn both eyes in the direction of action of the weakened muscle. In the case of paralysis of either of the lateral recti, the defect in the associated movements of the two eyes to the one side is often quite appreciable on mere inspection, it being evident where the weakness lies, though, if there be only slight pai'esis, such defect may escape observation. In such cases, and mostly in the case of paresis of other of the oculo-motor muscles, the diagnosis is most readily, or it may be only, arrived at by a consideration of the diplopia to which the condition gives rise. If in any position of fixation the two visual axes do not cross on the object fixed, there is diplopia for that jjosition, pro- vided there existed previously true binocular vision. The diplopia is more and more mai-ked, i.e., the distance of the double images apart is greater and greater, the farther the object fixed lies towards the boundary of action of the weakened muscle. To facilitate the examination of the nature of the diplopia in any case, it is customary to place a coloured glass — most con- veniently a dark red glass — in front of one eye, and cause the patient to look with both eyes at a candle flame held^in the ob- 516 AFFECTIONS OF THE OCULO-MOTOR MU.SCLE8. server's hand at a distance of a few feet from the patient. This plan not only renders the diplopia more ajjparent to the patient, hut also indicates to the observer, from the statements elicited from the patient as to the relative positions of the coloured and uncoloured images, tliat of the eyes themselves. The coloured glass should be held in front of the fixing eye, -which is at the same time generally, though not always, the sound one, so far as the muscular defect is concerned. The image in the fixing eye being a fovea! one, is always more distinct than the more jteripheral image in the deviating eye. Consequently there is produced, when the coloured glass is held in front of the fixing eye, a less considerable difference in the strength of the two im- pressions than would be the case if it were held in front of the deviating one, and on this account there is less tendency to sup- press the image of one eye, which Avould render the examination of the diplopia impossible. If one eye is directed straight forward, all objects to the outer side of that fixed by it have their corresponding images on the inner side of the retina, while objects to the nasal side form images on the outer side of the retina. In order to be able to see these objects distinctly, we should have to move the eye out- wards or inwards respectively, and to an extent varying ■\\ath the position of each object. We gradually and unconsciously acquire the knowledge of the relative position of objects from learning, without being aware of it, what amount of innervation is necessary to effect and regulate this directing of the visual axes. We are accordingly in the habit of ]jrojecting images lying on the nasal side of the centre of the retina away from the middle line, and images lying to the temporal side of the centre of the retina medially. At the same time, and for a similar reason, namely, as the result of the acquired knowledge of the normal position of the eyes, the fields of vision, whatever be their relative position, are, as a rule, mentally superposed, con- sequently the vi-sual axis of a deviating eye is mentally projected so as to meet that of the fixing eye on the object fixed. From these two laws it follows that when the position of the deviating eye is one of too great convergence, the image on it of the object fixed by the other eye, falling to the nasal side of the retina, is projected so as to appear displaced, with respect to the image of the fixing eye, in the opposite direction to that of deviation : therefore, in the case of too great con- vergence of the right eye, to the right, and of the left, to the left. This form of di})lopia is called homonymous, as the image to the right corresponds to the right eye, and that to the left to PARALYSIS OF OCULAR MUSCLES. 517 the left eye. Again, if the deviation is one of too great diverg- ence, the eccentric image is for a similar reason projected, as before, in a direction opposite to that of the deviation, which gives rise in this case to what is called crossed diplopia, as the image of the right eye appears to the left, and that of the left to the right. Therefore, relatively, too great divergence with respect to the object fixed gives rise to crossed diplopia. Where there is a paralysis or paresis of any of the muscles Avhicli turn the eye outwards, there will be, for certain positions of fixation at anyrate, relatively too great convergence, and consequently, where the other conditions favouring double vision exist, the diplopia will be homonymous. The pareses in which we might therefore expect to find homonymous diplopia are those of the external rectus, and also of either oblique muscle. Again, when there is paralysis or paresis of any of the muscles which move the eye inwards, there is for certain posi- tions of fixation relatively too great divergence, and consequently the existing double vision is crossed. The pareses in which we find crossed diplopia are therefore those of the internal, superior and inferior recti, muscles. Besides lateral displacement of the double images, two other directions of displacement require attention, namely, the vertical and the torsional displacements. When one eye lags behind in an attempt at associated vertical movement, or, in other words, when its visual axis deviates from the point fixed, either upwards or downwards, the image on it of the point which is fixed l)y the fovea of the properly directed eye appears displaced in space in a direction, with respect to the image of the properly directed eye, opposite to that of the deviation — i.e., when the deviation is downwards, the image of the deviating eye ai)pears higher than that of the other ; and when the deviation is upwards, the image of the deviating eye is lower than the other. To the lower eye corresponds, then, always the higher image, and vice versa. The explanation of this is exactly similar to that which has just been given in the case of lateral displacement. The indi- vidual is, so to speak, unconscious of the position of the deviating eye, which he imagines to be directed in accordance with the hitherto existing laws of association. He therefore projects its images, not in accordance with their actual positions, but with the positions into which the associated impulse should have brought them, had there been nothing preventing the eye from responding to that impulse. The same misinterpretation of the actual position of the :.ls AFFECTIONS OF THE OCULO-MOTOR MUSCLES. deviating eye explains also the torsional displacement of its projected image which is found for definite jtositions of fixation in some forms of paresis. When, owing to the paralysis or paresis of a muscle, the torsional effect which its action should R Fig. 213. — Sliow.s maimer of jirojeL'tioii in almoi'iiial couvergeuce of right eye. 0, poiut fixed by left eye ; m n d, direction of visual axis of right eye, ?«, its fovea, n, its nodal poiut ; .r, position of image of in right eye ; tn' n' 0' , position in which individual unconsciously supposes right eye to be ; ./;' n' 0\ direction in which right eye projects image of ; ni :i:=m' .'/. — After Alf. Graefe. produce on the position of the eye is absent or incomplete, the twisting of the projected image is also in the opposite direction of the deviation : thus if, instead of being twisted to the right, the eye remains untwisted, i.e. remains behind the other to PARALYSIS OF OCULAR MUSCLES. 519 the left, as far as torsion goes, tlie projected image is sloi)ecl to the right. The manner in which the image of the deviating eye is usually projected explains, too, a symptom which is often met with in fresh cases of paralysis or paresis, namely, a giddiness Fig. 214.— Shows manner of projection in abnornial divergence. Lettering as in Fig. 213. ,>;' ic' 0', direction in wliich image of is projected by right eye. and uncertainty in the movements of the individual. If the patient be made to fix with the affected eye whilst the other is occluded, he sees everything to the side of the i)aralysed or paretic nuiscle displaced in the direction of action of that muscle. This may be readily demonstrated by causing him to grasp cpiickly with the hand (jf the .same side at the object 520 AFFECTIONS OF THE OCULO-MOTOU MUSCLES. wliicli lie attempts to fix with the aftected eye, when it is found tliat lie grasps too far in the direction of action of the weakened muscle. Jn order that this experiment should suc- ceed properly, his hand must have lx!en previously out of view, and the attempt at grasping be made quickly, otherwise it is evident that the conditions for rectifying the error of projection are introduced. The giddiness disappears when the affected eye is occluded, but not if the sound one is occluded. For a similar reason, it is evident that the difficulties introduced by paresis of the ocular muscles are greater when the affected eye is used for fixation. When this is the case, there is at the same time, when double vision exists, a greater separation of the double images than is the case when the sound eye is the fixing one, because the unwonted effort required by the affected eye for fixation of objects lying in the direction of the action of paretic muscle is associated with a greater movement in the same direction of the other eye, for which there exists no im})ediment to movement in that direction. The deviation of the sound eye, when the aftected one is used for fixation, is called the secondary deviation, as distinguished from the primari/ deviation of the affected eye when the sound one is used for fixation. The secondary deviation is evidently a measure of the degree of abnormal eftbrt required by the weakened muscle to evolve the [)ower required of it. The difference, in the case of paralysis, between the })rimary and secondary deviations constitutes one of the essential points of distinction between paralytic and ordinary or concomitant squint. Two circumstances may aff'ect the position of the double images to which })aresis of a muscle gives rise — (1) The previous position of equilibrium of the eyes ; and (2) the so-called secondary contracture of the antagonistic muscle. If the natural position of equilibrium be one of considerable divergence, the homonymous displacement of the double images in paralysis of an obli(|ue muscle may not appear ; if it be one of considerable convergence, on the other hand, the crossed character of the lateral displacement in i)aralysis of the superior or inferior rectus may not be ])resent. When, again, there is a so-called secondary contracture of an antagonistic muscle, the area over which the diplopia becomes manifest in any case is extended, so that instead of merely existing in the direction of action of the weakened muscle, it extends over more or less of that of the antagonist as well. The occurrence of a secondary contracture is not altogether dejiendent on the degree of the primary defect. PARALYSIS OF OCTTLAR MUSCLES. 521 When the secondary contracture is marked, there is not so frequently diplopia. Secondary contracture in ocular paralysis is not analogous to contracture of muscles elsewhere in the body. There is, for in- stance, no fixing of the eye in one position ; it is free to move in the direction opposite to that of the supposed contraction. The term is obviously a misnomer. The cause of the prepondei-ating action of the one muscle in any case is, in fact, the alteration produced in the relative innervation of the antagonistic muscles, owing to the loss, gradual or sudden, of the tonic innervation of the paralysed or paretic muscle. It is not always easy to tell, without determining the nature of the diploi)ia, for which eye the paresis exists. This is, how- ever, readily done by noting to which eye that image belongs which lies farthest in the direction in tvhich Jixation is attemjJted. That eye, therefore, lags behind, and does so owing to a weak- ness of the muscle which should move it in that direction. The image which appears in the wrong place is often recog- nised by the patient himself as the false image, that which is seen in its proper place as the tr^ie. As the sound eye is gener- ally used for fixation, the false image is at the same time most frecpiently less distinct than the true one, corresponding as it does to a }»eriplieral retinal impression. There may be paralysis or paresis of one or more ocular muscles without any diplojjia. There are several reasons for this. When a deviation of the axis exists for some definite positions, and yet does not give rise to the di}iloi»ia which should characterise the strabismus, this is either because the image of the deviating eye is suppressed, or because the patient has acquired the habit of jjrojecting the images falling on the deviating eye in accordance with the position it assumes, and not in accordance, as is the rule, with the impulse to associated movements. The first is the more connnon cause. But even when there is in no position any deviation, there may yet exist a i)aretic condition of one of the ocular muscles. Thus it often hapi)ens that the paresis is so slight that it can be overcome by fusion in the interest of binocular vision. This is, of course, most common in cases of paresis of one of the lateral nntscles, as the power of fusion is greatest laterally. In order to detect whether there is a hidden paresis of this nature, all that is necessary in the case of the lateral muscles is to place a prism, with the base directed exactly upwards or downwards, in front of one eye, and note whether there is (1) any lateral displacement of the resulting 522 AFFECTIONS OF THE OCULO-MOTOll MUSCLES. cli)vil)le iniagt! in addition to the vertical displacement i»roduced by the prism ; and (2) whether the lateral displacement in- creases to one side and diminishes to the other. A lateral displacement which did not alter in extent to either side would, of course, not indicate a paresis of any particular muscle, but merely the position assumed by the eyes for fixation at the distance at which the test was made when deprived of the regu- lating intiuence of fusion. Relative frequency of different ocular paralysis. — Of the three nerves which suj)ply the muscles of the eye, the third and sixth are more frequently paralysed than the fourth. If we consider the relative frequency of the occurrence of paralysis or paresis of isolated muscles, we find that that of the external rectus is the most frequent. Next in order, and about half as frequent, is an isolated paresis of the superior oblique. Then come the paresis of either the superior or inferior rectus alone, though these are much less frequent ; and, lastly, the isolated paresis of the internus and of the inferior oblique, the latter of which is of very rare occurrence. Simultaneous paralysis of several muscles of one or both eyes. — Besides the isolated paralysis of the nerves which supply the muscles of the eye, or of the twigs supplying special muscles, we meet with all possible varieties of more comjjlicated paralysis in one or both eyes, the diagnosis of which can be generally readily enough made from a consideration of the double images. The most common combination is a simultane- ous weakness of several or all of the muscles supitlied by the third nerve. An interesting form of complicated paralysis is the jxirali/sisof associated movements. It is characteristic of these cases of paralysis, when they occur in an uncomplicated form, that there is, with one exception {yide infra), an entire absence of diplopia. The reason of this is that the restriction exists to exactly the same extent in both eyes. The forms in which I have met with associated paralysis are : — 1. Paralysis or paresis of both eyes to the right, or of both eyes to the left. 2. Paralysis of movement of both eyes to either side. In all the cases coming under these two headings there has been retention of the power of convergence, and an absence of diplopia. 3. Paralysis or paresis of movement of both eyes upwards, without diplopia. i. Paralysis or jDaresis of movement of both eyes downwards, without diplopia. PARALYSIS OF THE EXTERNAL RECTUS. 523 5. Paralysis of both upward and downward movements, with retention of lateral movements and convergence. 6. Paralysis or paresis of convergence, with crossed diplopia for near objects. The last is by far the most common. Next in order of frequency, in my experience, comes the first, namely, acquired defective movement to one or other side. This is always due to a lesion of the sixth nerve nucleus of the same side. The most infrequent ai'e the cases in which associated movements in more than one direction are restricted paralytically. Occasionally there is jiaralysis of the same muscle or muscles on both sides. I have most frequently seen paralysis of both externi, but I have also met with paralysis of both interni, and of the tAvo inferior recti alone. Paralysis of both externi is often very incomplete — only a slight paresis. The diagnosis is easily made by observing a marked increase in the sei^aration of the homonymous double images on fixation to either side. Paralysis of the inferior recti is diagnosed, from paralysis of associated movement downwards, by the existence of diplopia in the secondary positions. Paralysis of all the external nuiscles of both eyes occurs either as one of the manifestations of gross cerebral disease or owing to disease of the nuclei of third, fourth, and sixth nerves — sometimes the two third nerves alone are paralysed. Paralysis of the external rectus, or sixth nerve. — When this condition exists, the power of abduction is more or less completely lost. If there has previously been binocular vision, and the paralysis is recent, there is homonymous diplopia, which almost invariably extends more or less over to the side of the sound eye. The double images increase in distance apart, the farther the object is carried to the side of the affected eye. For equal lateral distances from the middle line, the double images are generally farther apart for fixation below the horizontal plane through the eyes than for fixation above that plane. The reason of this is that divergence in the interest of fusion with the eyes lowered is more difficult, because rarely required, than with the eyes raised. At the same time the false image in the secondary positions is often slightly inclined from the true one above, and towards it below. This arises from the alwence of torsion, caused by the want of participation of the outward movement with the vertical movements of the eye. Fig. 215 gives schematically the positions of the double images. Paralysis of the right external rectus is more distressing than paralysis of the left, owing to its interfering more with reading. 524 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. Frequently the patient keeps his head rotated to the side of the paralysed muscle, and fixes oljjects straight in front of him with hLs eyes turned to the other side. In this way he effects a more useful disposal of the area of single vision. The lesion pro- ducing paralysis of the sixth may be central or peripheral, and the causes various. Paralysis of the superior oblique muscle, or fourth nerve. — In this paralysis there is more or less restriction in the power of moving the eye downwards, most marked when the eye is directed inwards. The diplopia exists only in the lower half of the field of fixation, unless the pre])onderance of the inferior R (^ i i I I Nl I I Fig. 215. — Position otdoul)le iiuages in paraly.sis of riglit external rectus. oblique or superior rectus, or both, is asserted, as is often the case. The diplo[)ia is homonymous, vertical, and torsional. The greatest vertical displacement occurs for fixation downwards and inwards ; the greatest torsional displacement, for fixation downwards and outwards ; the images slope towards each other. Sometimes the homonymous character of the diplopia is not marked, or the images may even be crossed and sloping from each other. This is owing to the coexistence of a latent divergence. Fig. 216 gives schematically the arrangement of the double images in the primary and secondary positions. (Compare with PARALYSIS OF THE INFERIOR RECTUS. 525 chart for inferior rectus.) Paralysi.s of the superior obHque causes ditficulty in moving about, especially in going down stairs. The patient generally holds his head downwards, and towards the sound eye, and thus effects a more useful dis- posal of the area of single vision. The lesion in paralysis of the fourth nerve is either peripheral or central, and the causes various. Paralysis of the inferior rectus. — Movement of the eye downwards is more or less restricted, mostly when turned out- wards. The diplopia exists only for the lower jiart of the field of fixation, except when there is a manifest preponderance of i^. S/NCL£ V/S/OA/ A/^£A " «^ M A ^i R J Fig. 216. — Position of double images in paralysis of right superior oblique. the superior rectus, or inferior oblique, or both, and is cros.sed, vertical, and torsional. The greatest vertical displacement is found for fixation downwards and outwards ; the greatest tor- sional displacement, for fixation downwards and inwards ; and the double images s\o\)C towards each other. Occasionally the diplopia, instead of being crossed, is homonymous, and the images slope away from each other. This is owing to the coexistence there of a latent convergence. Fig. 217 gives schematically the relative positions of the doulile images in the lower jiart of the field of fixation. (Compare with those of superior oblique.) The inferior rectus is seldom paralysed alone, 52G AFFECTIONS OF TTTF OCULO-^fOTOR MUSCLES. though frequently along with other muscles supplied by the third nerve. Paralysis of the superior rectus. — ^Movements of the eye upwards are more or less restricted, principally when it is turned outwards. Attempts to move the eye upwards are associated often with retraction of the upper lid, giving a staring appear- FiG. 217. — Position of doulile images in paralysis of right inferior rectus. Dijilopia in lower portion of field. ance. The diplopia exists only for the upper part of the field of fixation, except when there is a manifest preponderance of the inferior rectus, or superior oblique, or both, and is crossed, vertical, and torsional. The greatest vertical separation of the images occurs for fixation upwards and outwards ; the greatest torsional displacement, for fixation upwards and inwards ; and the images slope away from each other. When the eye is displaced Fig. 218. — Position of douVile images in paralysis of right superior rectus. Diplopia in upper portion of the field. in the direction of the antagonistic muscles, the diplo})ia, which extends to the lower part of the field of fixation, is then often homonymous. Fig. 218 shows the relative positions of the double image in the upper part of the field of fixation. (Com- pare with diagram for paralysis of inferior oblique.) The superior rectus is seldom paralysed alone, though often along with other muscles supplied by the thii'd nerve. PARALYSIS OF THE LXFERTOPi OBLIQUE. 527 Paralysis of the inferior oblique. — Movements of the eye upwards are restricted, es})ocially when it is at the same time adducted. Diplopia, unless there is a manifest preponderance of one of the muscles which rotate the eye downwards, only exists for the upper portion of the field of fixation, and is homonymous, vertical, and torsional. The greatest difference in height of the double images is seen for attempts at fixation upwards and inwards, the greatest torsion for fixation upwards and outwards, and the images slope away from each other. Fig. 219 shows the position of the double images in the upjier portion of the field of fixation. (Compare with those caused by paralysis of superior rectus.) The inferior oblique is almost never paralysed alone, though often along with other muscles supplied by the third nerve. Occasionally a paralysis of this muscle has been met with owing to the accidental detachment of its origin, caused by wounds Fig. 219.- - Paralysis of right inferior oblique, portion of field. Diplopia in upper about the inner angle of the orbit. I have seen three cases of traumatic paralysis of the inferior oblique. In two of these the accident happened in the hunting-field by falling against a bush, a twig of which caused laceration of the muscle origin. The third occurred to a medical man, who, in a fall from a bicycle, wounded the lower orbital margin by striking against the handle of the machine. Paralysis of the internal rectus. — There is more or less restriction of the inward movement of the eye. Diplopia, owing to manifest preponderance of the externus, stretches more or less over to the side of the field oi)posite to that of the affected eye. The diplopia is crossed, and the double images increa.se in distance apart as the object fLxed is carried to the side of the affected eye. In the secondary positions there is slight sloping of the false image as well. Paralysis of the internal rectus is one of the rarest forms of isolated paralysis, 'though it is often 5-J8 AFFECTIONS OK THE OCULO-xMOTOll MUSCLES. the muscle most completely weakened when the third nerve as a whole is ])aralyse(l. Paralysis of the third nerve. — There is more or less droop- ing of the upper lid, mydriasis, and defective accommodation. Movements of the eye inwards, upwards, and downwards are more or less completely abolished. The amount of possible downward movement is not only dei)eudent on the degree of paralysis of inferior rectus, but also on that of the internus as Avell. The more im{)erfect the adduction, the less does the action of the superior oblique in turning the eye downwards come into play. Dii)lopia exists all over the field of fixation, the false image lies below the true, and is sloped outwards both for fixation outwards and inwards. Paralysis of the third nerve is very common, and is often incomplete, occasionally one, though more frequently two or more, of the muscles being alone aftected, or more markedly aftected, than the others. The lesion may be central or i)eripheral, and the causes various. When there is complete paralysis of the internus, it is not always quite easy to be sure of the action of the superior oblique. Inward rotation, which should theoretically take place on attempting to move the eye downwards, is often conspicuously absent. It must not be inferred from this that the fourth nerve is also paralysed, as, owing to loss of tonic contraction in the upward rotators which are involved in the paralysis, the preponderance of the superior oblique has already led to torsion. If, however, there should be any appreciable torsion of the eye inwards when the attempt is made to look down, we may be pretty sure that the fourth nerve is not paralysed. The lesions (living rise to oculo-motor paralysis may be peri- pheral or central. Peripheral lesions are such as involve the nerve trunks or their branches, either in the intra-cranial or in the orbital portions of their course. Other orbital peripheral causes of paralysis may be lesions which directly impair the functional activity of the nuiscles themselves. Many congenital paralyses depend upon nuiscle defects. Orbital cellulitis and periostitis and tumours may affect either the nerves or the muscles, or both, and thus cause paralysis. The intra-cranial peripheral or basal lesions leading to paralysis are various. They may be traumata, as in rupture of the nerve trunks in fracture of the base of the skull. They may be inflammatory, of rheumatic, syphilitic, tuberculous, or other origin, and then be occasionally subject to recurrence. In many cases they are caused by pressure : from tumours, fibrous bands, blood clots, aneurysms, oedematous brain tissue, etc. LESIOXS CAUSING OCULAR PARALYSIS. 529 Central lesions, on the other hand, are those which involve either the nuclei of the oculo-motor nerves or the various fibres which, passing from the nuclei, are collected to form the different nerve trunks. Nuclear paralyses may be due to primary patho- logical changes in the cells, and these changes may be of various natures. They may ,lje, for instance, degenerations of more or less obscure origin, sometimes inflammatory ; or caused by cir- cumscribed sclerosis, which are then, however, usually mere localised patches, connected with a more widesjtread process of the same nature, as in tabes. Circulatory disturbances, lut-mor- rhagic and other, may be limited to the region of the oculo- motor nuclei. Various poisons, too, both ecto- and ento-genetic, may disturb more or less completely and permanently the vitality of the cells in this situation. Alcohol, — possibly also tobacco, — 'diphtheria, and diabetes are causes of this nature. Then, again, there may be direct pressure on the nuclei, or the fibres which pass from them, by tumours of the pons, intra- ventricular haemorrhages, or cerebral oedema. Nuclear lesion.s are usually the cause of the different varieties of aswciated ocular paralysis in which muscles which act together in the two eyes are deprived of their impulses to associated contraction. It is by no means generally easy to arrive at a correct diagnosis of the site of the lesion causing an oculo-motor paralysis. The points to be considered in attempting to do so are — (1) The manner in which the paralysis is distributed over the nerves of one or both eyes; (2) the completeness of the paralysis itself ; (3) the existence and nature of complications, such as optic neuritis, paralysis of the facial, sympathetic, and fifth nerves. In many cases of severe intra-cranial disease the ocular paralyses may be of secondary importance to the other symptoms. In some cases, and particularly in the case of orbital lasions, there may be little difficulty. One eye alone is then affected, and the restriction in its power of movement may he associated with exophthalmos, or with o[>tic neuritis on that side only. An intra-cranial peripheral causation may usually l)e inferred when all the muscles supplied by the third nerve, l)oth intra- and extra-ocular, are affected, or when several muscles of both eyes, w'hich are not associated nuiscles, are paretic, or, in the case of the implication of associated muscles alone, if the degree of the defect differs markedly in the two eyes. The existence at the same time of a double optic neuritis would, as a rule, justify the diagnosis, especially in the absence of febrile symptoms, of tumour pressing on the nerve trunks. 34 530 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. A nuclear causation would 1)C inclica,ted when, for instance, there was any definite associated defect of movement in the two eyes in some particular direction, or wlien in one or both eyes some or all of the external nuiscle l)ranclies of the third nerve were found to be paretic without any impairment in the activity of the ciliary and sphincter i)Ui)ilhe nuisclcs. Both as regards the jirognosis of recovery from the local ]>aresis and the chance t)f extension of the lesion to more vital parts, perijtheral causations are to be looked upon as less serious, in general, than nuclear ones. The main exceptions to this are cases of l)asal paralyses caused by tumour pressure, — in which, of course, the i)rognosis, though the nerve lesion is a peripheral one, is bad, — and the cases of toxic nuclear paralyses, especially post-diphtheritic, in which the prognosis is generally favourable. Occasionally we meet with congenital paralysis, the most common being ptosis and paralysis of one or both sixth nerves. Many of these cases are no doubt due to congenital nuiscular defects, and are not true paralyses at all. Our knowledge on this subject is, so far, very defective. The treatment of ocular paralysis should be general and local. When the })rimary cause of the paralysis — be it rheumatism, syphilis, or changes in the nervous system, or due to diphtheria or any other form of poisoning — is apparent, or when there exist sufficient grounds for suspecting any definite cause, the treatment found to be most efficacious in the particular affection should be at once adopted. Local treatment may be instituted on three lines — (1) Passive movements of the eye in the direction of the action of the weakened nuiscle ; (2) attemi)ts to induce active movements of the weakened muscle ; (3) operations calculated to bring about a more advantageous relative position of the paralysed muscle and its antagonist. Passive movements of the eye are made by seizing the conjunctiva with the fixation forceps and rotating the eye forcibly several times in succession, and once or twice daily, in the direction of the action of the Aveakened muscle. This can be done without causing any pain, by the use of cocaine. Attem})ts to induce active movement of the weakened muscle may be made in many ways. The simplest method is to cause the }»atient to fix binocularly some definite object, such as a printed word, and to carry this object gradually farther and farther in the direction of the area of double vision, whilst he is all the time making an efibrt to fuse the images of the two eyes, which tend more and more to separate. The tendency to fusion LESIONS CAUSING OCULAR PARALYSIS. 531 is sometimes so strong in cases wliere the internal rectus is paretic, that the strain which maintaining l)inocular vision entails is not only the cause of considerable discomfort, and even pain, l)ut may not improbably tend to retard the com})lete recovery. In such cases the patient may obtain great relief by the use of prisms of 3° or 4°, with their bases inwards in front of each eye. By this treatment the efforts of fusion are suji- ported and the strain lessened. Electrical stimulation of the weakened muscle, either by the constant or induced current, is recommended by many, and is occasionally of use. One pole is brought in contact with the forehead, and the other with the clwsed lid over the affected muscle. There is a great tendency for the i)aralysis of ocular muscles to disappear more or less suddenly, and after having existed for a longer or shorter period. Some cases, indeed, only last a few days. Operative interference should not be thought of until the condition has remained unaltered for a sufficiently long })eriod to render impossible any improvement by other means. Treatment by operation is only suitable in a small proportion of cases of paralysis of oculo-motor muscles. Interference of this nature should in the first place be deferred until a full year has passed since the onset of the paralysis. The advisability of operating will then depend upon whether the affection of innervation of the ocular muscle is the main or only symptom present, or whether it constitutes merely one symptom among many others indicative of serious cerebral disease. In the latter case nothing should be done ; in the former, if one muscle alone is weakened, or if the paresis is only marked in the case of one mu-scle, it is sometimes possible to improve matters more or less considerably. As isolated paralyses of the muscles supplied by the third nerve are of comparatively rare occurrence, it follows that the cases which most frequently otfer a chance of im}>rovement by operation are persistent cases of paralytic weakening of the external rectus and of the superior oblique. Cases of paresis of the external rectus of one eye are not only amongst the most frequent, but fortunately at the same time those for which most can be done by operation. In such cases the operative effect can be regulated with greater nicety, as, just as for concomitant convergent strabismus, the improvement in the I'elative jjosition of the eyes can be produced by the combination of tenotomy of one or both internal recti with the advancement of one or both external recti, according to the degree of the defect to be recti- fied, while there is besides a greater natural tendency, as has 532 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. already been explained, to the fusion of the double images, which frei|ucMit]y heightens the ettect of a suitable oiieration. 'J'lie cast's for which operations may be i>erformcd present considerable differences with respect to the comiileteness of the remaining paralysis, as well as the degree of manifest preponder- ance in the action of the internal rectus or antagonist muscle ; the extent of the tendency to fusion nuist also be taken into consideratif)n in the selection of what o{>eration or operations should be i»erformed in any given case. The main object of any operation is to displace the area over which double vision exists as much as possible to the side of action of the [)aralysed muscle. In all cases, therefore, in which some power has been retained by, or restored to, the external rectus, it will generally be possible to effect this, to an extent which is practically sufficient, by correcting the degree of convergent squint which exists for the fixation of objects in the middle line ; while the improve- ment thus ol)tained will be more complete the greater is the degree of such remaining power and the greater the desire for fusion. Cases of persistent }taresis of the superior oblique do not lend themselves to such complete readjustment, as it is impossible either properly to advance the paretic muscle or to weaken the mechanism of rotation which is antagonistic to that produced by the superior oblique, as that could only be effected by tenotomy of both the inferior rectus and the inferior oblique, the latter of which cannot be satisfactorily done. Nevertheless, by tenotomy of the inferior rectus of the other eye a very con- siderable favourable displacement of the area of diplojjia can be obtained in suitable cases. Spasms of Ocular Muscles. Spasmodic contractions of single oculo-motor muscles ai"e not only of extremely rare occurrence, but owing to their incon- stancy they are very difficult to diagnose. A much more common occurrence is a spasm of associated movement. In consequence of cerebral irritation, to account for Avhich there may or may not be some definite lesion, a forcible deviation of the eyes takes place in some particular direction — to either side, or upwards or downwards, or it may be a si)asm of the con- vergent movement of the two eyes. Spasm of convergence is not altogether rare. I have seen many cases. The condition is characterised by homonymous diplopia, Avith a diminution in the separation of the double images on fixation to either side. I CONCOMITANT RTRABTSMLTS. 533 As a rule it does not last many weeks, and is besides subject to variation in degree from day to day. The approximation of the double images to either side shows that the same degree of con- vergence is not maintained as the eyes move in association laterally. The effect of an irritation of the converging centre appears, in fact, to be to withdraw the relaxation of convergence beyond a definite point (the position of which is subject to variation) from the control of the will, and yet to leave the play of convergence, as the eyes move from side to side, to be effected in a hal)itual manner. It is similar, in fact, to the convergent movements which would take place if, on attempting to fix a more distant object moved from side to side, the eyes kept converged on points in a plane which lay nearer to them. At other times one meets, and mostly in cases of severe cerebral disease, with what has been called a disjunction of the co-ordinated movements of the eyes, in which the movements of the eyes appear to be greatly or entirely independent of each other, and to be at the same time deprived of volitional control. No general lines can be laid down for the treatment of such cases of associated or dissociated involuntary movements. Each case has to be considered for itself, but the im^wrtant point to remember is that they are by no means invarialjly indicative of serious cerebral disorder. Concomitant Strabismus. In the normal state of the eyes, when any object is looked at, the visual axes of both eyes are directed simultaneously on the same i)oint of the object. There is therefore sinuiltaneous fixation with both eyes. When only one eye is directed towards, or fixes, the object engaging attention, while the line of vision of the other crosses that of the fixing eye, either in front of or behind, or above or below it, there is said to be squinting, or strabisnuis. In the scientific acceptation of the term there can only be strabismus of one eye at a time, as it is clear that one eye must always, when it is possible at all, lie directed on the object looked at. Bilateral deviations and conditions of vision which render this impossible do not come under the categoi'y of straljismus. According to the direction assumed by the axis of the devi- ating eye, we have to distinguish between strabisnuis conver(/ens and divevf/ens and strabisnms surKum vert/ens and deorsii/n veiyens. The vertical deviations, upwards and downwards, though often combined with lateral deviations, are rare alone, 534 AFFECTIONS OF THE OCULOMOTOR MUSCLES. and are consequently of less piaetical inijiortance. They fre- quently remain after the lateral deviations have been corrected by operation. Convergent and divergent squints are connnon. When there is for no distance of fixation, either near or remote, a coincidence of the axes of vision, the strabismus is said to be absolute. When both eyes are projierly directed on fixing a near object, but one axis misdii'ected when a distant object is looked at, or when the misdirection of one axis takes place only on fixation of a near, but not of a distant, object, the strabisnnis is said to be relative. The strabismus may be constant or intermittent. It may always be confined to the one eye, — i.e., it may l)e unilateral, — or it may be alternating, when ol)jects to the one side are fixed by the one eye and to the other side by the other eye. It may or may not be associated with diplo})ia. As we have already seen, besides manifest strabismus, similar deviations are found to occur when one eye is occluded. There is then said to be a latent strabismus. The consideration of latent forms of strabismus is of importance, as they may under certain circunistances become manifest, or they may — though by no means so frequently as was at one time supposed — give rise to pain or discomfort : to that form of asthenopia which is called muscular asthenopia (see p. 556). ^lere inspection is not always sufficient to enable us to diag- nose a squint, as on the one hand there may be a slight deviation without its being api)arent, and on the other hand there may ai)pear to be a deviation when in reality both eyes are ju'operly directed. This may occur either when the eyes are not fixing the object which it is sui)posed they are fixing, or when the angle between the optic and visual axes is considerably larger or smaller than usual. Thus in hypermetropia an apparent divergence is due to an abnormal size of this angle ; whilst in some myopes a negative value of the same angle gives rise to an apparent convergence, which is sometimes extremely marked. It is necessary, therefore, in some cases at anyrate, to adopt the following method of testing whether there is or is not any squint. The patient is made to fix some distant object ; whilst he is doing so, the observer covers one eye, and notices whether the one which remains uncovered makes any movement in any direction. The patient is then again made to fix the same object, and his other eye is in the same manner occluded by the observer's hand, and any movement of the uncovered eye looked for. A similar test is then made for the fixation of a near CO^TOMITANT STRABISMUS. 535 object — at 10" from the eye. If the one eye has been mis- directed while both were open, and if it at the same time is in possession of sufficient visual acuity for central fixation, it will take up the fixation of the object looked at as soon as the fixing eye is occluded from vision. In order to do so it will have to make a movement in a direction exactly opposite to that in which it previously deviated ; so that a movement outwards of the other eye, on occlusion of the fixing one, is a proof of the existence of manifest convergent strabismus ; a movement in- wards, of manifest divergent strabismus. If the movements just described take place both for fixation of near and distant objects, the manifest strabismus is diagnosed as absolute ; if only for one or other, as relative. Care must be taken that the occluding hand is not transferred too quickly from the one eye to the other, which would cause a difficulty in distinguishing which was the squinting eye. Time must be allowed for the fixation to take place in the way in which it is ordinarily effected. If the conditions of fixation be the same for both eyes, the squint is almost invariably trans- ferred from the one eye to the other — i.e., the occluded eye, whether it be the one usually enqjloyed in fixation or not, is misdirected. This can generally easily be seen by observing the position which it assumes behind the occluding hand. The fact is, that although the defect is one rendering the position of the two eyes either too convergent or too divergent relatively to the distance of the object looked at, it necessarily only becomes apparent on the one, as the other has to maintain a proper direction of fixation. A truly alternating squint presents the following character- istics. If either eye, by first covering the other with the hand, be caused to fix an object in the middle line, i.e. straight out from the nose, it subsequently remains for an indefinite period, after removing the occluding hand, in the position of fixation. It is evident that it is immaterial to the individual which eye he makes use of for fixation in this i)osition. Again, on moving the object of fixation to the right, it is fixed by the left eye, whilst the right eye fixes it when situated to the left of the middle line. Both eyes have equal, or very nearly equal, vision, and are often emmetropic. The ordinary squint differs from the paralytic squint in this respect, that whereas in the latter the extent of the deviation increases in certain directions, it remains in the former the .same for all directions. For this reason it is cA\\in\ concomitant. The degree of concomitance, too, as measured by accurate tests, is 536 AFFECTIONS OF THE OCULO-MOTOK MUSCLES. found to be very complete. In concomitant, as well as jjaralytic squint, there is often less convergence when tlie eyes are directed upwards, and more when they ai'e directed downwards, than when fixation takes place for ol)jects in the horizontal plane through the eyes. The ordinary laws of the transference of the squint from the one eye to the other when the fixing eye is occluded, and the equality of the ])rimary and secondary angles l)y which a con- comitant squint ditiers from a })aralytic stjuint, are not altogether without exceptions. When, for instance, there is a difference of refraction in the two eyes, the accommodation required when one eye fixes is ditferent from that which is required l)y the other for the same distance, and consequently the same associa- tion between accommodation and convergence leads to a differ- ence in the relative directions of the two axes of vision, according as one or the other fixes. A very common instance of this is the case where one eye is myopic, while the other is emmetropic. The emmetropic eye is used for distant fixation, and there is then, it may be, no squint. For near vision it is frequently, on the other hand, the myoj)ic eye which is used, while the other diverges. If, however, the niyojuc eye be occluded, and the emmetropic one used for fixation, the secondart/ deviation (behind the occluding hand) is either considerably less or absent alto- gethei'. Often there is found to be in such cases divergence both for near and distant vision, the myopic diverging in distant fixation, the emmetropic in near. Sometimes, where the one eye is hypermetro])ic and the other myopic, convergent strabis- mus may exist for distant and divergent for near fixation ; and in these cases there is not only not the ordinary transference of squint from one eye to the other, but there is instead convergence when one eye is occluded and divergence when the other is occluded. We must, therefore, in any case, look for the ex- planation of deviations from the typical conditions in the state of refraction of the two eyes. What are the different facts to be noted in connection with convergent strabismus, and how are they to be explained 1 In the first place, the strabismus is not congenital. It usually develops between the ages of two and four, though in some cases it shows itself earlier, and in not a few later. A congenital convergent squint is of a different nature from the ordinary squint, and is due to })aresis of one or both external recti. In all such squints it is easy to distinguish two elements — a pet'inanent one, constant in amount ; and an accommodative one, or an increase of the deviation which only occurs on accommoda- CONCOMITANT STRABISMUS. 537 tion, and wliicli is greatest for tlie fixation of near ol)ject,s. The accommodative degree of squint remains practically tlie same always for the same distance of fixation. The degree of the permanent element, on the other hand, increases with time up to a certain extent, and then remains constant, sometimes again diminishing in later life. In a very considerable proportion of cases of convergent stra- bismus the eyes are hypermetropic. The proportion in wliich this is the state of refraction is greater the younger the individual. On the other hand, but a very small proportion of hypermetropes scjuint. It is not uncommon to find in a family of hypermetropes of much the same degree, some who s(|uint and some who do not. In the great majority of cases there is found to be, in adili- tion to hypermetropia, or independently of that refractive error, defective vision of the squinting eye. The defect is usually con- siderable, though it varies in amount in ditt'erent individuals. It is rarely so great as to lead to eccentric fixation when the squinting eye is used on the occlusion of the other. As a rule, therefore, the squinting eye takes up fixation when the one usually fixing is covered. In some cases, indeed in most, in which the eyes are equally good, the squint is not unilateral, but alternating, and then the right eye is generally used for fixation to the left, and the left eye for fixation to the right. Sometimes the strabismus is only periodic, and may even appear with tolerable regularity every second or third day, disap}>earing in the interval. There is then, generally, binocular vision, and consequently di})loi)ia, during squinting. A periodic squint may, however, exist where binocular vision is impossible, owing to great defect of vision of the one eye. Although a convergent squint usually develoi)s slowly and gradually, it does sometimes happen that it makes its apjjearance quite suddenly. The great characteristic of ordinary squint is its concomitanci/. In all convergent squints there is a more or less evident restric- tion of the outward movement of both eyes, lint this restriction is never so great as the squint, i.e., the angular defect in rotation outwards is not so great as the permanent angidar deviation from the direction of correct fixation. In 2»oi>it of fact, its size is but a small fraction of that of the stpiintiiig angle. The refraction in a convergent scpiint is sometimes emme- tropic and occasionally even myopic. The so-called stra/>i.'(inus converyens myopicufi differs from the ordinary concomitant 538 AFFECTIONS OF THE OClJLO->rOTOH MUSCLES. variety, in that no increase in the amount of .s(juint takes place on near fixation. In fact, the al)nornial manifest convergence at first only exists for fixation beyond the far-pcjint, and is always a.ssociated with more or less troul)lesonie diplopia. We have now to incpxire what it is that leads to strabismus. The proper explanation, in so far as the temporary accommoda- tive element of the squint goes, was first given by Donders. In his study of the amplitude of accommodation, Donders found it necessary to distinguish between the total and the relative ampli- tiule of accommodation, or the amplitude which exists for a definite degree of convergence. Up to convergence on the binocular near-point there exists for every degree of convergence an amplitude of accommodation, part of which is what Donders termed the negative portion, — that is, all lesser degrees of accommodation which can [tossibly be associated with any particular degree of convergence, — and part of which he called the jiositive portion, which includes all the greater degrees of accommodation which may possibly be associated with the same state of convergence. Any degree of accommodation ou.tside this range is not compatible with the binocular fixation of objects situated at the distance on which the eyes converge. Donders further found that accommodation can only be sustained for a distance for which the positive portion of the relative range of accommodation is not too small, as com- pared with the negative portion. A hypermetrope has already to make an effort of accommoda- tion in order to see distinctly at a distance. He therefore begins convergence with a defect of accommodative power, so that with increasing convergence his amplitude of accommoda- tion proves sooner insufficient than in other states of refraction. Although he becomes, from habit, accustomed to associate a high degree, it may be, of acconmiodation with a slight amount of convergence, the positive portion of his relative range of accommodation may, to begin with, be too .small, as compared with the negative portion, for even moderate degrees of converg- ence. Fatigue further reduces the positive portion, and eventually abolishes it altogether. The binocular near-point, therefore, recedes from the eye. The strained feeling in or aljout the eyes to which this gives rise in hyi)ermetropes with binocular vision is what is now well known as accommodative asthenopia. Hypermetropes have a way out of this difficulty. They may renounce binocular fixation altogether, and this is what some, though only a small proportion, actually do. In doing so they CONCOMITANT STRABISMUS. 539 squint. The one eye only is used for fixation, and tlic axis of the other crosses that of the first nearer than the object fixed. The conditions under which this is most apt to take place are such in which the value of binocular vision is reduced by defective sight in one eye. The squinting eye is usually, as we have seen, found to have more or less defective vision. We may distinguish two forms of this amblyopia — (1) That in which central vision is retained ; (2) that in which fixation is eccentric. The defect is mostly due to some optical imperfection (irregular and regular astigmatism, corneal or lenticular opacities, etc.). Sometimes there are changes in the retina. The amount of visual defect originally existing in the first form, and which leads under favouring conditions to the giving up of binocular fixation, is generally supplemented by a further degree of weakness of sight, due to the habitual suppression of the images received by the S(juinting eye. This is what has been called amhlyopia from disuse. This element not unfrequently constitutes a very preponderating proportion, and sometimes, indeed, the whole of the existing amblyopia. It quickly disappears as soon as conditions are introduced which cause the attention of the individual to be directed on the impressions which the eye receives. It used to be a habit with ophthalmic surgeons to recommend the tying up of the fixing eye from time to time, in order that the use of the squinting eye should be practised, and thus amblyopia avoided. Indeed, this is still practised by some oculists. It is, however, but one of the remains of the many inconveniences which have been imposed upon squinters in the way of treatment, and is almost always quite useless. Of this I am convinced, from the result of an examination made many years ago in a large number of cases, where, for a week or more at a time, the fixing eye, if hy per metro} )ic, was disabled by the instillation of atropine, so that the patient was conqtelled to use the other for fixation. So soon as the fixing eye is liberated it takes up the work afresh, and the images on the squinting one are suppressed as before. ]Moreover, when from disease or accident to the eye which has })reviously been the master one, the other, from being the squinting eye, has to i)ermanently assume the position of the fixing one, it soon regains all the power which it possibly can, whether it has previously been practised so many hours each day or allowed to remain for years without being used. It would appear that in some few cases the tying uji of the fixing eye, by favouring diplo}»ia, when it is again uncovered, may facilitate the re-establishment of binocular fixation after (i[)t'ration. 540 AFFECTIONS OF THE OCULOMOTOR MUSCLES. A true permanent ;\nil)lyf)]tia from disuse is denied l)y some, because they say that, for instance, cases in which cataract has existed for thirty or forty years have not been found to have sufiered any loss of vision after a successful operation. There can be little doubt, indeed, that when central fixation has been once acquired, it is never lost by circumstances which merely interfere with the formation of distinct images on the fovea. It is otherwise, however, with cases in which cataract or any other opacity exists at the time that the suiiremacy of the fovea over other ]>arts of the retina is properly acquired. When the cause is removed, although a certain amount of vision is restored, there is no central fixation. This is always the case in dense congenital cataract, and often, too, Avhere there has been a long persisting dense corneal opacity following ophthalmia neona- torum. In the first case, after removal of the cataract, and in the second, even when all, or nearly all, the o^jacity has cleared away, the power of fixation is found to be defective, and always to remain so. In cases of unilateral strabismus which begin early in life, that is, during the first months, the squinting eye may be regarded as subjected to the same unfavoural)le condi- tions, as far as the acquirement of central fixation is concerned. Fixation with that eye is never called for, and therefore never acquired. The second form of amblyojtia, namely, that in which there is no central fixation i)ossi])le in the squinting e3'e, is in so far an amhlyopia from disuse, in that it is occasioned by disuse at a time when central fixation is usually acquired. Besides the parallel cases of absence of central fixation from early disuse given above, there is one circumstance which argues strongly for the correctness of this view. We find, as already said, very fre- quently unilateral andjlyoi)ia where there is no squint, but rarely if ever an amblyoina without central fixation, -i.e., of course in cases where there are no ol)jective signs to explain the absence of central fixation. Ajiart, however, from am])lyo})ia of one eye, there are some hypermetropic children who are so indifferent to the value of binocular vision, or rather one might say unobservant of, and not greatly inconvenienced by, the diplopia Avhich its renuncia- tion entails, that they readily adopt a squinting position in preference to asthenopia, and soon, by suppression, lose their diplopia. In this case the strabismus is mostly alternating. It is by no means easy to account for, why there should be such a total suppression of the image falling on the squinting eye. It is easy to satisfy oneself that that portion of the field of the squinting eye which is not coincident with the field of the CONCOMITANT STRABISMUS. 541 other eye is constantly aware of the impressions it receives. The fact seems to be simply that in cases where there has never been binocular vision, and in which usually there is considerable congenital amblyopia, diplopia does not exist, whatever l»e the explanation. One can hardly draw any conclusions iji cases of absence of binocular vision from what occurs when there has been binocular vision. In a number of cases, however, there is another reason for the absence of diplopia, namely, the fact that the squinting eye has acquired the habit of projecting its images in accordance with its position. Iir these cases there exists sometimes an imperfect form of binocular vision, but more frequently the absence of diplopia is due to the circumstance that, although there is no simultaneous elaboration of the two images of any object, still, whenever the squinting eye is conscious of its image, it is 2>rojected to the same place in space as that falling on tlie fovea of the properly directed eye ; that is to say, there may be simultaneous vision with both eyes, and yet no binocular fusion of images in the true sense. The two forms of suppression just referred to, although they hardly account for all the cases met with, are of interest so far as the conditions induced by operative interference are concerned. In the first form there is rarely any diplopia after o])eration, whereas in the second the operation gives rise to diplopia, of which the patient is more or less conscious. The new position of the eyes is not at first, or for some time, allowed for, and the position being relatively divergent, the persistence of the pre- vious habit of projection results in more or less marked crossed diplopia. In a few cases in which there is a considerable degree of latent convergence, but in which any manifestation of strabismus is always being prevented by the power of fusion, a manifest squint may suddenly develop. In such cases there is always diplopia, and the cause of the sudden manifestation of a hitherto latent condition is simply a loss of fusion power. This may l)e the result of some general bodily weakness, or of some cerel)ral disorder or disease. Thus, in children, continued irritation from teething or worms, or a sudden fright or severe fall on the head, not unfrequently leads to this manifestation of a hitherto latent squint (not always of a high degree), by directly interfering with the amplitude of fusion. Sometimes, again, fusion seems to be strained to such an extent, to prevent the manifestation of a latent convergence, that any undue fatigue will cause the appearance of scpiint, with diplopia. I have, for instance, seen a child who almost daily 542 AFFECTIONS OF THE OCULOMOTOR MUSCLES. got a diplopia fnun this cause, and was in tlie lia})it of going to sleep for an hour or two to get rid of it. I have seen others in Avhoni diplopia from concomitant convergent sijuint appeared periotlically. In one case this occurred every alternate day, so that one day's squinting provided tlie rest that was required to over- come 1 »y fusion the tendency to over-convergence for the next day. .+ So far, then, as we have traced the develoi)nient of squint, it has been that of the i)urely accommodative element, and the condition of the ocular muscles is in no way different from that which exists on binocular vision of a near object. The eyes, therefore, follow each other from side to side, just as they do when a near object at a constant dis- tance lies successively in direction or another from them. Fig. "220 shows this. It Avill be observed that it only differs from Fig. 197 in that the axes cross nearer than the point of fixation. The deviation (d) is twice the angle of the squint (s), or the angle of excess of convergence. And the im- l»ulse to this excessive con- vergence is equally divided over both eyes, in the same way as is the impulse to convergence necessary for fixing a near object binocu- larly in a line with the one eye. The eyes in the squinting position follow each other, too, from side to side, maintaining all the time the same deviation, just as they do Avhen fixing, biuocularly, near objects. This is how the squint comes to be concomitant. Further, just as the limit of outward rotation is reached sooner when the eyes are strongly converged in binocular fixation than when no convergence of the axes is required, so it is with CONCOMITANT STRABISMUS. 543 concomitant convergent strabismus. Tliis is the ex[(lanati()ii of the I'eal amount of restriction in the outward mobility f)f the eyes in a squint, which is often taken to lie an indication of weakne.ss of the external recti muscles. We have already seen that this defect in mobility outwards is always small when compared with the angular amount of squint. It is often ap[)arently greater in the squinting eye itself than can be accounted for in the manner just explained. The reason for this, however, is want of halnt. The squinting eye is never, under the conditions in which it is employed, directed very forcibly outwards, so that it requires an unwonted eftbrt of will to bring it to its possil)le limit in this direction. This limit can, however, ahvays be reached, although with more or less difficulty. We have still to explain the nature of the permanent element of a convergent squint. If the squint arises on accommodation, under such conditions as have been described, why should any squint remain on cessation of accommodation ■? As a matter of fact, there is only an accommodative squint to begin with ; the permanent element slowly develops. This latter has often been, and in fact is very genei'ally still, assumed to be due to structural changes taking place in the internal rectus of the squinting eye, whereby it becomes permanently shortened. Many authors assume at the same time a weakening or so-called insufficiency of the externus from disease. The evidences against such an assumed structural change taking place are so strong that to my mind they are absolutely conclusive. I need only i-efer to three of the most important : — 1. The temporary disapi»earance of the squint under general aniBsthesia, as well as its occasional gradual disappearance in adult life ; 2. The perfect concomitancy of the squint, even when it is mainly of a permanent nature ; and, 3. The absence of any anatomical demonstration of structural changes in the muscles. As to the first, one invariably sees, when the anaj.sthesia is sufficiently deep, that the effect of a tenotomy is much greater than it proves to be after recovery from ana'sthesia. Occasion- ally, too, a squint disappears altogether under anaesthesia, with- out operation. Stress has already been laid on the fact that any weakening of a single muscle must of necessity render concomitancy im- possible, and introduce conditions comparable to paresis. After tenotomy, for instance, concomitance is lost, and it is long before it is approximately regained. When the tendon of the right 544 AFFECTIONS OF THE OCULOMOTOR MUSCLES. internal rectus is sc]tarated from its attaclnnent to the sclera for convergent s(juint, the deviation, which before was the same for all directions, now constantly diminishes for fixation farther and farther to the left, and constantly increases for fixation farther and farther to the right. As to the third point, t(j which, however, I do not attach so much importance, it does seem significant that, notwithstanding the abundance of material which is to be found everywhere, no one has as yet brought forward either macroscopic or microscopic evidence of structural change in the muscles. To what, then, is the permanent element of the convergent strabisnnis due ? There can be little doubt that it is simply the gradual jjersistence of the increased and abnormal degree of convergence which is constantly l)rouglit into play Ijy the accommodative squint. This explanation, that the permanent as well as the acconmiodative element of a convergent strabismus is simply an increased innervation to convergence, w'as first given by Hansen Grut. The habit of converging leads gradually to a withdrawal, from the voluntary disposal of the individual, of a greater and greater amount of the amplitude of convergence. This he has expressed as follows : " The constant habit of con- vergence displaces the functional position of rest more and more inwards." The various facts just referred to point to convergent stpiint being entirely innervational, while the result of the examinations under different conditions of the latent position of the ocular muscles, in individuals who have retained binocular vision, points to the strong tendency that there actually is for con- vergence to persist in the manner in which it is constantly called into play. This being the case, it is not difficult to under- stand how, when convergence is overstrained from any cause, a permanent squint may develop in other states of refraction than hypermetropia. Certainly hypermetropia is much the most common predisposing cause ; but excessive use of the eyes may, in emmetropes and also in myopes, lead to a latent convergence, Avhich may in turn, though much less frequently, develop into a manifest strabismus. Over-convergence may, for instance, be induced in any condition of refraction by paresis' of accommoda- tion. The existing relation between accommodation and con- vergence is then interfered with, and the defect in accommoda- tive power unconsciously counteracted as far as possible by too powerful convergence. In the interesting variety of convergent strabismus in myopia the development may be followed through its different stages. COXCOMITAXT STRABISMUS. 545 An uncoi'rected or imperfectly corrected myope, who is in the habit of reading for long periods on end, finds that, for some time after he has ceased to read, distant objects, if seen sufficiently distinctly to attract his attention, appear double. At first this doubling of distant objects is only temporary. After some time it becomes permanent, because of the greater persistence of con- vergence, and because, vision being less perfect for distance, fusion does not exert so powerful an influence in overcoming this convergence innervation. After a longer and longer time the distance at which objects apj^ear in homonymous double images becomes shorter and shorter, and eventually a squint, at first only manifest beyond the far-point, has reached inwards until it exists for nearer fixation. In this variety of convergent con- comitant squint there is, however, always this difference as compared with the hypermetropic squint — that no increase in the angular deviation takes place for near fixation. To sum up in a few words, the nature of convergent con- comitant strabismus, we may say that it is the active state to which tlie equilibrium of the muscles leads zohen the interni have for long continued to receive an abnormal degree of innervation to convergence. In the treatment of convergent strabismus we have to take into consideration the fact that there is a tendency to a gradual disappearance of the squint as the patient grows older. When this does occur, it is seldom before the tenth year, and generally considerably later. The nature of the squint, too — whether periodic or constant, relative or absolute — must influence the treatment ; so also must the state of vision in the squinting eye, and the presence or absence of diplopia. Usually when some 0})erative measure is required, the degree of the ijermaneut squint will afi'ord an indication as to what operation, or com- bination of operations, is advisable. Though much can be done in some cases without operation, the cure of a convergent squint can usually only be thoroughly made by bringing about an alteration in the relative positions of the tendinous attachments of the lateral muscles. The perman- ent element of the squint can only be cured in this way, whilst that portion which is accommodative often disappears under the altered conditions brought about by propter correction of the existing error of refraction. When the squint has begun late and has not existed long, and where there is either sjjontaneous or easily elicited diplopia, with not too high a degree of amblyopia of the squinting eye and hypernietropia, an attempt should be made to cure it by causing the patient to wear glasses which as 35 546 AFFECTIONS OF THE OCULO-MOTOR MT^SCLES. nearly correct his liypernietroi)ia as he will tolerate. By keei)ing the accommodation paralysed for some weeks during the first wearing of the glasses, a pretty full correction may often after- wards be permanently worn without inconvenience, and a favour- able effect on the squint at the same time obtained. Owing to the difficulty of giving sjjectacles to young children, it is only a small proportion of cases in reality which admit of purely optical treatment. The continued use of atrojnne for the purpose of keeping the accommodation paralysed in both eyes, and thereby avoiding the tendency to squint, is sometimes useful in the case of quite young children. The operations of tenotomy of the internus, or advancement of the tendon of the externus, only produce an alteration in the mechanical consequences of the existing relation between the power of the two lateral muscles, but do not influence in any direct manner the cause of the squint. That is to say, that by displacing the attachment of the internal rectus backwards, or that of the external rectus forwards, the initial position of the eye- ball is altered in such a manner as to introduce a state of less convergence of the two axes. In this way the appearance is improved, while sometimes at the same time a resumption of function, Avhich the abnormal convergence rendered previously impossible, is permitted. Still the conditions of innervation, which are the cause of the squint, remain. Indirectly, the operative effect may lead to a true cure of the squint, by so far diminishing the abnormal muscular conditions that the further difficulties can be more or less readily overcome by fusion. When this happens, there must have pre-sdously existed binocular vision. The latent or dynamical deviation always remains. Whether the full permanent amount of the squint, or even more, should be corrected by operation depends on the age of the individual, as well as on the existence or not of circumstances which help to maintain the correction when once effected. The object of the operation is not merely to correct the position of equilibrium, but also to do so as far as possible in such a manner as shall admit of the accommo- dative and associated movements of the two eyes taking place in the normal way. In operating on children Avith hypermetropia and amblyopia of one eye, we should leave a little of the convergence uncorrected, owing to the possibilities of a change, in the direction of spon- taneous cure, taking place as they grow. In adults we may usually safely correct the whole amount of permanent squint, DIVERGENT STRABISMUS. i547 even where, as is often the case, there is no possibility of tlieir obtaining binocular vision after operation. In cases where tlie conditions favouring the simultaneous use of the two eyes are more advantageous, and at the same time the degi'ee of con- vergence associated with accommodation is clearly in excess of the normal, it is advisable to correct the full permanent element. In alternating squints, too, the whole correction should be made. When the convergent strabismus is associated with myopia, and is only relative, that is, only existing for fixation beyond a certain distance, care has to be taken that the correction of the squint for a distance does not give rise to insufficiency of con- vergence for near objects. Such insufficiency would either introduce relative divergence, with diplopia, for near vision, or asthenoi»ia, owing to the too great effort necessary to keep up the required amount of convergence. With correction of the myopia, I believe this danger need seldom be feared, so long as the position for a distance is not over-corrected. It is well, however, to determine beforehand whether there is any latent convergence at the reading distance. Should there be, there can be absolutely no doubt as to the advisability of performing a tenotomy. In the immense majority of cases the most successful operative intei'ference leads only to a removal of either the whole or, at all events, the unsightly portion of the abnormal convergence. The effect, so far as the eyes are concerned, is only cosmetic, and it is rare, comparatively speaking, that any true binocular vision results. Different methods have been devised for the purpose of stimulating the desire for fusion of the two images. Possibly these may in some cases be productive of the desired effect. In most cases they are, however, altogether useless ; and it is indeed doubtful whether, in the few cases in which binocular vision returns, the cure would not have been just as rapid without their aid. The best test for the presence of true binocular vision, or the accurate a^jpreciation of the third dimension, is that which is known as Hering's. When a prism of say V to 6°, with the angle directed inwards or outwards, held in front of either eye while the other is fixing any object, gives rise to a convergent or divergent movement of that eye, we may conclude that bino- cular vision of some kind exists. Divergent Strabismus. The most frequent state of refraction met with in this form of strabismus is myopia. But the preponderance of myopia is not 548 AFFECTIONS OF THE OCULO-^rOTOR iSIUSCLES. so maiketl liere as that of liypcnnetropia in concomitant con- vergent strabismus. It is a common enough occurrence in cases of more or less blindness of one eye, especially where the condi- tion causing the blindness has arisen in adult life. The diverg- ence develops, as a rule, slowly ; sometimes suddenly, but only then in some cases of sudden uniocular blindness. The degi'ee differs somewhat in different cases, but seems at the most to be from 10 to 12 metre-angles. It is never as high as that met with in complete internus paralysis, or after an unsuccessful tenotomy of the internus by Dieffenbach's method, a kind of case which is now very rarely seen. It is often at first, and may for long remain, relative only, i.e., there may be a manifest divergence for near vision, but no absolute divergence. Marked relative manifest divergence may be said to be peculiar to myopia. It is always associated with more or less complete absence of converging power. After the divergence has become so far established that it is absolute, and binocular vision is lost for all distances of fixation, it is found that little or no convergent movements can be made ; whereas not only is lateral mobility retained, but lateral move- ments take place in such a manner as to leave the deviation un- altered in extent for all directions of fixation. This characteristic concomitancy is, then, a })roof that there is no actual muscular defect. In fact, it is sufhciently evident that whereas, as in con- vergent concomitant strabismus, there is an active innervation to over-convergence, there is in divergent strabismus more or less complete absence of innervation to convergence. There is, therefore, no insufficiency of the interni, only an insufficiency of convergence. The convergent imjHilses are gradually lost from disuse. In the case of high myopia it is more or less difficult or impossible for the eyes to maintain a sufficient degree of con- vergence to fix objects binocularly at the far-point. Relative divergence, therefore, which is what is first manifested, gradually passes into the absolute form, because, owing to the defect of distant vision, double images are readily disregarded. The fact that under these circumstances, however, there can ever be absolute divergence, shows that the functional jjosition of rest of the eyes, in the constant enfeeblement or absence of convergent impulses, is a divergent one. The divergent deviation shows itself on one eye alone, for the reason that, binocular fixation being impossible, one of the two diverging axes must be directed on the object on which attention is directed. This necessitates a movement inwards of the fixing eye, with which is associated an outward movement of the other. DIVERGENT STRABISMUS. >49 This is shown in Fig. 221. The condition is, in fact, the exact counterpart of that shown in Fig. 220. Divergent squint differs, however, from convergent squint in another way. There is no active contraction of the externi in divergent, as there is an active contraction of the interni in con- FiG. 221. — Shows tlie manner in which the divergence is equally distributed over >>otli eyes, but owing to the requirements of fixation manifests itself in the one eye only. vergent, squint. Indeed, it is very doubtful if there is sucli a thing as innervation to divergence at any time. Except to restore the position of parallelism to the eyes which have heen converged, and this prol)ably takes i>lace in another way, it could serve no useful purpose in vision. 550 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. Divergent concomitant strabismus is, in fact, the passive stat^ to u'hich tfie equilibrium of the muscles leads tvlien the internal recti receive little or no innervation to convergence. Strabismus operations. — There are various methods in use of performing both tenotomy and advancement. These, whilst differing somewhat in minor de- tails, are the same in princi})le. Tenotomy is now always per- formed by cutting across the tendon of the muscle close to its insertion to the sclera, according to the method in- troduced by von Graefe. This permits of a certain degree of retraction, but the presence of Fig. 222. — a, Straliisnuis hook ; h, .strabismus scissors. other indirect attachments prevents the retraction being too great. The instruments required for the operation (Fig. 222) are a STRABISMUS OPERATIONS. 551 speculum, or a couple of Desmarres' elevators, fixation forceps, a pair of blunt-pointed scissors (curved on the fiat), and a strabis- mus hook. A tenotomy can generally be i)erformed without general anyesthesia. A drop or two of a 5 per cent, solution of cocaine produces sufficient local anajsthesia, as a rule ; and it is better, in order to be able to judge of the effect of the operation, that the patient should be fully awake. In performing tenotomy of the internal rectus of the right eye, or the external rectus of the left eye, the surgeon stands behind the patient's head. For the other lateral muscles he may stand in front at either side — preferably the left. After having inserted the speculum, a hold is taken with the fixation forceps of a piece of conjunctiva lying over the insertion of the muscle, a good quarter of an inch there- fore from the border of the cornea. A vertical snip is next made with the scissors, large enough to allow the blades to be ojjcned pretty freely underneath the conjunctiva. The scissors are then made to cut their way backwards immediately underneath the conjunctiva until they cease to encounter any resistance, and one is able to feel that their points can be freely moved about. The scissors are then withdrawn, and the hook inserted underneath the muscle. This is done by first passing it backwards along the upper or lower edge of the muscle, according to the one operated on, in such a way that its horizontal and convex portion is i)arallel with that edge. On then turning it quickly round, it slips below the muscle and is drawn forwards until it is arrested by the attachment of the tendon. It is then transferred to the left hand, and the tendon cut between the hook and the eye. After this has been done, the hook is again inserted and swept upwards and downwards, with the object of testing whether the division has been complete. If it should catch on any portion of the inser- tion which has escaped division, this portion must be divided with the scissors. A suture is then used to bring the edges of the wound in the conjunctiva together, and to prevent subsequent sinking of the caruncle, which, when it occur.s, is very unsightly. The suture should be passed diagotially doivnwards and inwards, and only take in the conjunctiva. A dee[)er suture placed hori- zontally is sometimes required if the effect of a tenotomy has been too great. The eye should afterwards be bathed occasion- ally with corrosive sul)limate lotion, but no dressing is reipiired. Operation for advancement of a rectus muscle. — A vertical incision is made with scissors in the conjiUK'tiva over the muscle to be advanced, and slightly jiosterior to the site of its tendinous insertion in the sclera. The length of this incision should be fully equal to the breadth of the muscle. Taking 552 AFFECTIONS OF THE OCULO-iMOTOIl MUSCLES. hold of its posterior lijt, a piece of conjunctiva of an approxi- mately cre.sceutic shape is then removed. The tendon of the muscle is next taken u]) on the strabisnuis hook, as in the iierformance of tenotomy. Holding the tendon forward on the hook in the left hand, the smooth branch of a pair of advancement forcejjs (Fig. 223) is passed below it. The forceps are then closed, and thus obtain a firm hold of the tendon, while the hook is at the same time withdrawn. Trans- ferring the forceps to the left hand, the tendon is divided at its insertion. Two sutures ai'e then passed through the muscle, and at the same time through the superjacent tissues (which are drawn forward by an assistant). The sutures are entered from the under surface of the muscle at some distance posterior to the i)ortion which is grasped by the advance- ment forceps. The free end of the tendon is then excised by a snip with the scissors made immediately behind the forceps. The other ends of the two sutures are next passed under the anterior j)ortion of the conjunctiva, the one on a level with the upper, the other with the lower, edge of the cornea. The two ends of each suture are now knotted together, by which proceeding the muscle is drawn forwards to- wards the cornea. The effect of this operation dejiends entirely U})on tw'O points : the firmness of the hold which the threads have of the tissues near the cornea, and the avoidance of any slipping in tying the knots. To ensure the first require- ment, the needles at the ends of the threads, which are used to carry these below the con- junctiva, should be passed deeply, traversing the FULL SIZE superficial layers of the sclera. The effective Fig 2-23.— PriuL-e's i^,jQj.tj„„ is got, on the other hand, by an advancenient for- . *= • i ,- • r- i i ceps. assistant grasping the first twist ot each knot firmly, after it has been pulled tight with a fine pair of ribbed forceps, before the second twist is made. Effect of Tenotomy and Advancement. Of the two forms of concomitant squint commonly met with, the one, as has been seen, is an active and the other a ^j)ass?'ve EFFECT OF TENOTOMY AND ADVANCEMENT. 553 condition. It is this essential dilference which accounts for the difference in the effect gained, as a rule, by tenotomy of the internus for convergent strabismus, and tenotomy of tlie cx- ternus for divergent strabismus. Tenotomy of the internus, which is actively contracted under an impulse to convergence, is followed by retraction of the muscle. It forms, in conse(juence, an adhesion to the sclera posterior to that which it formerly had, and that equally, whether the tenotomy be performed on the squinting or on the fixing eye. Tenotomy of the externus which is in a passive state (beyond the amount, which possibly varies in different cases, of its tonic innervation) is as a rule followed by little or no retraction, so that a new attachment to the sclera is formed, in the absence of any convergent power, at much the same place as that from which the separation was made. Further, the cause of the scjuint continues in both cases after operation, although the effect of the position of the eyes is altered in the first case, and not generally in the second. This being the case, the continuance or increase of convergent innervation may in the course of time lead, after an operation in which a good position has been obtained, to a return of convergent squint. Or, again, the discontinuance or diminution of convergent innerva- tion, after a similar operative result, may lead to divergence. The improvement in position at the time, however, is one which is effected for all distances of fixation. If, instead of tenotomy of one or both externi, the internus of one or both eyes be advanced, and caused to form a new attach- ment closer to the cornea (or shortened, while retaining much the same line of insertion), we get, in the absence of converging power, a new position of functional rest ; and the position thus got does not tend to be lost, unless the divergence previous to operation had not attained its full development. On the other hand, the position, though improved for distance, will not gener- ally be at the same time corrected for nearer fixation. The effect of strabismus operations is in most cases only a cosmetic one. The cases in which a more complete cure of squint is obtained are mostly those in which, with equal, or fairly equal, vision in the two eyes, the squint has developed not too early in life. Such a cure is, for instance, the all but constant result of tenotctmy for the convergent squint of myojies. It is not so very uncommon, too, in the later-developed convergent stpiint of emmetrojies and hypermetropes, especially if the scpiint has been acconq)anied by diplopia. Again, it is got by operation on divergent squints, when the vision of the deviating eye is sutticiently good on optical correction to excite fusion. 554 AFFECTIONS OF THE OCULO-MOTOK MUSCLES. It is, first, the establislunent of a more normal relation be- tween the two axes ])y a suitable operation, and second, the [trojier optical correction of the two eyes, that render binocular fixation possible. In cases, too, in which the complete cure of the squint is effected, it is got for the most part as soon as these two conditions are comitlied with. The use of stereoscopic exer- cises may possibly in some cases help. It is doubtful, however, if such exercises ever really lead to the establishment of binocular fixation where this w^ould not take place without their aid. As to operations on the lateral recti, one should be guided by the following princi})les : — As regards convergent strabismus, it is not advisable to attempt the correction of anything but the permanent or lial)itual element of the squint. Cases should not, therefore, be operated on too young, as it is generally long before an accommodative over-convergence leads to such an inveterate habit of convergence that a large portion of the excessive con- vergence persists, notwithstanding optical correction, when, as is usually the case, such correction is required. Owing to the fact that the age at which the squint first develops is not constant, and also because the habit of persistent squinting is more readily acquired in some than in others, no definite age can be fixed which is applicable to all cases. It is a good rule, and one which should only be departed from under exceptional circumstances, not to operate before the age of six. The younger the individual, too, the more careful should one be, especially in hypermetropes, not to make too full a correction by operation, but to leave some- thing to disappear in the course of time by the use of suitable glasses. This precaution is not so necessary in alternating converg- ent squint, with emmetropia and good vision in each eye, and not at all necessary in strabismus convergens mi/opicus. In the former, and even in cases otherwise similar in which the refrac- tion is hypermetropic, there is a good chance of binocular vision being resumed after operation. In the latter, this restoration of binocular vision is all but invariable. Every now and then one finds the result of a single tenotomy much greater than might be expected (the average effect is about 5 metre-angles). The cause is, then, that the retraction of the divided tendon has sufficiently reduced the over-convergence to allow fusion to do the rest that is required to render binocular vision possible. There remains, then, always more or less latent convergence, and this may, with advantage, be accurately corrected by further operation. It may even, without harm, be to some extent over-corrected. But as nearly accurate correction as is possible •NYSTAGMUS. 555 by tenotomy, and a restraining suture if necessary, sliould l)e aimed at. Periodic squints, on the other hand, should not be interfered with. In these cases optical treatment is alone called for. In the case of divergent squint, the full correction may be safely made by advancement of one or both interni in all cases in which there is no convergence left. Where there is fairly good convergence, care must be exercised, as it occasionally happens that even a tenotomy of one externus may give an over- correction. Latent divergence need only be corrected, by advancement of one or both interni, when it is considerable (5 metre-angles or over). On no account should slight latent deviations, either divergent or convergent, be touched. The fact that concomitant squint, whether convergent or divergent, is a binocular and not a uniocular defect, justifies the division over both eyes of the operative effect aimed at for its correction. It is not advisable, practically, to operate on both eyes in cases where a single tenotomy or advancement (performed first on the squinting eye) is suflicient to rectify the position. When this is not sufficient, the next step should always be to perform the similar operation on the other eye, restricting its effect, if neces- sary, by suture. In this way we avoid too great an operative insufficiency. For instance, in convergent strabismus of the right eye we may begin by tenotomy of its internus, and in- crease the effect, if necessary, by tenotomy of the left internus. This is preferable to further altering the position of the right eye by performing advancement of its externus, a proceeding which is sometimes advocated. The operations should succeed each other as follows — (1) Tenotomy of right internus, with or without restraining suture ; (2) tenotomy of left internus, with or without suture ; (3) ad- vancement of right externus ; (4) advancement of left externus. Nystagmus. Nystagmus is the name given to involuntary oscillatory move- ments of the eye. The movements are mo.stly from side to side, but may be rotatory or almost entirely vertical. They are gener- ally constant, l>ut increase in intensity with attempts at fixation, or when the individual is in any way excited. In some cases the nystagmus only exists for certain directions of fixation, most frequently when the eyes are directed upwards. There is always 55G AFFECTIONS OF THE OCULO-MOTOll MUSCLES. some degree of jerky or nystagmic movement whenever the eyes are forcibly turned in any direction, and an attempt made to maintain them for any length of time in what corresponds to the boundaries of the physiological action of the respective muscles. Nystagmus is consequently a frequent syui})tom in ocular para- lyses, Avhen the eye is moved in the direction of the weakened muscle. Most cases of nystagmus are developed in early life as the result of defective vision, at a time when the movements of the eyes suited to the recpiirenients of fixation would otherwise be acquired. The education of the co-ordinating centres is thus imperfect. Sometimes these centres appear to be primarily affected, but little is known as to the cause of this. Very early acquired nystagmus is never associated with any subjective symp- tom of the dancing of objects in front of the eyes. This is no doubt mentally suppressed, in much the same way as is the diplopia in an ordinary concomitant convergent squint developed early in life. The condition is altogether incurable. Nystagmus may be acquired in after life as the result of changes in the nerve centres, or as a consequence, it Avould seem, of some altered states of innervation, brought about by abnormal conditions of illumination and fixation. A common variety of acquired nystagmus is what is called miners' nystagmus. In this condition the irregular involuntary contractions take place mainly or entirely in looking upwards, and are associated with the subjective symptom of a correspond- ing rapid movement of external objects which is very disturbing. There can be little doubt that miners' nystagmus is caused by the tiring of the ocular muscles, which are overstrained owing to the constrained position in which the eyes have to be main- tained by the miner at his work. Later acquired nystagmus causes an unpleasant subjective symptom of external objects dancing in front of the eyes. Snell has shown very conclusively that it is only developed in those whose work is of such a nature as to necessitate the strained position of fixation. When this constant straining is given up, the nystagmus slowly passes off. In this resi)ect the miners' nystagnuis differs from that which is acquired, owing to defective vision, in early life. Muscular Asthenopia. Difficulty, more or less pronounced, in sustaining the efi"ort of seeing near objects is mainly met with in cases in which there is binocular vision. As a general rule, whenever this has been MUSCULAR ASTHENOPIA. 557 given up, asthenopic symptoms of the ordinary kind ai-o al)st'iit. This is so wliether the uniocular fixation, whicli tlien takes place, is associated with any ai)parent squint or not. Accommodation and convergence are most frecjuently botli necessary for the distinct binocular vision of near objects. Con- sequently, it would perhaps not be unnatural to assume that asthenopia might result frona weakness or exhaustion either of the ciliary muscle or of the internal recti muscles. Such an assumption, however, is found to require some modification. Accommodative asthenopia, and the somewhat similar symptoms referable to uncorrected astigmatism, have already been referred to, and their causes discussed (see }). 484). There is in the first place no sufficient evidence that weakness of the eye muscles themselves is ever the cause of symptoms of inability to sustain an eftbrt of reading or other near work. When there is any actual weakness in an eye muscle, or in its innervation, from over-strain or paralysis, we find as a conse- quence nystagmus. Possibly also the much rarer conditions of " spasm " have a similar causation. It is true, no doubt, that in many cases the irregular or nystagmic action of the weakened muscle may only assert itself for fixation in a direction corre- sponding to the limit of its action. Still it is always easy to elicit this evidence of muscular weakening. Nothing of this kind, however, is met with in the condition which is usually diagnosed as muscular asthenopia. Besides, any real muscular w^eakening necessarily leads to a loss of concomitancy in the associated movements in which it takes part. Muscular asthenopia, if the term has any justification at all, must therefore be caused by a weakening of some other kind. The well-recognised accommodative asthenopia depends, as we know, not upon any weakness of the ciliary nniscle, which is often, on the contrary, stronger than usual, l)ut on an unsuitably disposed amplitude of relative acconnnodation. In the same way there are possibly cases of asthenopia which dejjend ui)on an unsuitable disposition of the am2)litude of relative convergence. And these cases might on the same principle be referred to a category of mroscular asthenopia. At first sight it might seem that relative accommodation and relative convergence were interchangeable terms. This is not the case, however, as the starting-points of accommodation and convergence are not invariably the same. On the one hand, the state of refraction determines the starting-point of accommoda- tive effort. On the other hand, the effort of convergence is possibly related in some measure to the |ioint from which con- 558 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. vergence has to be started. In other words, it may depend upon the latent position — the position of physiological rest, which may be parallelism, more or less divergence, or even con- vergence, of the two visual axes. Nevertheless the effort to properly co-ordinate and sustain accommodation and convergence must be of much the same nature, whether the cause of an existing difficulty is primarily an unsuitable disjjosition of relative acccommodation, or of relative convergence. Theoretically, one might cxi^ect that any deviation from the ideal or emmetropic starting-point of accommodation would cause difficulties which in the long run must give rise to asthenopic .symptoms. Pi-actically, however, this is not the case. This is because the ideal relation between accommodation and convergence is, as we have seen, far from being the rule. That there is a more or less intimate relation between these two im- pulses is shown by the fact of convergent squint occurring at all. But that the relation is different in different people is evident also from the study of latent deviations. Habit, in cases of ametropia, tends to establish quite a different relation- shi]) between accommodation and convergence than that which is looked upon as ideal. It is important to bear in mind that, in connection with the association of the two eyes, one has to do mainly with the function of convergence. It is reasonable enough to suppose that asthenopia, met with in a case in which there is a high degree of latent divergence, may be ascribable to an unsuitable disposition of relative convergence. It has to be remembered, however, that asthenopic symptoms are by no means constant even in cases presenting a high degree of latent divergence. It used to be a very common thing, on the initiative of von Graefe, to operate on these cases of purely latent divergence. But in many cases, notwithstanding that a perfect operative result is obtained, no cure of the asthenopia results. Others may l)e relieved at the time, but the symptoms afterwards return without any recurrence of the latent divergence. It is therefore illogical to ascribe the temporary cure in these cases to the alteration caused by the operation. The operation may even cure by suggestion alone, and by the rest and change which it entails. Such a cure, too, may be permanent, though it is usually only temporary. This being the case in the higher degrees of latent divergence, operations are certainly unjustifiable in the slighter degrees of the same condition. MUSCULAR ASTHENOPIA. 559 It is the idea that a latent divergence or a latent convergence, however small, is an evidence of a defect in muscular balance which has led to operative interference. This same idea has given rise to the terms exophoria and exojihoria, which, however convenient they may be, are certainly less ap})roi»riate than latent diveryence and latent convergence which have for long been in use. Besides, the idea is undoubtedly an erroneous one. Anyone who is convinced of this could not or ought not, there- fore, to operate for anything but the higher degrees of deviation, which admit, at all events, of operation in a legitimate manner. The ease with which even the slightest deviations can be detected, coupled with the muscular insufficiency idea, has led to much greater importance being attached, in some quarters, to latent divergence and convergence than these conditions deserve. With regard to outward and inward deviations, it has to be remembered that the convergence innervation is of a different order, as it were, from that which governs associated movements of the eyes in the same direction. Convergence is practically mainly a reflex action : the associated movements are both reflex and voluntary. Convergence seems to be established in each individual more exclusively by fusion, — the desire for binocular vision. It thus comes to be associated more or less intimately with innervation to accommodation. Changes in refraction necessarily disturb the suitability of this association. But the association is never sufficiently close to altogether resist altera- tion. It is, consequently, mainly the more rapid refractive changes which disadvantageously disturb the relationship which fusion has established. Moreover, convergence is more or le.ss easily unlearnt. When conditions, such as uniocular l)lindne.ss or amblyopia, make binocular fixation impossible, the call for convergence is absent or weakened, fusion no longer comes into play, and eventually all efforts at convergence are given up, and it becomes impossible to elicit it in any way. But there are great individual differences in the force and continuation of the hahit of convergence. The degree of jjer- sistence of an innervation to convergence, in the absence of any necessity for converging, varies in different people. This may no doubt, to some extent, depend upon the intimacy of its established relation to accommodative impulses. The study of physiological latent deviations clearly .shows this individual difference in similar refractive conditions. All these fact.s, the experimental evidence of which has already been given, afford sufficient reasons for not ascribing any imi>ortance, a.s a rule, to such deviations. 5G0 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. There seem also to be individual differences in the strength of the fusion tendency. Certainly in some cases a weakness of fusion nuist be looked upon as ])athological. In such cases, whatever may be the cause, it is important not to ascribe the symptoms to the muscles themselves. In addition to the determination of latent deviations, there is another kind of investigation often made in connection with the movements of the eyes from which wrong inferences are very generally drawn. I refer to the determination of the limits of movement in different directions. When the examiner fails to elicit a movement in some particular direction, equal in amount to tlie supposed normal, this is often taken either as a weakness of the muscle which produces movement in that direction, or, at all events, as a defective muscular balance due to preponderating strength in its antagonist. Where there is evidence of jiaresis, as shown by a disturbance of association with the muscle or muscles which produce the same direction of movement in the other eye, this explanation is no doubt justified ; and this even where the disturbance is so slight as to be masked by fusion, and only to manifest itself latently. In the absence of paresis, however, the inference is erroneous. Attempts, too, which have often been made to measure the possible excursion with minute accuracy are hardly scientific. They often only show a failure to appreciate the essential differ- ence between the possible accuracy which may be got from a physical measurement as opposed to what can be expected from most physiological measurements. Take again convergence. How easy, is it not, for different observers, or even the same observer at different times, to elicit in any particular case varying degrees of convergence 1 There must be an effort made on the part of the patient to strain the innervation to convergence to its full amount, before relaxing it, in order to effect a maximum convergence. Much, therefore, depends upon the examiner, and the determination with which he induces this effort in his patient. Many cases, indeed, of supposed weakness or insufficiency of convergence are merely the expression of a weak innervational effort. No doubt there may often be some degree of general neurasthenia, which makes it more difficult to induce the convergence effort. A determined attempt, however, on the part of the examiner will usually readily cause the effort to be made. Such cases of weak innervational effort must not be con- founded with the much rarer cases of really weakened innerva- tion, pai"esis, or even paralysis of convergence. Are we to MUSCULAR ASTHENOPIA. 5G1 relegate all cases of weak convergence associated with asthen- opia to the category of muscular asthenopia 1 If so, is this a form of muscular asthenopia in which real and lasting benefit is to be got by operative interference 1 Here, again, if we adhere to the term muscular asthenopia, it must Vje as a con- venient expression, for what we know is not really a muscular defect, not insufficiency of the interni, but a particular form of innervational defect. It may be a more convenient term than, e.[/., non-ixiretic convergence insufficiency^ which, ho^^■ever, is certainly more appropriate. As a general rule, operations for this kind of muscular asthen- opia should not be rashly undertaken. Rest, in the shape of restricted use of the eyes for reading, etc., general tonic treat- ment, and massage is what is indicated in most cases. Abduct- ing prisms, alone or combined with convex lenses, may then l^e tried. Indeed, from the aid which may be expected from " sug- gestion " alone, as I have already hinted, it may often be useful to prescribe such glasses early in the treatment. Operation, and preferably, I think, capsular advancement of both interni, should be reserved for cases which resist this treatment. But it is absolutely essential that oi)eration should be confined to cases which present a sufficient margin of facultative absolute divei-gence to prevent the possibility of resulting convergence. There remains one other class for consideration, namely, cases of latent vertical deviation, what is now pretty generally called hyperphcjria. The asthenopia which may be associated Avith hyperphoria may also, appropriately enough, be called a muscular asthenopia. In my experience, although I invariably look for it, hyperphoria is by no means a frequent cause of asthenopia. To judge, however, from the numerous references to this form of asthenopia in American literature, it would appear to be very common. But then it must be remembered that even slight degrees of " exophoria " and " esophoria " are also taken to be the cause of asthenopia. For reasons already referred to, this must be looked upon as a mistake. Certainly slight hyper- I»lioria is often unassociated with any kind of inconvenience. On the other hand, when it amounts to only two or three degrees, or even less, binocular fixation is less easy, and in some cases an appreciable strain is put upon the regulating innerva- tion of fusion. Asthenopia .symptoms consequently result if binocular fixation is persisted in, or a manifest deviation, which from its small degree may not be very noticeable, occurs when the strain of binocular is given up for uniocular fixation, and thus asthenopia avoided. 36 562 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. There is a not uncommon association of vertical displacement with convergent strabismus. It seems probable that in some cases, ]iarticularly where there is no marked amblyopia of the squinting eye, the manifest convergent squint may actually be in a manner due to a pre-existing hyperphoria. Without the presence of this height difference, the conditions favouring over- convergence might be overcome by fusion. This would be analogous to the frequent association of an ocular jjaralysis with a latent lateral deviation. Physiologically there is comi)aratively great difficulty in over- coming vertically placed prisms in front of one eye in the in- terest of binocular vision. It is therefore natural that slight latent lateral deviations should not cause the same strain on binocular fixation as vertical deviations may do, and actually do. But there is another question to be considered. Are vertical deviations of the same nature as lateral deviations? Confusion on this point, along with the apparent similarity of causation which is suggested by the current nomenclature exo-, eso-, and hyperphoria, and the ease with which these deviations are detected, appear to me to have led to not a little misconception. If latent lateral deviations are not to be considered evidences of muscular weakness or of defective "muscular balance," are we also to exclude an origin of this kind in the case of vertical deviations 1 Latent lateral deviations we have referred to the existing in- dividual state of physiological (innervational) equilibrium in the position of the eyes which is detected in the temporary absence of binocular fixation. They are therefore expressions of a state of innervation, and vary according to the greater or less per- sistence of convergence innervation after the main controlling influence of fusion has been withdrawn. Latent lateral devia- tions are, moreover, by no means constant. They vary with the length of time during which binocular vision has, in the course of testing for them, been in abeyance. They vary also according to the particular conditions under which the eyes have been used immediately before the test is applied. Thus at first, at all events, the amount of deviation is different, if tested after a jirolonged spell of reading, from that which is found immediately after the eyes have been for long used in distant fixation. Thus there is afibrded a good scope for self-deception. The uncritical observer readily accepts any favourable change as a justification of the diagnosis of muscular defect, and of the treatment which lie may have adopted for it. But in the vertical movements of the eyes there are not, as in MUSCULAR ASTHEXOPIA. 5G3 the lateral, two differently directed innervations at play. Both ej'es move in the same direction upwards and downwards — never in opposite directions. Vertical deviations cannot there- fore be due to the persistence of an innervation which does not exist. Their cause and importance must be of a different nature from that of lateral deviations. But do these vertical devia- tions depend upon purely muscular anomalies ? There are, I think, reasons for believing that they do not. There is, for instance, no regular change in the degree of deviation on ujtward and downward fixation such as must characterise a truly muscular weakness. The movements of the two eyes are, in other words, concomitant. Then, again, it is not so very unconnuon to tind that the position of rest for each eye, on occlusion of the other, is higher than the plane in which the line of fixation lies. Whichever eye, then, is fixing, the other is rotated upwards behind the occluding hand or screen, and makes a compensatory downward movement when the obstruc- tion is removed. There are also cases in which, when one eye fixes, the other is misdirected upwards; while, when the other takes up fixation and the first is occluded, its deviation is downwards. These facts suggest another explanation for hyperphoria. And this is strengthened by the consideration of the individual differ- ences which are found to exist in the extent of latent lateral deviations for different directions of fixation. These cannot all be explained as states of innervation or habit alone. Some of them probably depend upon pecuiiarities and abnormalities in the relations of the adnexa. Similar abnormalities are, prob- ably, the cause of hyperphoria, as there is in this condition nothing characteristic of muscular defects as we know them, and no innervational cause to explain the deviation. Marked changes too, such as take place in the degree of lateral devia- tions, according to circumstances, to which reference has just been made, are not met with in vertical deviations. I'liis is another reason, if any were required, for excluding innervation, namely, the absence here of instability which is caused by changes in the state of innervation. As regards the asthenopia to whicli hyperphoria may give rise, it is evidently due to the difficulty which the relative position of rest of the two eyes interposes in the way of easy fusion. This form of asthenopia, too, is readily and permanently relieved by treatment. In this respect it re.sembles accommodative asthen- opia, and differs from the other forms of so-called muscular asthenopia which have been discussed. 5G4 AFFECTIONS OF THE OCULO-MOTOR MUSCLES. The best treatment is undoubtedly the use of vertically re- fracting prisms, which neutralise the latent angular deviation. The prisms required can be readily determined by using a Maddox rod in front of the one eye and a prism in front of the other. Generally sj)eaking, unless there are other reasons, such as anisometropia, which render it advisal)le to jdace the full strength of the vertically refracting prism in front of the one eye alone, it is best to distribute the prismatic effect as equally as possible over the two eyes. It is only rarely that an opera- tion may justifiably take the i)lace of prismatic o])tical correc- tion. It is always ditticult to get a good correction by operation. I doubt if it is ever possible to get a perfect one. But opera- tion may be tried in cases in which the hy})erphoria is very great, — more than 6° to 8°, for instance, — and also in cases where the patient, having otherwise no reason to wear glasses, is specially anxious to avoid doing so. Anything like fi'equent tampering with the muscles causing vertical rotation is certainly a mistake. In my oi>inion, too, interference of this kind should be confined to ca})sular advancement, and the primary effect of this should be an over-correction. All the forms of asthenopia, with the exception of headaches from astigmatism, may be looked upon as essentially due to some difficulty in maintaining binocular fixation at a reading distance. The existing conditions of refraction, of convergence, or, as in hyperphoria, of the relative positions of rest of the two eyes, may be the cause of this difficulty. A greater than normal eftbrt may thus devolve upon the fusion innervation. But it is evident that the effort of fusion may be greater than can easily be made even in the absence of any abnormalities in these con- ditions, merely, it may be, owing to general neurasthenia. The synn)toms are then the same. This neurasthenic element should always be kept in view. Otherwise too great importance may be attached to slight devia- tions from the ideal normal conditions, which in reality have little or no bearing on the asthenopia. More especially should we guard against attributing any etiological importance to the muscles themselves, as the term "muscular asthenopia" is apt to suggest. These considerations should lead us to avoid, as a general rule, operations on the muscles for asthenopia ; but the very real troubles which constitute asthenopia need not be neglectecl. On the contrary, they call for treatment. The accommodative form and that due to hyperphoria can be i)ermanently, though it may be not always immediately, relieved by convex lenses MUSCULAR ASTHENOPIA. r,G5 in the one case and prisms in the other. In otlier forms too, glasses (which may often advantageously be tinted), rest, graduated use of the eyes, and suggestion other than by opera- tion, will usually help to modify, if not altogether to remove, the asthenopia. INDEX. Abscess of the lid, 71. Accommodation, 455. amplitude of, 446. diphtheritic paresis of, 489. paralysis of, 489. relative amplitude of, 538. spasm of, 491. Accommodative asthenopia, 538. After-cataracts, 196. operation for, 224. Albinism, 303. Amaurosis, 412. Amblyopia, 412. central toxic, 415. from disixse, 539. reflex and hysterical, 421. from tobacco, 418. Anajmia of the retina, 237. Anchyloblepharon, 73. Aniridia, 302. Anterior chamber, 305. Antiseptics in eye operations, 6. Arcus senilis, 172. Arterial pulsation, 235. Asthenopia, accommodative, 451. muscular, 566. nervous, 21. Astigmatic fan, Snellen's, 476. Astigmatism, 472. headaches due to, 483. irregular, 484. lenticular, 481. regular, 472. Atrophic excavation, 269. Atrophy of optic nerve, 269. primary, 269. secondary, 269. Balance, Priestley Smith's, 3. Bjerrum's screen test, 20, 270, Blepharitis, 44. Blepharophimosis, 73. Blepharospasm, 71, 115. Buller's shield, 168. Canaliculi, 43. slitting the, 81. Canthoplasty, 119. Capsule forceps, 215. Cataract, 190, after-cataract, 196. anterior capsular, 138. black, 192. capsular, 190, 194, 202. complicated, 191, congenital, 199, diabetic, 195. extraction, 208, 210. by suction, 209. without iridectomy, 220. glass-blowers', 207, juvenile, 191, 'lamellar, 199. lenticular, 190. Morgagnian, 192. nuclear, 191. operations for, 201, pyramidal, 138. secondary, 191, 202. stationary, partial, 202. traumatic, 191, 203, 297. Catarrhal ulcers, 97. Cautery, thermo-, 149, 219. galvano-, 150. Chalazion, 52, Chalky infarcts, 54. Chancres of the lids, 72. Chlorine water, 219. Choked disc, 265. Choroid, 41, 307, coloboma of, 327, hremorrhages in, 330. ossification of, 330. rupture of, 325. INDEX. 567 Choroi d — continued. tubercle of, 328. veins of, 42. Choroidal ring, 40. Choroiditis, 308. disseminated, 308. metastatic purulent, 323. purulent, 322. senile central, 314. sj'philitic, 316. traumatic jiurulent, 323. Circumcorneal injection, 275. Clouded vision, 26. Cocaine, 5. Colobonia lentis, 232. Colour blindness, 429. Conical cornea, 172. Conjunctiva, adenoid hyperplasia of, 91. amyloid degeneration of, 128. chancres of, 135. dermoid cysts of, 134. ecchymosis of, 128. emphysema of, 128. epithelioma of, 134. essential shrinking of, 128. foreign bodies in, 131. hj'])er;eniia of, 91. injuries to, 131. lymphangiectasis of, 133, normal, 90. rodent ulcer of, 134. sarcoma of, 135. Conjunctivitis, 93. catarrhal, 96. diphtheritic, 122. follicular, 102. gonorrh(eal, 104. granular, 123. lij'lierplastic, 103. membianous, 112. Ijjdyctenular, 113. purulent, 104. pustular, 114. treatment of, 98. Convergence, 10, 496. Cornea, clear ulcers of, 162. congenital malformations of, 175. deposits in, 180. dermoid cyst of, 174. iibroma of, 175. fistula of, 138. hypopyon ulcer of, 160. injuries to, 176. malignant tumours of, 175. Cornea — continued. marginal ring-shaped ulcer of, 163. Mooren's rodent ulcer of, 163. nebula of, 137. tattooing of the, 183. transverse calcareous film of, 170. Corneal microscojie, 10, 28. spud, 179. Correctopia, 302. Corrosive sublimate for operations, 6. Cyclitis, 296. Cystoid cicatrix, 228. Dal'uydcystitis, 82. acute purulent, 82. Uacryops, 79. Dermoid cysts of conjunctiva, 134. of lid, 71. Descemetitis, 291. Desmarres' retractor, 9. Diplopia, 22, 515. Disc, optic, 36. Discission for cataract, 207. Dislocation of lens, 229. idiopathic, 229. into anterior chamber, 229. into vitreous, 229. subconjunctival, 229, 231. traumatic, 229. Drum testing, 2. Ectopia lentis, 232. Ectropion, 61. cicatricial, 64. conjunctival, 61. Snellen's operation for, 62. Electric light o]ihthalniia, 133. Embolism in retinal arteries, 253. Encejilialocele, 402. Entropion, 54. cicatricial, 57. senile, 56. spasmodic, 55. Enucleation, 355. Epicanthus, 68. Episcleritis, 184. Erythropsia, 425. Evisceration, 355. Examination of the eve, methods of, 8. Excavation of disc, physiological, 40. r)6S INDEX. FoiiKlON bodies in the anterior chamber, 336. iris, 337. lens, 340. posterior aqneous chamber, 337. posterior se('tion of the eye, 342. Fovea, 34. Fundus, normal, 32. Glaucoma, 360. aniosthesia of the cornea in, 370. Bjerrum's symptom of, 370. cataract witli, 377. fulminans, 368. hii^morrhagic, 376. iridectomy lor, 378. malignant, 379, 384. myopia with, 377. prognosis in, 377. restriction of the field of vision in, 368. secondary, 375. simple, 372. (ilioma of the retina, 390. Granuloma of the iris, 295. Graves' disease, 408. H^MOPJiHAGES, retinal, 237. Hemianopia, 432. bi-temporal, 434. homonymous, 433. Herpes zoster frontalis, 50. Heterochromia iridis, 304. Hordeolum, 48. Hyperaemia of the retina, 236. Hypermetropia, 462. index, 464. Hyphfema, 306. Hypopyon, 278, 306. Intra-ocular tension, Iodoform, 6. Iridectomy, 286. Irideremia, 302. Irido-dialysis, 300. Iridotomy, 225. scissors, 226. Iris, 274. atrophy of, 301. bombe, 281. coloboma of, 301. forceps, 210. hook, 210. hyperaemia of, 275. injuries to the, 300. 10. Iris — continurd. prolapse' of, 224. scissors, 211. tumours of, 298. Iritis, 224, 275. gonorrha-al, 287. gummatous, 289. recurrent, 279. rhenmati(!, 287. serous, 291. syphilitic, 288. trauTuatic, 294. tuberculous, 295. Jamieson's files, 127. Javal's ophthalmometer, 477. Keratitis, 136. dendriform, 161. fascicular, 155. hypopyon, 159. interstitial, 167. nenro-paralytic, 170. phlyctenular, 154. recurrent bullous, 164. sclerotising, 188. secondary, 165. vesicular, 164. Koch-Weeks bacilli, 94. Knai)p's roller forceps, 127. Kuhnt'scanthoplastic operation, 120. Lachrymal gland, adenoma of, 77. fistula of, 78. hypertrophy of, 77. infiammation of, 77. malignant tumours of, 79. Latent positions, 503. Lens, growth of, 189. Lenticonus, 233. Leucoma, 137. adherens, 139. Light sense, 13. Macrocornea, 175. Macrophthalraos, 175. Macropsia, 24. Maddox's glass rod, 500. Meibomian glands, 44. Metamorphopsia, 24, 258, 312, 318. Microcornea, 175. Microphthalmos, 175. Micropsia, 24. Microscope, corneal, 10. Milium, 51. INDEX. 569 Molluscum contagiosuni, 49. Morax bacilli, 95. Muscfc volitantes, 26, 128. Myopia, 465. school, 468. N.EVI of the lids, 72. Neuritis, retrobulbar, 267, 4] 7. Neuro-retiuitis, 263. , Nictitatio, 70. j Night blindness, idioiiathic, 426. of retinitis pigmentosa, 250. Noma, 71. Oi">i,ii,>UE illumination, 27. Ocular muscles, jiaralysis of, 515. Qidema of the lids, 71. Opaque nerve fibres in tlie retina, 261 . Ophthalmia neonatorum, 104, 110. tarsi, 44. Optic nerve, tumours of the, 401. neuritis, 263. Orbit, aneurysm of the, 403. foreign bodies in, 407. gumma of, 396. malignant tumours of, 400. tumours of, 398. bony wall, 399. connective tissue, 400. Orbital cellulitis, 395. periostitis, 395. Pagenstecheu's ointment, 116. spoon, 219. Panuus, 157. crassus, 157. strumous, 158. trachomatous, 124, 158. Panophthalmitis, 322. 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