5211 FUNCTIONAL NEEV0U8 DISEASES THEIE CAUSES AND THEIE TREATMENT MEMOIR FOR THE CONCOURSE OF 1881-18S3 acad:^mie ROY ale de M^DEGINE de belgique WITH A SUPPLEMENT ON THE ANOMALIES OF REFRACTION AND ACCOMMODATION OF THE EYE AND OF THE OCULAR MUSCLES BY GEOEGE T. STEVENS, M. D., Ph. D. MEMBER OF THE AMERICAN MEDICAL ASSOCIATION, OF THE AMERICAN OPHTHAL- MOLOGICAI, SOCIETY ; FORMERLY PROFESSOR OF OPHTHALMOLOGY AND PHYSIOLOGY IN THE ALBANY MEDICAL COLLEGE Traditionem pondero, doctrinam resplcio, sequor veritatem NEW YORK D. APPLETON AND COMPANY 1887 COPTRIGHT, 1S8T, By D. APPLETON AND COMPANY. loo TO Db. E. LAXDOLT, OF PAEI9, ■WHOSE MAXT VALUABLE C0XTE1BUTI0N9, TO THE SUBJECTS OF MUSCULAR AND OF EEFEACTIVE ANOMALIES OF THE EYES, HAVE ENEICHED THE LITEEATUBE OF OPHTHALMOLOGY, THIS VOLUME 13 INSCEIBED, AS A TOKEN OF HIGHEST ESTEEM AND OF SINCEBE FEIENDSHIP, BY THE AUTHOE. PREFACE. This memoir, which received, from 1' Academic Royale de Medecine of Belgium, the highest honor awarded for the competition of 1881-1883, is now pre- sented in the English as it was then in the French lan- guage. The thesis for the concourse was, ";6lucider par des faits cliniques et au besoin par des experiences la pathogenic et la therapeutique des maladies des centres nerveux et principalement de I'epilepsie." Since this memoir was received by the Royal Academy, in December, 1883, many new views and experiences have presented themselves to the author, which he would have gladly included in this edition of the work. This would have been inconsistent with the plan of giving it substantially in all particulars as it was submitted to the distinguished body which had al- ready passed judgment upon it. It has been thought best to shorten the work in certain measure, and in vi PREFACE. the revision thus made necessary the original form has been retained in every particular as far as possi- ble, and while in a few instances such revisions have been made as were rendered necessary by the haste in which the original manuscript was prepared, the views and methods maintained in the original have been strictly preserved, without modification. In order to introduce reproductions from photo- graphs of some typical cases of neuroses in which the striking changes of physiognomy resulting from a relief to the tension of the eye-muscles in such cases is shown, the histories of these cases have been introduced. These histories, not in the original mem- oir, and obtained since its presentation to the Eoyal Academy, are indicated by brackets [ ], which in each instance permit them to be recognized as new ma- terial. By an unfortunate occurrence, all the negatives from which these photograveurs were to have been made were destroyed by fire while the work was being executed. It then became necessary to re- produce the portraits from very indifferent prints. Under these discouraging circumstances the result, although quite different from what was at first hoped, has been much better than might have been expected. The supplemental portion of the work has been added, not for the expert in ophthalmology, but for PREFACE. vii tlie general practitioner who would like to make suck examinations of ocular conditions as will enable him intelligently to advise and to treat his patients af- fected with nerv'ous complaints. That part of the supplement devoted to refraction and accommodation is made as comprehensive as possible consistent with brevity. In the treatment of muscular anomalies, much that is not to be found in the text-books on the affections of the eye is given. The subject has, in text-books, received but meager attention, quite insufficient to afford valuable assistance to one who would attempt the treatment of nervous complaints by removal of muscular defects. While the subject is treated here only in outline, it is hoped that the student of this subject will find here a better guide than has been elsewhere offered. The author is indebted to the publishers for the skill with which the difficulties attending the repro- duction of the portraits were overcome, and for the excellent manner in which they have presented the work. 33 "West Thiety-thied Steekt, New Yoek, May, 1887. COI^TEN"TS. PAGE Inteoductton 5-11 Statement of Principles 13-35 Division of Nervous Affections into Functional and Organic 13 Immediate and Predisposing Causes 14 Neuropathic Predisposition 15 Hereditary Tendency 16 Modifying Tendencies 17 Reflex Irritations 19 General Proposition 21 The Eye as an Irritating Cause 23 Theory of the Adjustments of the Eyes .... 22-30 Practical Illustrations 31-35 Cephalalgia, or Headache 35-50 General Symptoms 35-37 Attendant Symptoms not Causative 37 Nervous Symptoms Interchangeable 39 Illustrative Cases 40, 41 General Results of Treatment 47-50 Migraine, or Sick-Headache 50-60 Symptoms 50 Etiology 53 Influence of Ocular Defects 53 Illustrative Cases .......... 54r-60 Neuralgia GO-81 Definition 61 General Characteristics 61 Points Douloureux 63 Migraine Interchangeable with other Neuroses ... 65 Neuralgia no Pathology 65 Immediate Causes 66 Predisposing Causes 67 X CONTENTS. PAGE Influence of Ocular Anomalies in causing Neuralgia . . 68 Results from Eelief of Ocular Conditions .... 69 Illustrative Cases 70-76 General Propositions respecting Neuralgia .... 76 Table showing Neuralgic and Ocular Conditions ... 77 Summary of Table . 78 Question of Heredity in Neuralgia 80 Spinal Irritation and Neurasthenia 81-87 Nearly Allied Forms of Neuroses 81 Mimoses 82 Pathology of Spinal Irritation not demonstrated ... 83 Influence of Neuropathic Predisposition in Neurasthenia . 83 Illustrative Cases 83-87 Chorea 87-101 Bearing of some Characteristic Features on its Etiology and Treatment 87 Chorea among Hyperopic Children 89 Dilatation of the Pupils in Chorea 90 Proportion of Ocular Anomalies in Cases of Chorea . . 91 Statements of Cure in Cases of Acute Chorea of Little Value 92 Results of Treatment in Chronic Cases Significant . . 93 Illustrative Cases 93-100 Indications for Treatment of Chorea 101 Epilepsy 101-120 No Pathology in Idiopathic Epilepsy 102 Existing Doctrines respecting the Etiology Unsatisfactory . 102 Heredity as Predisposing Cause 102 Nature of the Hereditary Tendency 103 Ocular Conditions in Epilepsy 104 Results of Treatment of Ocular Defects in Epilepsy . . 106 Illustrative Cases 107-120 Mental Disorders 120-124 Recovery upon Relief of Ocular Conditions .... 121 Illustrative Cases 121-124 Conditions of Eyes to be examined in Mental Disorders . 124 Heredity 124-131 Construction of the Eyes constitutes an Important Element in Heredity . 124 The Eyes as a Part of the Facial Features .... 125 Excessive Demands upon the Nervous Energies from Diffi- cult Adjustment of the Eyes 126 Similar Irritations do not always react in the Same Manner 126 Supposed Increase of Nervous Disorders in Modern Thnes . 127 History of Diseases in Neurotic Families .... 127 CONTENTS. xi PAGE Study of the Record of Diseases in Families with High Re- fractive Errors 131 The Treatment of Nervous Diseases 131-138 Ocular Conditions should occupy a Prominent Place . . 131 Medicines have a Certain Value 131 Certain Familiar Principles 132 Spontaneous Cures 132 Prisms for Gymnastic Exercise 133 Insufficiency of the Externi 134 Operations for Relief of Insufficiency of External Recti . 135 Method of Operation 136 Employment of Extract of Calabar Bean .... 137 Employment of Atropia . 138 Prevalence of Refractive Errors among School-Children . 138 Dangers of Xeglect of Such Conditions 138 Table coxtaixixg Records of Diseases ix Families with Marked Refractive Errors 139-147 Summary of above Table 146 SUPPLEMENT. Knowledge of Refraction and Muscular Anomalies Essential to the Successful Treatment of Nervous Complaints . 148 Refractiox and the Accommodation op the Eye . . . 149-156 The Eye as an Optical Instniment 149 Dioptric System 149 Construction of the Ideally Normal Eye .... 149 Theory of Accommodation 151 Range of Accommodation 155 Refraction of the Eye . , 156-157 Emmetropic Eye 156 Hypermetropic Eye 156 Myopic and Astigmatic Eye 157 Hyperopia, or Far-Sight 157-160 Depends on the Form of the Eye 157 Accommodative Asthenopia 153 Symptoms and Results of Hyperopia due to Fatigue of Ac- commodation 158 Symptoms of Accommodative Asthenopia .... 159 Latent and Manifest Hyperopia 159 Myopia, or Near-Sight 160-165 Myopia dependent on the Anatomical Formation of the Eye 160 xii CONTENTS. PAGE Popular Errors in regard to Near-Sight .... 161 Myopia Progressive 163 Pathological Conditions in Myopia 163 Spasm of Accommodation 163 Myopia prevalent among the Educated Classes . . . 164 Relations of the Ocular Muscles an Important Predisposing Cause 165 Astigmatism 165-167 Nature of Astigmatism 165 Hyperopic Astigmatism 166 Myopic Astigmatism 166 Compound Astigmatism 167 Mixed Astigmatism 167 General Effects of Astigmatism 167 Examination and Treatment of Ametropia — Test-Types . 168-183 Principle for the Construction of Test-Types . . . 168 Testing Acuteness of Vision 168 Test-Types for Near Vision 168 Snellen's Test-Types 169 Dioptric System . . 170 The Ophthalmoscope in the Diagnosis of Ametropia . . 171 The Author's Case of Trial-Lenses 173 Method of ascertaining the Refractive Condition of the Eye 173 Tests for Astigmatism 178 Glasses for Correction of Astigmatism 180 Formulae for Correcting-Lenses 181 Unequal Refraction of the Eyes (Anisometropia) . . 183 Treatment of Presbyopia 183 Presbyopia not due to Flattening of the Eyeball . . . 183 Determining the Degree of Presbyopia 183 Donder's Table for Presbyopia 184 Complications of Presbyopia 184 Subjects of Interest relating to Refraction and Accom- modation 186 A Few Pojjular Errors 186 Colored Glasses 187 Pebbles 187 Frames for Eye-Glasses and Spectacles . . . . . 187 Prejudice against Employment of Glasses for Presbyopia . 188 Affections of the Ocular Muscles in which Binocular Vision may be maintained 188-317 Complicated Systems of Muscles co-operating in Binocular Vision ' . • 188 Nature of Binocular Vision 189 CONTENTS. xiii PAGE Division of Affectioxs of Ocular Muscles into Two Great Classes 189 Subdivision of one of these Classes 190 Strabismus 190 Insufficiencies of the Ocular Muscles 190 New System of Terms 190 Heterophoria 191 Teachings of Graefe and others in this Department . . 191 Orthophoria 192 Esophoria, Exophoria, and Hyperphoria .... 193 Hyperesophoria and Hyperesophoria 193 Methods of recording Heterophoria 193 Method of examining the Condition of Ocular Muscles . 193 Graefe's Test for Insufficiency of the Interni . . . 198 Standard of Abduction 198 Sursumduction 199 Standard of Adduction 199 Hyperphoria 200-203 Definition 200 Difference between Hyperphoria and Strabismus . . . 200 Importance of Hyperphoria 200 Complications arising from Hyperphoria .... 201 General Symptoms arising from Hyperphoria . . , 201 Attitudes and Facial Expression in Hyperphoria . . . 203 Vision in this Condition 203 Abnormal Secretion of Tears resulting from Hyperphoria . 203 Eeflex Results 203 Treatment of Hyperphoria 208-206 Highest Skill of the Surgeon demanded .... 203 Method of performing Tenotomy of Eye-Muscles . . 203 EsoPHORiA 204-208 Slight Attention in the Literature of Ophthalmology given to this Condition 204-206 Symptoms resulting from Esophoria 207 Method of determining Esophoria 208 Treatment of Esophoria 210 Exophoria 210-214 Exophoria and Insufficiency of the Interni .... 210 Method of discovering Exophoria 211 General Symptoms from Exophoria 211 Exophoria and Myopia 213 Adducting Power 213 Treatment of Esophoria 214-217 lE^TEODUCTIOIsr.* Paitts spreading to parts contiguous to tlie eyes, as the result of strain to those organs, in much the same manner as pain from a wound extends to the environ- ing tissues, have long been observed. In many of the older treatises on the diseases of the eye, headaches, nausea, and vertigo are mentioned as parts of that group of symptoms which we now designate as as- thenopia. It is to be remembered that the phenomena of ac- commodative asthenopia, while recognized, were, until its nature and causes were more fully explained by Bonders in his remarkable work published in 1864, described under different names, such as Tiebetudo visus, amblyopie presbytique, etc., and were by many supposed to possess a distinct pathology, such as hy- persemia of the retina, or an increase of some of the humors within the eye. There was a general agree- ment, however, in the grouping of the phenomena and in regarding excessive or disadvantageous use of the eyes themselves as the exciting cause. The groujDing consisted, as it now consists, of pain, tension in the * Submitted to the Eoyal Academy of Medicine, July, 1886. 6 INTRODUCTION. forehead, dazzling and confusion of vision, inability to continue the use of the eyes, to which by many authors were added the more general sensations of dizziness, nausea, headaches in other parts of the head than the forehead, and general malaise. Antoine Maltre-Jan* (1707) gives a good descrip- tion of the complaint, which he thinks arises from in- creased intra-ocular tension resulting from strain of the eyes. A century later, Weller f (1832) enumerates tension over the eyes, headaches, nausea, and vertigo, to which train of phenomena Sichel % (1837) adds in- somnia, as the group of symptoms arising from ex- cessive use of the eyes. An old author, * in speaking of the people who require glasses for reading, but neglect to use them, remarks facetiously, "Their eyes ache, their head aches, and every bit of 'em aches." Piorry^ (1850) quotes from his writings twenty years earlier, his views regarding certain nervous disturbances, '■'■oscil- lations nerveuses'''' having their seat in the eye, the ear or in some branches of the fifth nerve. A form of migraine which he calls ^Hrisalgie''^ has, according to him, its origin in irritation arising either from the iris or from the retina. The migraine results in such cases from excessive or improper use of the eyes. He cites the case of a medical professor who * " Traits des Maladies de I'CEeil," 1707, p. 2G0. t " Maladies des Yeux, traduite par Kiester," Paris, 1832, tome ii, p. 215. X " Trait6 de rOpLthalmie," etc., Paris, 1837. * Dr. William KitcLner, " Economy of the Eyes," 1824. ^ Piorry (1850), "Traite de Medecine pratique," tome vii. INTRODUCTION. 7 habitually suffered from migraine after reading his lectures written in very fine characters, and who was free from the affection when he did not read the lect- ures. He also mentions the case of another physi- cian who suffered severely from the same affection uniformly after several attempts to use glasses not adapted to his eyes. Piorry made no practical appli- cation of these views. These few examples will serve to illustrate the ex- tent to which the eyes were supposed to affect con- tiguous or more remote parts, up to the era when, by the discovery of the ophthalmoscope by Helmholtz, by the recognition of the role played by the ocular mus- cles in inducing fatigue about the eyes, a subject espe- cially elucidated by Von Graefe, and by the discovery of hypermetropia by Donders, the knowledge of the causes and treatment of asthenopia was infinitely pro- moted. Notwithstanding these great advances, the phe- nomena of asthenopia continued to be stated in much the same order as before. Graefe and Donders enumerate the symptoms sub- stantially as they are given above, and Stellwag* concludes his excellent description of accommodative asthenopia as follows : "If the work is continued" (after the sense of ex- haustion has commenced), "these feelings" (confusion of vision and swimming of objects before the eyes, with a feeling of pressure, fullness, and tension in the forehead) " soon increase to actual pain in and over * Stellwag, first American edition, 1868, p. 622. 8 INTRODUCTION. the eyes and are soon accompanied by a very painful feeling of dazzling ; finally headache, dizziness, uni- versal malaise, and even nausea occur." Beyond question, however, the most important recognition of the fact that distant pain might be induced by straining the eyes was by Anstie,* who as- serted that "functional abuse of the eyes" is a power- ful source of irritation tending to induce neuralgia. He also says that hyperopic sewing-girls are spe- cially liable to that affection, and relates that he him- self was relieved from neuralgia by desisting from the use of his eyes in reading. I^otwithstanding these assertions, Anstie seems to have made no practical application of the important facts thus enunciated, and even seems to regard the conditions as accidental and factitious. Possibly a greater familiarity with the defects which are known to be influential in the jDroduction of asthenopia would have encouraged this learned author to make some practical application of a principle which he seems to have very imperfectly recognized. Thus far, then, there had been recognized certain isolated facts concerning irritations arising from disad- vantageous use of the eyes, in relation to parts some- what removed from them. No general principle of sympathetic or reflex irri- tation had, however, been formulated,, and the first printed announcements of the existence of such a principle was made by myself, in a paper presented to the Albany Institute in the early part of 1876, and * " Neuralgia," D. Appleton & Co., New York, 1872. INTRODUCTION. 9 soon after in a paper read before the Academy of Medicine in New York, June 15tli of the same year. The doctrine had, however, been publicly taught by me in lectures in the Albany Medical College two years previously to the reading of these papers, and several cases in which chorea and other nervous diseases were in relations of effects of ocular disturbances had been exhibited to my classes. Several papers relating to this subject have been given to the public by myself from time to time in which the doctrine has been somewhat more fully developed.* A few writers have, since my first publications on this subject, recognized certain facts relating to it, but it can not be said that any contribution of considerable importance has been added to the literature beyond what has been stated. If it is remembered that pain over the eyes, and even general headache, with feelings of general malaise, have been long recognized as among the occasional ♦ See " Transactions of the Albany Institnte, 1874-1876 " ; " Chorea," " Transactions of the New York Academy of Medicine," 1876 ; " Refrac- tive Lesions and Functional Nervous Diseases," "New York Medical Record," September, 1876 ; " Light in its Relation to Disease," " New York Medical Journal," June, 1877; " Clinical Notes of Cases of Neu- ralgia and Troubles of the Accommodation of the Eye," "New York Medical Record," October, 1877 ; " Relations between Corneal Diseases and Refractive Lesions of the Eye," International Medical Congress, Philadelphia, 1877 ; " Enucleation of an Eyeball, followed by Immediate Relief in a Case of Diabetes Insipidus," " Transactions of the American Ophthalmological Society," 1878 ; " Two Cases of Enucleation of the Eyeball," " Alienist and Neurologist," January, 1880 ; " Ocular Muscular Defects and Nervous Troubles," "Transactions of the New York State Medical Society, 1880; " Oculo-Neural Reflex Irritation," International Medical Congress, London, 1881 ; etc. 10 INTRODUCTION. symptoms of astlienopia, it will be understood that, in the treatment of their asthenopia patients, oculists have from time to time casually relieved these more general symptoms while pursuing the rational measures of treatment for asthenopia. Such relief, incidental so far as the design in treatment was concerned, did not, in the minds of oculists suggest the principle that for such general symptoms not attendant upon asthenopia, the condition of the eyes should be examined, and per- haps treated. Thus, while Graefe recognized headache as one of the occasional symptoms of asthenopia, he did not suggest that persons subject to chronic cephalalgia should consult an oculist. If the doctrines taught in the following pages should be accepted by the medical profession, doubt- less many oculists might be able to recall relief to headaches as incidental to treatment of asthenopia. It would not be surprising even if the recollection of such an occurrence should induce in the mind of the practitioner the belief that he was then acting upon the principle here developed, A careful and extensive search in the literature of ophthalmology and of general medicine has not en- abled the writer to find any mention of the principle that irritations arising from ocular adjustments may act as reflex causes, inducing nervous troubles in dis- tant parts, except in the vague manner already men- tioned, prior to his own announcement of it. Should the facts presented in this memoir appear to differ so essentially from the experience of medical practitioners generally as to seem to belong to the INTRODUCTION. H marvelous, it can be said that they are all capable of being fully substantiated. The author refers with pleasure to the several well- known medical gentlemen whose names appear in con- nection with some of the most typical cases here reported. He is sure that in every instance these physicians will affirm that these cases have been not only not exaggerated, but in every instance under- stated. Surely we are not to hope for a specific against all neuroses. Our greatest advance must be in the recog- nition of some new classes of causative influences, and the means of combating those influences. If the author has presented to his profession one such new class of influences which shall be found of signal im- portance, his purpose will have been fully accom- plished. FUNCTIONAL NERVOUS AFFECTIONS. In the study of nervous affections, the division of such disorders into functional and organic has long been recognized ; and while these groups touch and mingle, so that no accurate boundary can be drawn between them, the division is nevertheless practical and necessary. In the first group is found an extensive array of disturbances, characterized by diminution or increase of sensory or of motile power, or by a variety of other phenomena in which we find no evidence of an organic change, either of the nerve affected or of any portion of the central nervous system. In the second group, distinct anatomical lesions are found, which may account for some or all of the peculiar manifestations. There are certain obvious advantages in the study of the etiology of the first group. In case of struct- ural degeneration of a portion of the nervous organiza- tion, should the true cause of the disturbance be found and removed, the degenerated structure may not re- 14 FUNCTIONAL NERVOUS AFFECTIONS. sume its normal function or physical condition, and the symptoms may continue. On the other hand, if, in case of functional nervous disorder, the cause be removed, a reasonable hope may be entertained that the normal state may be resumed ; and if the removal of a hypothetical cause is system- atically followed by a cessation of the nervous dis- turbances, we have evidence of value that the hypo- thetical is the actual cause. Two classes of influences are recognized as causes of functional nervous disorders, the more remote or predisposing causes and those which are immediate. The former, while frequently of insufficient intensity to originate neuroses, may, when the nervous disturb- ance has been once instituted, be sufficient to x^erpetu- ate it for an indefinite time. Immediate causes are perhai')S rarely of a nature to induce long-continued nervous disorder, and in many instances, in which an occasion of disturbance may seem to be clearly indi- cated by the history of the affection, the influence of the supposed cause may long have passed away, while a pre-existing cause may be continuing the disorder. This fact can not be too clearly recognized in the study of this class of affections. It may, for instance, be of little practical impor- tance that a child first manifested symptoms of chorea while under the influence of fright. The evil has been accomplished, and the event can not be recalled, nor can such an influence be regarded as permanent or of long continuance. Hence, if the child continues to manifest the symptoms of chorea, it is reasonable to NEUEOPATHIC PREDISPOSITION. 15 search for an underlying cause whicli is permanent or continuous. Otherwise, it would be necessary to as- sume that, as a result of the immediate cause, some radical disarrangement of nervous action originated which perx^etuates itself. ^uch radical disarrangement has not been demon- strated, nor is its existence at all probable. The hy- pothesis, therefore, that there is an underlying cause of disturbance becomes stronger in proportion as the idea of a radical disarrangement is surrendered. Such underlying causes are fully recognized by students of nervous disorders, and their existence is so constantly verified by the daily experience of medical observers that their importance can not be questioned. Persons in whom such underlying causes exist are said to possess a neurojpatMo jpredlspositlon^ and indi- viduals subject to this unfortunate predisposition are liable, from trifling immediate causes, to suffer from neuroses which manifest themselves in a great variety of ways. Thus, one individual will, as a sequel to almost every unusual emotional or intellectual excite- ment or depression, suffer from headache ; another will, with atmospheric changes so slight as to be little regarded by most persons, habitually "take cold." One result of the many careful observations which have been made respecting this neuropathic predis- position has been to demonstrate that in a very large proportion of instances it is hereditary ; but that the hereditary tendency does not necessarily transmit the identical form of neurosis, and that any one or more of a variety of kindred affections may arise as the 16 FUNCTIONAL NERVOUS AFFECTIONS. result of the tendency. This important principle is illustrated in innumerable instances in which individ- uals suffering from a special form of nervous disease are able to trace the same or some quite different form of nervous trouble in parents or relatives. Thus, in one habitually subject to neuralgia, a family tendency may be found to various neuroses, such as chorea, epilepsy, oft-recurring nervous headaches, or possibly insanity. Anstie, who has made special and extensive inquiry respecting this tendency, finds that neuralgia, insani- ty, epilepsy, paralysis, chorea, a tendency to uncon- trollable alcoholic excesses, and phthisis are among the group of disorders which, through hereditary tend- ency, may manifest themselves either in the same manner or interchangeably. The nature of such predisposition has not been rec- ognized to an extent equal to its importance, and it will be one of the objects of this essay to point out a physiological group of circumstances which, beyond a doubt, constitutes a most important factor in this tendency. The great value of the knowledge of this factor in the predisposing tendency will appear when it is stated that this group of physiological circum- stances is capable of such modification as to render it in most instances comparatively harmless. Of immediate causes of neuroses, there is so great a variety that any attempt at an enumeration would be futile. Among the more frequent and important, however, may be mentioned the depressed conditions of the nervous system after recovery from exanthem- MODIFYING TENDENCIES. 17 atous diseases, severe and long-continued mental or physical strain, excessive emotional excitements, phys- ical shock, and sudden and extreme changes of tem- perature. The effect of these and many other exciting causes must, in the nature of the case, be transitory, and, independently of some more permanent influence, can rarely if ever account for long-continued and especial- ly for intermitting forms of nervous diseases. Another class of causes should be recognized as exerting marked influence in nervous disorders. These may be designated '-'• modifying tendencies.'''' Among these may be mentioned the influence of vitiated atmosphere — the so-called malaria ; the period of life ; the performance of certain physiological func- tions, especially those peculiar to females; and the nature of the employment of the individual. Thus, one subject to recurring headaches, while residing in a malarial region, may find the paroxysms so modi- fied as to resemble attacks of malarial fever. The period of recurrence of migraine or of ordinary head- aches is in a considerable number of females governed by the recurrence of certain physiological periods. It must be evident that, whatever may be the ex- citing cause of a neurosis, it must, under the great majority of circumstances, be of infinitely less conse- quence than the influence which leads to it and per- petuates it. The predisposing influence not only tends to pro- long the disorder, but in a vast number of instances, when a certain form of disorder is supposed to be 18 FUNCTIONAL NERVOUS AFFECTIONS. cured, individuals subject to the neuropathic predis- position will become the victims of some other nerv- ous disease. Individuals affected by one form of nervo'us disorder at one period of life are especially- liable to suffer from some other form at another pe- riod. Thus, chorea in most instances runs its course in the space of a few weeks, but the person who has been a victim of this affection in early life will be likely to suffer from neuralgia or headaches, and some- times from epilepsy, in later years. Hence, the pre- disposition is one which is a constant element in the organization of the individual, and may be the same for different forms of disorders ; and, moreover, the cure of one complaint may be only the signal for the commencement of another ; or, more correctly, the supposed cure of one form of disorder may be only a change in the manner of manifesting a permanent irritation. These principles being accepted, it is important to inquire whether such a predisposing cause must be general, pervading the whole organism, thus affecting the whole nervous system; or must it at least neces- sarily find its seat in the nervous centers ; or may it be entirely local, affecting directly only a limited number of nerves? To this question the answer may unhesitatingly be given, that the predisposing or irritating cause may be wholly local, and confined to any portion of the cen- tral or peripheral nervous system. An irritation set up in any nerve gives rise to the greatest variety of disturbances in any or all other EEFLEX lEEITATIONS. 19 parts of the organism, however distant. Hence it is not logically necessary to suppose a universally per- vading or even a central initial irritation in order to explain the neuropathic predisposition. The experi- ments of Sir Charles Bell, of Marshall Hall, and of many subsequent observers, have so clearly proved this doctrine that it is beyond question. Dr. Brown- Sequard, in enumerating some of the effects of tick- ling the sole of the foot in a large number of sub- jects, speaks, among other things, of laughter, of tears, of jerks of one or both limbs of a side, or of all the limbs, of tremblings and spasms, while in some instances no effect was manifest. If it be admitted that the neuropathic predisposi- tion may consist of a local irritation and not neces- sarily of some peculiar and undemonstrated general "modifications of molecular arrangements," we are prepared to inquire whether, inasmuch as this tendency is transmitted from parent to child, the evil may not consist of some peculiarity of anatomical structure, or of physiological adaptations, which is inconsistent with the most regular and easy performance of the function of a part or parts ? This would unquestionably be a reasonable hypoth- esis, and we are at once led to inquire whether mechan- ical or physiological peculiarities of this sort are likely to occur in a sufficiently uniform manner to enable us to classify them and to determine to which, if to any class, any very considerable number of irrita- tions may be attributed ; or whether, in other words, certain classes of mechanical peculiarities are more 20 FUNCTIONAL NERVOUS AFFECTIONS. than usually liable to become factors of physiologi- cal disturbance. Manifestly, any hypothesis which assumes this must, to be sustained, be based upon many and long- continued observations conducted in a spirit of judi- cial independence, and free from all such bias as might result from occasional and exceptional experi- ences. It is believed that the views advanced in this es- say are thus based, and that a Just regard for the experiences and teachings of all who have contributed to this important subject has been observed. The conclusions here announced are based upon observations in twenty-six hundred and ninety- two cases of nervous diseases in private practice and of a considerable number of cases in public institu- tions,* which have been made with as much care and precision as the exacting demands of an active pro- fessional life would permit. That in the course of these observations individ- ual cases have failed to receive due attention is doubt- less true; but that in the general results of this in- vestigation the conclusions reached are accurate, the author believes that he can affirm without presump- tion. In the confirmed belief that the neuropathic pre- disposition must of necessity be the manifestation of many structural peculiarities located in various parts of the organism, any of which may descend from parent to child, but which do not necessarily so de- * Up to the time of writing, in 1883. GENERAL PROPOSITION. 21 scend, and fully appreciating the influence of sucli immediate and modifying causes as have been already mentioned, the conclusion arrived at in this investi- gation may be stated in the following proposition: Difficulties attending the functions of accommo- dating and of adjusting the eyes in the act of vision, or irritations arising from the nerves involved in these processes, are among the most prolific sources of nervous disturbances, and more frequently than other conditions constitute a neuropathic tendency. A doctrine so much at variance with the ordinary beliefs must, of necessity, excite suspicion that the proposition has been based upon insufficient data, or that observations have been imperfectly made. That neither of these suspicions is correct it is hoped may be demonstrated to the entire satisfaction of reason- able inquirers. If to the reader the proposition appears extreme, and tending, at best, to the recognition of a single class of causes to the exclusion of others, he is cau- tioned to observe that the proposition fully recog- nizes any and all causes of nervous irritation, and that the influences indicated by it are held to be pre-eminent, but not exclusive permanent causes. If, in this discussion, greater importance will be conceded to these than to other influences, it will be from no unmindfulness of the possibility of other conditions acting as irritating influences, or that cer- tain known or unknown agencies may give character to the results of irritation arising from the influences here specfied. 22 FUNCTIONAL NERVOUS AFFECTIONS. Let it be remembered that it has been universally conceded that the nature of the neuropathic tendency- is unknown. If one pre-eminently important element of that tendency is here demonstrated, it is not to be re- jected because it may not include the whole. In the explanation of the etiology and treatment of disease, neither settled theories nor novel doctrines can be proved, except as they are confirmed by un- doubted facts. Nor can isolated facts, nor facts di- vested of their natural environments, be accepted as valid evidence in support of theories, old or new. The facts must be uniform, occurring so regularly as sequences as to demonstrate that they are conse- quences. Unless the skilled observer is able to pre- dict with a reasonable degree of accuracy the result of certain combinations of circumstances, such results must be considered accidental. Before presenting facts upon which this proposi- tion is based, it will be well to inquire whether it is reasonable to suppose that irritation sufficient to cause or perpetuate a long-continued series of disordered nervous phenomena can arise from the performance of the functions of the eyes, and, if so, what is the origin of the supposed irritation? In order to arrive at a fair understanding of this subject, it will be in place to review some points in the theory of adjustments of the eyes in the act of vision, which, although well known to oculists, may be less familiar to those not specially engaged in ex- amining the defects of vision. EEFRACTIVE MEDIA OF THE EYE. 23 When rays of light fall upon the transparent sur- face of a healthy eye, they jDass beyond the surface, through the pupil, and through the transparent media to the retina. If a distinct image is formed, the rays must unite at the focus of the eye, which is the reti- na. To this end, the rays are refracted as they pass through the media. In the normal eye the refractive power is such that parallel rays, rays from objects at infinite distance, unite precisely at the retina. If ob- jects are to be clearly perceived at different distances, it is obvious that some provision must exist for chang- ing the focus of the eye ; for, while rays from a dis- tant object are parallel, those from near objects di- verge as they pro- ceed from the ob- ject to the eye. These diverging rays must be more strongly refracted, in order to meet at the retina, than parallel rays. In the refracting me- dia of the eye there are different fac- tors ; they are the anterior surface of the cornea, the an- terior surface of the lens, and the anterior surface of the vitreous humor. The relations of these parts and the retina may be briefly described as follows : 3 Fig. 1. — Diagrammatic section of the eye. s, sclera ; c. cornea ; i, iris ; ch, choroid ; r, re- tina ; ah, aqueous humor ; cl, crystalline lens ; v7i, vitreous humor ; cap, capsule ; on, optic nerve ; ml, macula lutea. 24 FUNCTIONAL NERVOUS AFFECTIONS. The tough protective shell of the eye, the sclera, maintains the form and holds in place the transparent humors which fill its space. At the front of the eye- ball this hard coat is so modified in structure as to constitute the transparent cornea. Behind this trans- parent substance is the curtain, the ii^is, near the cen- ter of which is an opening, the pupil. The crystalline lens lies behind the pupil, and the considerable space behind the lens and in front of the retina is occupied by the vitreous humor. Light from a luminous object passes through the cornea and pupillary opening, then through the crystalline lens, and thence to the retina. Now, in order to maintain such a condition of these refracting media that objects at different distances may be seen accurately, there must be some change in the relative refracting power ; in other words, the eye must be capable of altering its focus. In the well-known optical instrument, the opera- glass, the focus is adjusted by turning a screw, so that the lenses approach or recede from each other ; in the eye the change is produced by alterations in the con- vexity of the crystalline lens through the action of the ciliary muscle upon it. The lens is held in its relation to the muscle by its delicate envelope, the capsule, and the muscle is capable of contraction under the influ- ence of the will, in which case the opening becomes smaller. When this happens, the lens, by virtue of its elasticity, becomes more convex, and its refracting power is increased. When, on the contrary, the muscle returns to a state of rest, the inner border approaches the outer FUNCTION OF ACCOMMODATION. 35 border, the opening is enlarged, and the lens, com- pressed by the greater tension of the capsule, becomes less convex. In the former case it is said to be accom- modated for near points, in the latter for distaijce ; and the power of thus changing the form of the lens, and consequently the focus of the eye, is called the function of accommodation. This function of accommodation is always brought into use when the eye is directed to points at different distances from it. If the eye is of the most perfect form and the media in the most perfect condition, this function is per- formed with ease, the ciliary muscle having abundant strength to execute the changes to any reasonable ex- tent without undue fatigue. But it so happens that this function is not always performed in this easy and regular manner. Eyes are not all constituted in the most perfect fashion, nor does the crystalline lens always maintain a uniform degree of elasticity ; hence, not infrequently the ciliary muscle is called upon to perform an amount of labor quite exhausting ; or it may be, on account of certain irregularities in the demands upon it, the muscle is subjected to a perplexity or fret from which it is easily exhausted. Some of the defects in the form of the eye which have an influence upon the accommodation may be easily comprehended by comparing certain well-under- stood anomalies with the ideal, or, as it is called, the emmetropic eye. In the emmetropic eye parallel rays are so refract- 26 FUNCTIONAL NERVOUS AFFECTIONS. ed that, without an effort on the part of the muscle of accommodation, they meet at the back of the eye. This normal eye is, then, in a passive condition or state of complete rest when looking at a distant ob ject; but as the object approaches within what is called "finite" distance, which in ophthalmology is within six metres, the act of accommodation must be exercised. This in the ideal eye demands a moderate muscular exertion. But in the hypermetropic eye, which is a short eye,* the refractive media are not sufficient to bring parallel rays to a focus at the retina. In such an eye the rays, if permitted to pass beyond the retina, would unite in a focus behind it. In such an eye, clear vision can only be obtained by giving to the rays a greater re- fraction than occurs when the eye is passive. Such additional refraction might, if no other means existed, be supplied by a convex lens, but ordinarily the ob- ject is attained by causing the crystalline lens to assume greater convexity — in other words, by the act of accommodation. In the hypermetropic eye, then, accommodation must be exercised even in looking at the most dis- tant object ; and as long as the eye continues to see clearly at any distance, this exertion must be contin- ued. If the object to be seen is near the eye, the effort must be excessive. Hence, such an eye is never at rest when seeing at all, and is performing excessive labor when looking at near points. In a certain pro- portion of hypermetropic eyes the ciliary muscle, even * The " short eye " must not be confounded with " near-sight." ERRORS OF REFRACTION. 27 by the highest exercise of its power, is unable to ac- complish the task of accommodation, and such eyes obtain no clearly defined images except by artificial aid. The myopic eye, on the contrary, is too long, and parallel rays refracted in the same manner as in the emmetroi^ic eye cross before reaching the retina. Cir- cles .of diffusion take the place of distinct images when distant objects are to be viewed, and, except for ob- jects brought within the focus of the eye, vision is materially impaired. Again, the refracting surfaces of the eye may be irregular in their curvature, in which case a pencil of rays will not be brought to a point. This irregu- larity is often found in the cornea. The curvature in one meridian may be greater or less than in that at right angles to it. In this case we have a con- dition called astigmatism. These errors are called errors of refraction ; and there are other defects which relate more especially to the act of accommodation. Thus, after the age of fifty, the crystalline lens in the best-formed eyes has lost so much of its elasticity that the act of accom- modation for near objects becomes quite difficult, and this difficulty increases year by year, until at the age of seventy the function of accommodation is practi- cally lost. Debility or paralysis of the ciliary muscles may also cause difficult accommodation. To illustrate the effect of these and other defective conditions of refraction and accommodation, a single condition may be selected as an example. 28 FUNCTIONAl. NERVOUS AFFECTIONS. The effects of hypermetropia can perhaps be more easily understood than the effects of other errors. For that reason, and not because of its greater im- portance compared with other anomalies, these effects are more fully discussed here. An examination of the results of this condition must serve to illustrate the disadvantages of the other anomalous conditions, notwithstanding the fact that the disturbances from the different conditions arise in various ways. As it has been shown, the hypermetropic eye is short, and rays of light do not come to a focus at the retina without an effort of accommodation. If the degree of hypermetropia is moderate, and the ciliary muscle is vigorous, objects at a distance (in the ex- amination of visual conditions a distance of about six metres or more is called infinite distance) may be seen clearly without any percej)tible strain upon the eye. If, however, the eye is directed for consider- able periods of time to near objects, as in reading, the muscle is overtasked. All know how a light weight seems to grow heavy as one holds it in the hand while the arm is extended. In the same man- ner the continued and unnatural tension of the ciliary muscle of the far-sighted eye may become at length a source of much weariness, and it is also seen that while the normal eye is at rest when accommodated for distance and only slightly exerted when accom- modated for near points, the hypermetropic eye is never at rest except when closed. But a condition of much more importance than the simple continued strain of muscle is found in hypermetropic vision. BINOCULAE VISION. 29 When tlie two eyes are fixed on an object, the image of the point fixed is at the yellow spot in the retina, and lines drawTi from the yellow spot of the retina of each eye through the center of the pupil would meet at the point fixed. If the eyes gaze at an ob- ject at the horizon, these visual lines will be practi- cally parallel; but if their view is fixed upon a near object, these lines are converged. The converging of the eyes is seen when one looks at a i)encil held a few inches in front of the face. This convergence is effected by long, straight muscles located in the orbit and attached to the outer shell of the eye. There are several of these long muscles, but for our imme- diate purpose only two belonging to each eye may be mentioned : the external rectus, or straight muscle, which tends to keep the visual axes removed from each other ; and the internal rectus, which tends to converge these axis. If the lines converge exactly in proportion to the proximity of the object, single vis- ion is obtained wdth the two eyes. This associated or binocular vision is essential to exact notions of the position of objects in space, and, if not maintained, much confusion of impressions results. It will at once be seen that the degree of accom- modation of the eyes singly, and of the convergence of the optic axes, must be in harmony. For if the accommodation is fixed for one point while the con- vergence is for a point of greater or less proximity, there must result an absence of perfect definition, or the presence of double images. Hence the effort of the ciliary muscle in accommodating, and of the recti 30 FUNCTIONAL NERVOUS AFFECTIONS. muscles in convergence, must be not only simulta- neous, but in precise proportion to each, other. This being the case, a pair of normal eyes, accommodated for a given distance, will converge for the same dis- tance. These muscular efforts are directed and regu- lated by nervous impulse, and in this case the im- pulse is exactly proportioned. Reverting now to the hypermetropic eye, it will be seen that a greater nervous impulse and more active muscular contrac- tion must occur in accommodation than in the nor- mal eye. Let it be supposed that the muscular ef- fort of accommodation for a point one metre distant for a given hyperopic eye is equal to the effort in the normal eye for a point situated at half that distance ; then if the effort at convergence equals the effort at accommodation, and the eye is focused for a point one metre distant, the axes of the two eyes will meet at a point not so far removed, and the eyes are not in their axes adjusted for the point for which they are individually focused, and confusion results. In such a case continual compromising adjustments must be made and great nervous perplexity and dis- appointed nervous action must occur, for no sooner is one part of the adjustment corrected than the other is wrong. It is to this nervous perplexity, more than to the actual strain of muscle, that the weariness and pain characteristic of hypermetropia are due. The principle just stated may be illustrated by the experience of young persons who, having normal eyes, attempt to use strong magnifying spectacles. PERPLEXITY FEOM ASSOCIATED MOVEMENTS. 31 At first a sense of slight inconvenience is felt ; but, if the attempt be continued for a considerable time, vertigo, nausea, and vomiting may result. This re- sult does not pccur if one of the eyes is closed. Hence, the disturbance is in the confusion arising from efforts at perfect binocular vision. But pre- cisely this confusion of effort exists in the hyper- metropic person, and if the continuance of such a course of perplexity for a few minutes or hours will result in so serious nervous disturbance as is shown in the illustration, is it not reasonable to suppose that a similar confusion of effort continued through many years may constitute a permanent source of nervous irritation ? Similar i)erplexity results when either the internal or external recti or other long muscles are insufficient to the performance of their functions by the normal nervous impulse. A difficult and more complicated perx)lexity arises in case of as- tigmatism, and still other nervous confusion is the result of myopia. Hence all these abnormal states, whether from defects in the form of the eyes, or in the motor apparatus involved in associated movements, may give rise to nervous perplexity and irritation. But it has been shown that the effects of such per- plexity or irritation in one part may be experienced in a distant part, and this principle is illustrated in the case of the young person who may induce vomiting by using magnifying spectacles. However reasonable such a theory may appear, it can not be accepted as of practical value until it is shown that practical results may be deduced from its 32 FUNCTIONAL NERVOUS AFFECTIONS. application. I shall attempt to show that such results may follow with a surprising uniformity — first, by citing a single instance illustrating the effect of cor- recting each of the more commonly recognized defects of refraction and association ; second, by consider- ing at greater length several of the more familiar conditions of nervous disturbance ; and third, by at- tempting to show the results of such corrections in a given number of consecutive nervous disorders of serious nature. The first observation is the case of a lad aged seven years, whose mother brought him for treatment of the eyes in 1873. The immediate reason for the consultation was pain experienced in and above the eyes. He was nervous, suffering severely from chorea, from which he had not been free for two years. He was weak, had no inclination for the amusements of childhood, and was often ill in various ways. He was found to have hypermetropia in high degree. Appro- priate glasses were directed, which greatly pleased him. Recovery from his nervous troubles commenced at once. The change was rapid and remarkable. The lad continued to gain strength, and was, within a few weeks, in all respects in better health than ever he had been before. Although ten years have passed, there has been no return of nervous troubles. A lady, aged twenty-one, had suffered so greatly from facial neuralgia during many years that, among other radical measures for relief, she had submitted, by medical advice, to the extraction of all her teeth, notwithstanding they were sound. She.was found to ILLUSTRATIVE CASES. 33 have astigmatism, and strong cylindrical glasses were prescribed. The neuralgic paroxysms ceased within a few days, and have not returned during eight years. A gentleman, aged twenty-eight, an extremely neu- rotic subject, was seen in January, 1877. He had for several years suffered from dorso-lumbar neuralgia. He was extremely sensitive to the influence of cold. A slight draught of air impinging upon the back was sufficient to bring on a paroxysm so severe as to con- fine him several days in his bed. He slept poorly, and so excessive was his general . nervous derangement that he sometimes felt himself upon the boundary of insanity. He belonged to a neurotic family. His mother died insane. One of his brothers was insane, and a sister had been an invalid for several years from some nervous disorder. He was myopic, with a slight astigmatism. Glasses to meet these conditions were prescribed and used. Mne months later he called to say that he was entirely cured, and that the relief had been immediate. A lady who had suffered from facial neuralgia of intense character during many years, was found to have insufficiency of the internal recti muscles. Te- notomy of one of the external recti was performed, since which time, although six years have elapsed, she has had no attack of her complaint. These instances serve as illustrations of irritation arising from uncomplicated errors of refraction, or of association, and of the relief often obtained by the correction of these uncomplicated errors. • But it often happens that these anomalies are not 34 FUNCTIONAL NERVOUS AFFECTIONS. uncomplicateid. Thus, refractive errors, sucli as hy- permetropia or myopia, are often associated with mus- cular insufficiencies, either of those directing the eyes laterally, or of those which move them in the vertical direction. Again, insufficiency of either of these mus- cles may be associated with weakness of the muscle of accommodation. These are but a few of the com- plications which may be found, and, in many of these nervous complaints in which the predisposing irrita- tion is found in the eyes and their motor apparatus, the simple correction of a refractive error is by no means sufficient to bring relief to the nervous condi- tion. AYhen once a neuralgic, choreic, or epileptic habit has been long established, not only may it be necessary to remove the principal source of irritation, but all irritation, before the habit will be discon- tinued. It must not, therefore, be supposed, even if the hypothesis that refractive and muscular errors of the eyes constitute a very important factor in the neuropathic condition, that the simple adjustment of a pair of glasses, or the simple relaxation of a muscle, must of necessity establish the cure of a nervous disease. The irritation experienced in and about the eyes, and in the forehead and temples, as a result of ame- tropia or muscular anomalies, is called asthenoj^ia. It is a complaint for which oculists are very frequent- ly consulted, and doubtless yields more readily than complaints arising from the same cause more distantly located, or of more severe nature ; yet it is well known to oculists that even asthenopia does not al- CEPHALALGIA OR HEADACHE. 35 ways yield to such simple measures as have been mentioned. Hence the highest skill and most patient effort may be demanded for the removal of ocular disturbances which may cause nervous troubles, and the failure of efforts directed only to some prominent ocular defect would not of necessity argue against the probability that the eyes may, after all, be the seat of trouble. Bearing this in mind, we are prepared to examine more in detail a few forms of neuroses and thek rela- tions to ocular defects. CEPHALALGIA OE HEADACHE. The form of nervous disturbance more common than any other, perhaj)s, is headache. The habitual sufferers from this comi^laint are everywhere, and, in- asmuch as the subjects of the disorder are usually able to be about, and generally to attend to the ordi- nary duties of life, they are forced to surrender them- selves to the ever-returning torture with as much resig- nation as possible ; and, after trying many remedies, almost all of which may, for a brief period, seem to modify their sufferings, they at length submit passive- ly to their fate, with the comforting assurance that the disorder is constitutional, and that nothing can be done. Although headaches take a variety of forms, an outline of the most characteristic features of the dis- order may be drawn in such a general manner that the details of the picture may be easily filled in for an individual case. 36 FUNCTIONAL NERVOUS AFFECTIONS. The j)ain most usually attacks the temples, the supra-orbital and the occipital regions, the parts with- in the orbit, and more rarely the top of the head. It is more or less paroxysmal, sometimes occurring with comparative regularity, but frequently arising after a period of anxiety, care, worry, or excitement. In many cases the pain is continuous, and parox- ysms consist simply of increase of the ordinary suf- fering. In the majority of females examined who have been habitual sufferers from headache, there has been found habitual pain at the origin of the tra- pezius muscles, at the point over the extremity of the spinous process of the seventh cervical vertebra, and at the lower angles of the scapulae. Less com- mon, but quite characteristic pains accompanying headache are between the angles of the scapulae and at the lower part of the dorsal region. It is worthy of observation that in general, if pain is habitually experienced at the lower angles of the scapulae, it is rarely found at the point over the spinous processes of the vertebrae situated between those points; and, again, if pain is habitual over the spinous process of the seventh cervical vertebra, it may be presumed to exist, although it is not invariably found, at one of the other locations below it. These pains occur much less frequently in men, who, more than women, suffer from dull pains at the occipital region. This occipi- tal pain, which is invariably located in the scalp and occipital muscle, is very frequently and incorrectly spoken of, sometimes even in medical literature, as "pain at the base of the brain." ATTENDANT SYMPTOMS NOT CAUSATIVE. 37 Other sympathetic pains are, at the turn of the shoulders and along the course of the triceps muscle, and in the upper portion of the chest. Patients suffering from headaches are frequently dyspeptics ; they often suffer from insomnia, and ha- bitual constipation is also a not infrequent attendant condition. To the various conditions just named, the head- aches are often attributed, and many patients feel sure that they can account for their headaches as of stomachic origin, because they habitually suffer from disturbance of the stomach at the time of, or Just before, the paroxysm of headache. That these are simply attendant symptoms and not causative influ- ences, will be seen as we advance, and the fact that an indiscretion in diet, or an enforced loss of sleep, may act as an immediate cause, will be found to be explained on the principle of increased demand upon nervous energies already rendered inadequate to the ordinary demands of the system, and that this in- creased demand acts in the same manner as would other calls upon the nervous energies. Habitual sufferers from headaches, although often persons of highest mental culture and of superior intellectual endowments, are liable to suffer from chronic lassitude and inaptitude to set themselves about any employment, especially if it demands much mental exercise. In some cases a confusion of ideas is so conspicuous a symptom that patients express fears of approaching insanity. There is, in a large proportion of instances, a general nervous imtabil- 38 FUNCTIONAL NERVOUS AFFECTIONS. ity, inability to continuous exertion, and mental de- pression. Still other cases are so characterized by general impaired functional activity, that the princi- pal local manifestation, the headache, is apparently a secondary subject of attention. Such patients ex- hibit symptoms varying in a considerable degree, ac- cording to the sex of the individual, and the cases are known as spinal irritation, neurasthenia, etc., conditions to which attention will be presently di- rected. Chronic headaches are common among those who inherit a neuropathic tendency; by far the greatest number of subjects acquiring the predisposition by inheritance. Certain collateral influences modify the disease in a marked degree. Thus, a residence in a malarial district may give to the complaint a more dis- tinctly periodical tendency, and subjects of headache passing an active life in the open air will, in general, ex]3erience less of the associated neuralgic j)ains in the back and sides than persons of sedentary habits. The most important facts relating to the etiology of the complaint may be briefly recapitulated as fol- lows : It is an exceedingly chronic disorder, often relieved temporarily, but rarely, if ever, permanently cured by medicines. It is often traceable to the earli- est years of the patient. The tendency is frequently, if not generally, hereditary. It is usually intermit- ting, and demands upon the nervous energies, slightly in excess of those ordinarily required, act as imme- diate causes. We also find that other symptoms of nervous disturbance, such as insomnia, dyspei)sia, and NERVOUS SYMPTOMS INTERCHANGEABLE. 39 pains in various localities, are frequent attendant dis- orders. These facts lead to the conclusion that the cause is permanent, and in most cases commensurate with the life of the patient ; that the irritation or exhaustion affects the nervous centers and is reflected to various parts at a distance from the head as well as to the head itself. Hence, the manifestations of nervous exhaus- tion or irritation are interchangeable. Thus it is that one in whom the irritation may have been for a long time exhibited as habitual headache may, from some reason, assignable or otherwise, afterward suffer from dyspepsia, neuralgia, or other forms of nervous dis- order from the same irritation, and such a change in the form of disorder does not indicate a cure of the first disease, but only a different manifestation of the same trouble from the same cause. We also find that certain modifying influences, such as the manner of life, the location of residence, and the occupation of the individual, contribute to lend certain characteristics to the complaint. We are, then, applying all these facts, to search for some cause which shall most generally answer to all these conditions. It must be permanent, often inher- ited. It is not of necessity situated at the seat of pain, and is as capable of inducing pain or distress in one part as in another. Such a cause must be ana- tomical, and it is reasonable to assume that it acts by causing inordinate demand ujDon the nervous energies in the performance of some function or functions, thus reducing the ordinary standard of nervous power in 40 FUNCTIONAL NERVOUS AFFECTIONS. such a manner that slight additional demands cause marked irregularity of nervous action, permitting agencies which might not otherwise induce disease in the individual to become under these circumstances, capable of exerting important modifying influences. It may be said in general that any anatomical con- dition which would render the execution of an impor- tant and constantly performed function difficult might, by so reducing the amount of nervous energy, become a neuropathic predisposition. This principle being established, it remains to de- termine, if possible, whether difficulties in performing any one function more often act as such predisposi- tion, than those attending the performance of other functions. This question can not be satisfactorily settled upon theoretical principles independently of practical re- sults. If it should theoretically appear probable that this irritating or exhausting influence is to be found more frequently located in one organ or set of organs than another, and should assistance in the performance of the functions of that organ or set of organs be quite uniformly followed by a relief from the disturbances previously experienced, a reasonable ground would exist for concluding that the most general cause had been discovered. It has already been shown that, in the performance of the visual act, difficulties of no insignificant char- acter are very frequently encountered. These diffi- culties are often permanent, and are to a great extent hereditary. The nervous strain arising from visual PRESENT CIVILIZATION AND NEUROSES. 41 defects, organic or functional, is great in proportion as the present civilization makes greater demands upon the visual function than has any previous civilization ; and the neuroses of the character which we are con- sidering are notably more numerous at the present time than in former times. That this increase in nerv- ous disorders is not a result of any deterioration of physical power among the civilized nations of the present time is apparent when we remember that the duration of life is now greater and the average capaci- ty of labor is probably greater among civilized people of the present age than among those of former cent- uries. If it can be shown that a very considerable propor- tion of chronic headaches are relieved by the removal of exhausting or perplexing conditions from the eyes, the theory that such conditions are among the initial causes will be established. A few cases somewhat in detail will illustrate the manner in which such relief is obtained. These cases do not differ essentially from several hundreds of others, either in their general features or in the re- sults of treatment : Mr. W. N. B., consulted March 16, 1881. He has for six years past suffered extreme pain in the top of the head and in the occipital and tem- poral regions. He is never free from pain when awake. He is in an extremely irritable state, rests poorly at night, has more or less backache, and is always constipated. His face is usually flushed, although he is of strictly temperate habits ; and 42 FUNCTIONAL NERVOUS AFFECTIONS. he is mucli troubled with, vertigo. He has been forced to resign his position as secretary in a large public institution, and during the two months i>Ye- ceding his visit has been an inmate of an excellent hospital, where he has been under treatment. Al- though somewhat rested, he has obtained no relief from the nervous symptoms. He was found to have hypermetropia 2*50 dioi)trics, and insufficiency of the external recti muscles. Convex glasses 1*5 D. were prescribed, which were soon replaced by convex 2 "00 D. Partial tenotomy of one of the internal recti muscles was made, and the operation was soon followed by a similar one on the other eye. The patient rapidly improved, and was in a few weeks able to return to clerical duty. This, however, he afterward resigned for a more active life, and his health has remained entirely good during the interval of two and a half years. Mrs. J. D., aged fifty-seven, consulted February 24, 1881. Has had headaches since she was fifteen years old. Is a large, well-developed woman, ap- parently vigorous. Paroxysms occur at intervals of from once a week to once in two weeks. They are of great intensity, and not infrequently quite alarming to friends and physicians. In the inter- vals she suffers from sciatica, from mental depres- sion, from dull headaches, palpitation of the heart, and dyspepsia. Two sisters are subject to chronic headaches. Examination of the eyes shows that she has a EXERCISE OF OCULAR MUSCLES. 43 moderate degree of astigmatism and deficient ad- ducting force. Convex cylinders were prescribed and used witli a combination of spherical and cylindrical for reading purposes, and the adducting power was increased by systematic exercise of the internal recti muscles with prisms. March 23d, has perfect converging power. Has had no headache during the past two weeks. April 10, 1883. Has during the interval of more than two years been entirely free from headaches. Has no more dyspepsia, palpitation, or sciatica, and her present call is only in regard to a change of reading-glasses. Reference is made in the above case to exercise of the ocular muscles, which is accomplished by means of prisms which the ocular muscles are called upon to overcome in order to maintain single vision ; prisms of gradually increasing strength being employed. As other references to such exercising of the ocular muscles will be made, it is proper to anticipate with a few words what will be stated more at length further on in regard to it. Exercise having the same object in view and per- formed in a somewhat similar manner to that which will be hereafter described, was formerly employed to some extent for the relief of insufiiciency of the in- ternal recti muscles. As the experience of oculists generally proved that, in the majority of cases in which insufficiency arising from actual disproportion of the recti muscles exists, this is quite inadequate, 44 FUNCTIONAL NERVOUS AFFECTIONS. the exercise has been for several years very generally abandoned. In the cases in which it is referred to in this essay, there has existed, for the most part, an insufficient ad- ducting energy, but no very considerable degree of in- sufficiency such as would be shown by the dot and line test of Yon Graefe. The distinction between the two forms of insuffi- ciency will be dwelt upon more at length in its appro- priate place, and it remains only to say here that such exercise in suitable cases proves of infinite benefit. Hereafter the term "insufficient adducting power" will be used to describe the condition amenable to such exercises, while the term "insufficiency of the internal or external recti muscles of a stated number of de- grees " will express the condition commonly described as insufficiency of the recti muscles. The following case illustrates a very frequent cause of headache and of other nervous symptoms : A young gentleman had for several years suffered almost continuous headache during waking hours. His plans of life had been seriously modified by the constant torture he suffered, and he was often in charge of a physician. Deficient energy of the ciliary muscles in the act of accommodation was supposed to be the cause of his trouble. Tablets containing small quantities of ex- tract of Calabar bean were placed upon the eyes daily for a few days in succession, followed by the occa- sional but less frequent use of the same agent for two weeks. At the end of that time he was greatly RELIEF FROM REMOVAL OF CAUSE. 45 improved, and in a month quite well of his headaches. Four years have passed with no serious return of his old complaint, and a threatened attack can be averted by a single instillation of a solution of eserine into the eyes. Severe and long- continued headaches are sometimes accompanied by excessive symptoms of exhaustion, coldness of the extremities, and loss of muscular elas- ticity. Annie W., age ten years, was brought for ex- amination in September, 1880. She had been al- ways subject to severe headaches, located in the temples and back of the head. Although rarely free from suffering, her pains are greater if she at- tempts to look at books. She is very pale and thin ; walks feebly, and seems quite exhausted with very moderate exercise. The facial mus- cles are so little active that she seems expression- less. Her speech lacks energy, and in all respects she seems to be in a state of great nervous ex- haustion. There was found in this case marked insuflB.ciency of the external recti muscles and very slight adductive power when accommodation was relaxed. After increasing the adducting power by exercise, partial tenotomy of the internal rectus was performed under the influence of chloroform. The child commenced very soon to gain strength and elasticity ; expression came to the face and vigor to the limbs ; the headaches ceased and mental energy followed. She has continued well during the thi-ee 46 FUNCTIONAL NERVOUS AFFECTIONS. years, and is now advanced in her studies beyond most of her companions of the same age. The two portraits of Plate I, reproduced from photographs, represent a child ten years of age, who from infancy had been the victim of head- aches. She was feeble, always tired, and rarely free from pain. Attempts to send her to school had proved unsuccessful, for she no sooner com- menced attendance than she became prostrated. She had insufficiency of the externi, and operations for its relief was made, upon one eye June 8, 1883, and upon the other June 12th. It is needless to tell one who examines these two pictures that the change was marvelous. The weary, heavy, discour- aged aspect of the child as shown by the portrait of June 8th is in remarkable contrast with that of June 20th, where vivacity and courage are embodied in her expression. The child returned home to enter school, where she has done excel- lent work. In the cases above cited, headaches have been re- lieved by the removal of irritation induced by — 1. Hy- permetropia, with insufficiency of the external recti ; 2. Astigmatism, with enfeebled adducting force ; 3. Enfeebled energy of the muscles of accommodation ; and, 4. Insufficiency of the external recti muscles uncomplicated with any very important refractive error. It will thus appear that these various conditions of refractive and muscular anomalies may act as dispos- ing causes of headaches, and that the removal of the f^^:a»M:_. .jj^ta^- ^*f^ jm GENEEAL RESULTS IN CEPHALALGIA. 47 irritation arising from such conditions is sufficient to afford permanent relief to the nervous suffering. The number of cases of chronic headache* in the jjrivate practice of the author, in which examinations of the ocular conditions have been made, is twelve hundred and eighty. For nearly all these, advice in regard to the correction of the ocular defects has been rendered ; but, inasmuch as the period during which these examinations have been made extends through several years, it is manifest that it is impossible to know the result of this advice in all cases, A very large proportion of these are transient cases, in which a single consultation has concluded the relation of physician and patient, and as many of the cases reside in cities distant from the residence of the writer, some even of those who receive treatment for a longer time are lost to observation. In order, however, to arrive at some basis of facts from which one not in the constant observation of these phenomena may be enabled to draw some conclusion as to their value, an analysis of the results in one hundred consecutive cases of chronic headache is here given. The list extends backward from December 31, 1882, to the 2d of June of the same year. This, while allowing sufficient time to have elapsed since the most recent date, to determine the permanent results, is also sufficiently recent to enable a recollection of the cases in some measure to supple- ment the written record. Proceeding, then, to the analysis of these cases, it * Chronic in the sense of continuing during more than one and in general during several years. 48 FUNCTIONAL NERVOUS AFFECTIONS. is found that of tlie number, nothing is known of the patients after their first consultation in twenty-two cases. In five other cases, in which more than a single visit was made, no knowledge of the subsequent his- tory is possessed. Sixty-one are known to have ob- tained permanent relief. Mne are known to have received temporary and marked improvement, while in three cases no improvement resulted. If we exclude the twenty-seven cases the history of which, since the examinations or after a very few calls, are unknown, we shall find that the proportion to one hundred is as follows : Permanently relieved 83*6 per cent. Improved 12'4 " Not cured 4 " 100 It should be observed, in passing, that the cases upon which these statistics are based are in all re- spects typical cases of chronic headache, of which the illustrative cases given above are fair examples. No cases of simple asthenopia or of temporary headaches are included. It should be further remarked that in these cases drugs have not been administered, except in rare in- stances, for temporary relief of some other symptom, and in no case can the influence of drugs be re- garded as a factor in the result of the treatment. This statement will also apply to classes of cases here- after to be reported. In fact, the results in these cases must be attributed solely to the removal of the CEPHALALGIA. 49 difficulties incident to the performance of tlie visual act. As has already been said, every oculist recognizes the fact that asthenopia is a complaint resulting gener- ally from ocular defects or insufficiencies of the ocular muscles. Yet it is equally well known that this more immediate and much less severe form of irritation does not always yield to the means employed for its treat- ment. But if we compare the results of treatment of asthenopia with the results obtained in the treatment of headaches by similar means, we can not fail to see that the latter form of complaint yields as often to treatment directed to correction of anomalies of re- fraction and accommodation or of muscular insuffi- ciencies as does the former. Hence we may logically draw the conclusion that headaches are as generally the result of disturbing ocular conditions as is asthe- nopia. It is to be further observed that the relief is not the result of temporary stimulation of nervous energy, such as might result from the use of electricity, or of certain drugs, or a change of air or surroundings. Either or all of these measures might bring relief in certain cases, but if the fundamental cause remains, it is only relief, and can not be properly regarded as a cure, of the predisposing tendency. In cases of temporary nervous disturbance, result- ing in headaches, the agencies above mentioned may be used with advantage, but they certainly have no power to remove an hereditary cause. Further consideration of the treatment of this 50 FUNCTIONAL NEEVOUS AFFECTIONS. special class of troubles may be reserved for consid- eration under the general discussion of therapeutical measures in nervous comi)laints. Nearly related to this class of troubles is migraine, a complaint often classed with neuralgia, but which has characteristics so clearly defined that it may well rank as a distinct form of nervous disturbance. MIGEAIJiTE, OR SICK-HEADACHE. Paroxysms occur with greater or less regularity in respect to time, the intervals being in some cases only a few days, in others a month or more. The attack commences in most cases with a feeling of lassitude and dull headache, the eyes are painful, and the act of turning them quickly or far is attended with dis- tress. The effect of light is disagreeable, and there is mental disquietude. In some instances the attack is ushered in by great disturbance of vision, sometimes described as glimmerings and confusion. At other times the visual defect assumes the form of hemiopia, or even of complete blindness. The visual disturbance lasts from a few seconds to an hour, and such attacks are known as "blind headaches." The subject of an attack, after a few hours of these premonitory symptoms, resorts to the bed, the j^ain over and through the eyes becoming more and more intense, and the effect of light more tormenting. Slight sounds or feeble currents of air are often unendurable, and nausea and vomiting supervene. The pain is in many cases confined to one side, and in some uniform- ly to the same side, in various attacks. In others the MIGRAINE. 51 pain is alternately located on one or the other side, and, in case of visual disturbance of one eye only, the headache is often situated upon the opposite side of the head to the eye affected. The headache as well as the visual disturbance may, however, be bi- lateral. In a few cases of '•'blind" headaches, in which the fundus of the eyes have been examined with the oph- thalmoscope during the period of visual disturbance^ the retina has been found pale and brilliant, the optic disc unusually white, and the main arteries somewhat irregularly contracted in their course. In these cases the field of vision has been found to be contracted in a striking manner, in some instances one half of the field being completely lost, while in others the central field was gone, imperfect sight only remaining at the periphery. A night's sleep may bring relief, or the paroxysm may continue for several days, during which delirium or loss of consciousness may become prominent symp- toms. The attack being over, there may remain some symptoms of the nervous prostration for a day or two, but the patient is soon more than usually well for a period of one or several days, and the subjects of the complaint are often extremely vivacious and energetic in the intervals between the attacks. This is, however, not always the case, as a certain propor- tion of the subjects of this malady are rarely free from a dull headache, pains at the spinous process of the lower cervical vertebra, and at the lower angles of the 52 FUNCTIONAL NERVOUS AFFECTIONS. scapula. Palpitation of tlie heart and general nervous irritability are also among tlie continuous symi)tonis. The history of the affection often goes back to the earliest recollections of the patient, and in nearly all cases a vast number of supposed remedies have been tried, sometimes with slight temporary relief, but more frequently without any good results. In a consider- able number of cases the affection is developed during school- days, a circumstance which has led to the ab- horrent supposition that it results mostly from impure thoughts and practices. Fortunately, this is a gross libel ujDon a class of humanity on the whole characterized by frankness and intelligence. If we remember that, at the age of from eight to fifteen, nearly all of the children in whom this affection is found are at school, closely pursued by examinations and a multitude of studies, we shall see that the demand upon the ocular muscles is excessive, and that this demand is for the most part made in crowded school-rooms, where the air is vitiated, and nerves and muscles are thereby rendered less capable of enduring the strain. Again, these subjects of mi- graine are, as a class, unusually ambitious, and such children maintain advanced positions in their classes at an expense of eye-strain even greater than that which attends the exercise of the eyes of the less am- bitious pupil. If, added to this, there is an anatomi- cal or physiological reason for unusual strain in doing the ordinary work of the eyes, we have a combination of circumstances conspiring against the strength of these children. MIGRAINE. 53 This is not only tlie more true but the more gen- erous explanation of the occurrence of these attacks, at this period of life, than the one alluded to ; and the author, after a careful investigation of both sides of this question, feels justified in earnestly protesting against the unjust insinuation. Some patients suffer less when absent from home, occupied in travel or repose, or when engaged upon light duties which permit them to be much in the open air. Tonic medicines also sometimes increase the intervals between the attacks and render them less severe. The temporary relief, however, which lengthens the intervals or modifies the attacks can not be regarded as a cure. And a cure can only be assumed when so long a period of time has elapsed since a last attack that, under ordinary circumstances, in the par- ticular case, a very large number of attacks could reasonably have been expected. Again, as in case of most functional nervous diseases, there is a tend- ency to a change in the form of the complaint, and one subject for several years to migraine may find that he has no longer sick-headaches, but is a sufferer from some form of neuralgia, perhaps equally dis- tressing with the former complaint. Such a case can not be regarded as cured. There has been simply a change in the manifestation of nervous irritation. In all these cases there is an underlying cause, which is to be found and removed. This accomplished, a per- manent cure may be anticipated. Here, as in the case of the more ordinary forms of headache, it will be found that ocular defects play a 54 FUNCTIONAL NERVOUS AFFECTIONS. conspicuous role as causative conditions in migraine. According to the experience of the author, these de- fects constitute by far the greatest factor in these cases. Unlike the ordinary forms of headache, how- ever, migraine does not so frequently yield to the simple measures of adapting glasses to correct re- fractive errors. There is often a complicated state of refractive trouble and muscular insufficiency, demand- ing greater care and judgment in correcting the ocular conditions. With sufficient accuracy in relieving these defects, however, sick-headaches will, in the great ma- jority of cases, cease. The following are not only typical cases of sick headaches, but are illustrations of the ordinary results of treatment directed to ocular defects in a great num- ber of cases : Miss N., aged seventeen. November, 1880. Had during the past three years suffered greatly from "blind headaches." She was delicate, anaemic, suffering from nervous irritability almost charac- teristic of chorea, and quite unable to endure ordi- nary physical exercise. Paroxysms of headache occurred once or twice a week, and lasted one or two days. The onset of the attack was uniformly marked by a total loss of one half the field of vision and enfeebled vision in the remaining half of both eyes. The hemiopia was heteronymous, the tem- poral portion of the field of each eye being lost. After half or three fourths of an hour of this visual disturbance, which was associated with pain over the eyes and through the orbits, and with a general MIGRAINE. 65 sense of chilliness, tlie orbital and frontal head- ache became most intense, nausea followed, and the patient was forced to retire to her bed in ex- treme torture and iDrostration. Vomiting usually occurred, but not uniformly. If she could fall asleep, a night's rest might bring relief, but the attacks not unfrequently continued until after the second night. During the period of visual disturbance of one of these attacks the eyes were examined, with the fol- lowing results: The field of vision was contracted in all directions, but more especially in the outer portion, as shown in the dia- gram which repre- sents the field of the right eye. Vision was f^, the letters of the trial-card appearing and disappearing. The ophthalmoscope showed the disc pale, the arteries rather small, the red cylinder of the larger being bordered with white lines representing the unusually conspicuous sheaths of these vessels. The veins were rather large. The general background lighted up well, but was of paler red than usual. The young lady's mother, who had died in child- FiG. 2. 56 FUNCTIONAL NERVOUS AFFECTIONS. birtli, had, during several years preceding the time of her death, suffered from chorea, and her father was a neurotic subject. No physical cause for these frequent and torturing nervous disturbances was found elsewhere than in the eyes and their appurtenances. She had a moderate degree of astigmatism, and very feeble adducting power. Cylindrical glasses were employed to correct the astigmatism, and the adducting power was developed by systematic exercise of the muscles, until complete associative action was established. After about three weeks the headaches ceased entirely, her strength im- proved rapidly, and she was soon in excellent health. In June following a slight return of the trouble caused her to direct renewed attention to the condition of the eyes, when it was found necessary to renew the exer- cise of the ocular muscles for a few days. Since that time she has continued well. Migraine not unfrequently alternates with intense neuralgic headaches in which nausea is absent, or the one form of trouble may replace the other perma- nently. Mrs. H., aged forty. February, 1879. Is an exceedingly active woman when well, but during nearly all her life has been subject to frequent and tormenting attacks of migraine, which during the past year have alternated with neuralgic head- aches. She rarely passes a week without being confined to her bed from one to three days. As soon as the attack of headache or neuralgia is over, she is ready to drive out, and almost compensates MIGRAINE. 57 by Iter unusual energy for the time lost in bed- She is, however, rarely without pain in the head and back, and often passes whole nights without sleep. She has also for many years had neuralgia in the eyes and face. The eyes being examined, she is found to have hypermetropia manifest, 1 Dioptry, and to have markedly insuflScient adduc- tive power. Convex glasses were prescribed and used, and the adducting power increased to the proper degree by exercise. The headaches and neuralgic troubles ceased when once this was accomplished, and during the sev- eral years intervening she has continued well. Many patients from distant cities, or even those residing in the vicinity, after making one or two calls may discontinue their visits and make no report of their progress. Necessarily, in such instances, noth- ing can be known of the result of advice given, or whether the advice has been accepted. Some of these transients, however, make their appearance after longer or shorter intervals, and the result of the single inter- view is first learned by the physician, perhaps, after several years. The following is an instance of this kind : Mr. J. F. de L., aged forty-five, consulted June 4, 1879, on account of sick-headaches of unusual intensity. Since early boyhood he has been sub- ject to attacks occurring with great frequency, the interval between attacks being rarely as much as four and more frequently not more than two days. He describes the paroxysms as follows : Pain com- mences in the temples and forehead, and becomes 68 FUNCTIONAL NERVOUS AFFECTIONS. more intense and general until nausea and vomiting set in, when he retires to his bed. His wife sj^ends the night in applying lotions and applications to his head, and bathing his feet in hot water. He is accustomed to take 1*5 gramme bromide of po- tassium with sulphate of morphia O'l centigramme combined, and repeated at intervals of one or two hours, with slight relief. The paroxysm, however, rarely continues less than twenty-four hours. He has spent much time in traveling in mild climates, hoping to gain relief, but has often returned worse than he went from home. He was found to have astigmatism, corrected by lenses of the following combination : Spher. 0*50 D., cylind. 1 D., axis 90°, which were advised for constant use. He was not seen again until June 28, 1883 (more than four years), when he called, saying that he had used the glasses prescribed, and had, during the four years, been almost entirely free from the tormenting affection which had followed him during a great por- tion of his life, but that within a few weeks he had suffered a few slight attacks. It was found that the spectacle-frames had become so bent as to give the cylinders an improper axis. The frames were bent into position, and the patient advised to observe care in keeping them so. Only two cases are given as additional illustrations, the first without dwelling upon details. Both are typical cases of sick-headache : Mrs. M., aged thirty-two. June 3, 1882. Dura- MIGRAINE. 59 tion fifteen years ; attacks about once a week. Eyes trained two weeks. October 7, 1883. Is in perfect health. Has not had attack of migraine since first week in June, 1882. No such respite has been kno^vn in past fifteen years. Miss Alice S. was brought by her physician, Dr. William Stevens, October 2, 1882. The patient is twenty-nine years of age. Is rather tall, of fine form, but thin in flesh and ex- tremely pale. The lips are colorless and the ocular conjunctiva of pearly white. She has had migraine once or twice a week during the past nine years. The pain is always unilateral, attacking one or other eye and supraorbital region, and extending downward along the course of the branches of the fifth nerve. With each attack she is forced to re- tire to her bed, and intense nausea and vomiting are always present. A night's sleep often brings relief. In this case there was found to exist compound myopic astigmatism (M. 3-50 D. + A M. 1*25 D), with insuflSiciency of the internal recti muscles 27°. Glasses for correcting the refractive error were pre- scribed, and tenotomy of one, and soon after of the other, external rectus was made, fully correcting the insufl3.ciency of the interni while maintaining full ab- ducting power. She has been seen from time to time, and careful observations have been made of the ocular conditions as well as of her general health. There continues 60 FUNCTIONAL NERVOUS AFFECTIONS. perfect adducting and abducting power, and the equi- librium test shows no insufficiency. Her health improved from the time of the opera- tions, the color returned to her face, she gained in weight and strength, and, although a year has passed, she has not had an attack of migraine. The results of treatment of migraine, by the re- moval of, or assistance to, ocular defects, have been no less successful than of the more ordinary forms of headaches by similar means ; but, as before intimated, migraine is frequently a manifestation of more com- plicated ocular conditions than the ordinary head- ache, and consequently greater care in discovering, and greater skill in removing, these defects may be demanded in this than in the more ordinary forms. It is a fact Avorthy of consideration that the most violent and characteristic symptoms of migraine are directly referable to the orbit or its immediate sur- roundings. "We may well suppose that the i3aroxysm repre- sents the last degree of perturbation of the nerves con- nected with the muscles of accommodation or of con- sensual movements, and that the pain in and about the eye and the intolerance of light are direct manifes- tations of this condition of incomi)lete surrender of their appropriate functions. NEUEALGIA. Passing, now, to the consideration of neuralgia, we shall find not only close relations with the forms of neuroses already discussed, but that difficulties in the NEURALGIA. 61 performance of the visnal act constitute an important causative factor. Before proceeding to discuss tlie tliera^Deutics of the disease, it will be well to determine, first, j)recisely w^hat is meant by the word as used in this essay, in or- der that there may be no misunderstanding as to the character of the cases which may be adduced. The word neuralgia (from vevpov, a nerve, and d\yo were used. Under this regime some improvement in the mental and physical condition could be observed after the first week. The fits, however, became more fre- quent and severe in proportion to her recovery from the influence of the drug. Thus, during the week ending May 3d there occurred flf teen fits, in each of which unconsciousness continued from ten to thirty minutes. During the week ending May 31st there 116 FUNCTIONAL NERVOUS AFFECTIONS. were twenty-nine very severe attacks, and attacks of jpetit mal in gi-eat numbers. By tlie 29 til of May, after almost daily trials, it was hoped that some progress had been made in the knowledge of the relations of the eyes, and it was supposed tliat an insufficiency of the externi of from 10° to 20° at twenty feet existed while using the convex glasses. With a clear understanding, on the part of the father of the girl, of the difficulties attending the determination of precise conditions under the cir- cumstances, and with his full approval, an opera- tion for insufficiency of the externi was made on the right eye, June 4th, and two days later a similar operation on the left, after which the appearance of the eyes was improved, and little if any insuffi- ciency was shown by the tests, such as could be made. June 1st, she had five lits. June 2d, she had seven fits ; and, June 3d, she had five. From June Uh (the day of the operation) to June lltth no attacks occurred. From June 14th to June 21st she had eight attacks. June 21st to June 28th, three attacks, all of which were unusually light. No -petit mal since June 4th. July 7th, she returned home, her last attack having occurred June 25th. The change in her mental condition had been since the operations truly marvelous, and her physical condition had equally imi^roved. The photograveurs, Figs. 1 and Q_ EPILEPSY. 117 2, Plate III, exhibit the changes of physiognomy which occurred during a single month. Fig. 1 is from a photograph taken Just preceding the first operation ; Fig. 2 is from one taken a month later. From time to time the patient has been seen. She continues in robust health and her intellect has returned. An attempt to send her to school, some months after her return home, was followed by a very slight relapse, but her friends were advised to wait a year before allowing her much close use of her eyes. A year after this her condition continued good with no return of the malady, and a year and a half after the operation, her physician wrote that she continued well. (I have heard, indirectly, just as this manuscript is about to be sent to press, that the girl has a renewal of her attacks. If so, she has, beyond a doubt, some remaining muscular disability, which may still be removed.)] * J. P., aged fourteen, April, 1883. Was fairly well, with the exception of an attack of pneumonia, until a year ago. Then had his first attack of epi- lepsy. During the year has had twelve severe at- tacks at intervals of about a month, and many at- tacks of petit mal. Examination of the eyes showed hypermetropia. Eight 2 D, left 2*25 D. Insufficiency of external recti 7°. Glasses for partial correction of hypermetropia were used, and on the 23d of April partial tenotomy of the internal rectus of the right eye was made, * Case introduced in present edition. 118 FUNCTIONAL NERVOUS AFFECTIONS. followed by a similar operation upon the internal rectus of tlie left on the 29th of April. May 1st, no insufficiency of the recti muscles is manifest. The last attack of epilepsy occurred April 20th, three days before the first tenotomy. He has been well, even in respect to petit mcd, more than seven months."^ G. S. G., July, 1883. During the past year has had quite a number of epileptic attacks, does not know exactly how many. Has a feeling of inde- finable nervousness, and his mind is so much affect- ed that he has been forced during the whole year to abandon his business, that of an apothecary. Has suffered much inconvenience during the past eight years from constipation. He has astigmatism corrected by, right eye 1 D cylindrical, axis 90° ; left eye 0'75 D cylindrical, axis 90°. There are also slight insufficiency of the exter- nal recti muscles and deficient adducting energy. The patient was advised to use correcting glass- es, and his eyes were exercised by means of prisms. No further attacks have occurred, the obstinate constipation is entirely relieved, and the patient writes, under date of November 21st, that he is quite well. [Miss M., aged twenty-nine. Subject to epilepsy and chorea from the first year of her life. Epilep- tic attacks occur from three to five times daily. Occasionally the fits are of great violence, but they * Nothing has been known concerning this patient since the above record was written in 1883. EPILEPSY. 119 usually last only a few minutes. She has never, since her first year, taken objects in her left hand, that side being most affected by chorea. The left elbow is drawn forward and strongly against the chest, the hand turned palm outward, backv^ard, and upward. The left arm, and in less degree the whole body, are in constant and violent motion. If an attempt is made to bring the arm into its normal position, the whole body becomes convulsed, the face distorted, and both arms move wildly. The visual anomalies were hyperopic astigmatism, right eye, 1*00 D; hyperopia, I'OO D, left; insufficiency of the externi, amounting to diplopia of 5° when red glass was used, and hyperphoria, 2°. The hy- perphoria and astigmatism were treated with cylin- dro-prismatic glasses. Tenotomy of one internus was done under great difficulties, owing to the patient's mental state, November 22, 1884, and of the other, January 3, 1885. Great relief followed the first operation, and the fits ceased from the 1st of December. In a month she was able to use the left hand for the first time in twenty-eight years to a considerable extent, and delighted in showing how she could brush the windows of the consulting-room with a napkin. Her intellect im- proved, and, as will be seen by the portraits (Figs. 1 and 2, Plate IV ; No. 1 taken November 17, 1884, No. 2, February 2, 1885), her head came to the nor- mal position, and her appearance in every respect was better. Up to April 20th, when the last rec- ord was made, there had been no return of epilepsy. 9 120 FUNCTIONAL NERVOUS AFFECTIONS. I have, however, learned that during the summer the fits returned in less frequency and degree. A recent letter from her sister informs me that it is the purpose of her friends to pursue the treatment which resulted so favorably still further as soon as circumstances allow.*] The statement of the cases given above demon- strates beyond a doubt that, in the treatment of epi- lepsy, examination of the conditions of the eyes is of sui)reme importance, and that with sufficient attention to this factor among causative influences tending to epilepsy, marked progress may be exx:)ected in its treat- ment. It is further to be remembered that relief obtained by removal of causes is radical, permitting a complete return to health ; while relief following the employ- ment of bromides is only such as is obtained by a pro- longed dulling of the nervous susceptibilities, and can only cure by this blunting process, which, even when resulting in any continued arrest of attacks, leaves the patient in a deplorable mental and physical condition. MENTAL DISORDERS. A process of irritation, so prolific of nervous dis- turbances as difficulties in performing the visual func- tion has been shown to be, must, in the nature of the case, react upon the mental as well as upon the senso- rial operations of the nervous system. It is not within the design of this essay to discuss the subject of mental alienation further than, in pass- * This case is not in original MS. MENTAL DISORDERS. 121 ing, to apply the principles already established to this department of investigation. Many instances of acute mania as well as of more chronic and less violent forms of mental disturbances have been known to recover in a manner truly surj^ris- ing, upon relief being afforded from some perplexity in the ocular operations. Thus, a young lady who had been a victim of acute mania three months, who had already spent two terms of eighteen months each in lunatic asylums, and who was known to have inadequate accommodative jDower, returned to her normal mental condition at once upon stimulating the accommodative muscles by eserine. A lady who had been a teacher and had worked very hard became the subject of hallucinations. She imagined herself a wheelbarrow, and that she was be- ing trundled about. She became at once incapacitated for any employment, and was, after some time, taken to a sanitarium, where she continued during nearly a year and a half. During this time the hallucination changed, and she imagined a face looking over her shoulder and into her own. If she was awake in the night the face was with her, and if she walked or rested it never left her. She was tormented with in- cessant and violent headache ; slejDt very poorly, and was too weak to endure any but the most trifling ex- ercise. She had insufficiency of the external recti muscles, which was relieved by operations u]Don the internal recti. On the morning following the first operation she 122 FUNCTIONAL NERVOUS AFFECTIONS. awoke without tlie presence of her demon, which has never returned ; with the second operation her head- ache disappeared, and she was within a few weeks in vigorous health. During more than a year she has provided for her- self by her own labor as a copyist, and has continued in excellent health."* This case is fairly representative of several others •which need not be related. [Plate y represents a most remarkable change in the condition of an insane young man. The history of the case is as follows : The patient was brought to me by his parents, who brought also a letter from Dr. P. M. Wise, Superintendent of the Willard Asylum for the In- sane. According to the history given by the parents at their first visit, October 12, 1886, the boy had been insane a year and ten months (according to the report of neighbors, much longer). During a sea- son of unusual religious interest the boy became un- questionably insane. His condition was gradually more and more hopeless until his friends determined to commit him to the asylum. It was when at this institution that they were advised by Dr. Wise to take the patient to New York. When first seen he was stolid, refusing to speak, and sadly demented. He wept aloud, and wrung his hands much of the time. He refused food, and, indeed, for many * The author is permitted to refer, in connection with this case, to Dr. R. Speakman, Wellesley, Mass. ; Dr. A. H. Allen, New London, Conn. ; and Dr. J. Blake Rohinson, New York. Ql MENTAL DISORDERS. 123 months had only taken it as it had been placed in Ms month by others. If standing, he held his arms ont in an imbecile manner with the fingers spread apart. The saliva flowed in streams from his mouth to the floor. He was thin and pale, and a cold moisture covered the skin. In this pitiable condi- tion it was difficult to obtain exact information of the ocular conditions, but by the exercise of much patience these conditions were sufficiently made out to enable a generally correct judgment to be formed. Under atropine he showed hyperopia 1"00 D, with insufficiency of the extern! 4°. On the 14th of Octo- ber the first photograph (Fig. 1) was taken, and on the same day a tenotomy of one of the internal recti was done, and two days later a similar operation was made on the opposite internus. From that day an improvement could be seen in the lad's mental state. Within a week he was so much improved as to amaze those who had seen him in his first condi- tion. He soon began to take food of his own ac- cord, and in two weeks he was in a fair way to com- plete recovery. On N'ovember 2d the second pho- tograph (Fig. 2) was taken, eighteen days after the first; and three weeks from the day of his first visit he returned to his home, no longer insane. His friends were advised to bring him again after a few weeks, which they wisely did. Slight hyper- phoria was then found, and a tenotomy of one of the superior recti was done. When he re- turned home the second time he was, so far as could be detected, perfectly well. 124 FUNCTIONAL NERVOUS AFFECTIONS. The photograplis show more than I am able to tell, but even they do not convey a perfect idea of the wonderful revolution which had taken place in the mental and physical condition of the boy in eighteen days].* [Plate YI is introduced here as representing one of the cases treated by attention to ocular conditions at the Willard Asylum for the Insane during the summer of 1886. Space does not permit of a history of any of these cases, but the photographs fairly rei)resent the average change of physiognomy in these people who had, during many years, been confined in an asy- lum].* It follows, then, that in mental troubles, also, the condition of the eyes should be carefully inspected, and sudden and gratifying relief will often reward at- tentions intelligently directed to any embarrassment which may hinder them in the performance of their offices. HEREDITY. Enough has been shown in the discussion of neu- ralgia to render it evident that to a certain extent the construction of the eyes constitutes an imi)ortant ele- ment in hereditary predisposition to neuroses. The orbit and its contents are facial features, which are, in their general form and relations to other parts of the face, characteristic in families. The resem- blances so strikingly exhibited in many families de- pend very largely upon the construction of this portion of the face. The form of the eyeball and the length * In present edition only. > HEEEDITY. 125 of the straight muscles are materially modified by the form of the orbit. A broad, flat face at once suggests to the oculist a hypermetropic eye. A narrow face, with prominent features, is more likely to be associ- ated with a lengthened eyeball, and, if the bones of the face are quite unlike on different sides, there is a presumption of astigmatism. With many exceptions, these general rules afford a tolerable estimate of the conditions of the eyes ; but with varying dej)ths of the orbit there must also be varying lengths of muscles. In many families a want of equilibrium of muscles is as characteristic a feature as hypermetropia or astig- matism. Thus in the family of case No. 91 of the table, at page 145, the patient had hypermetroj)ia, and had also converging strabismus. She had one brother and three sisters, all of whom were cross-eyed. Oculists often meet with such instances. Hence, the muscular balance of the eyes as well as their refractive condition enters largely into the composition of family simili- tudes. If, then, the eyes in certain families are, as facial features, generally too short, or if there is in the fam- ily a tendency to squint, even if the tendency is not manifest to the ordinary observer, there is imposed upon that family an inordinate task, either in accom- modating the eyes for near points or in maintaining paralMism of the visual lines. While the subjects of such defects are in full vigor, or while the parts sub- jected to the unusual demand are used but moderately, there may result little or no inconvenience. 126 FUNCTIONAL NERVOUS AFFECTIONS. There is under tliese circumstances sufficient nerv- ous energy to supply the ordinary draft upon the nervous system and to perform this extra task ; but if other excessive calls upon the nervous energy are made and the surplus vigor is expended, the difficult task of adjustment or of accommodation can no longer be per- formed without manifestations of nervous exhaustion. Hence, so long as no assistance is rendered to these overtasked muscles, disease or nervous i^rostration arising from their disability is exceedingly chronic, and long periods of rest with tonic medicines are required in order that a sufficient amount of reserve energy may be acquired to perform their function and also the requirements of active life. The same nervous irritation does not always react in the same manner. This is well shown in Brown- Sequard's experiments in tickling. One subject laughs, another cries, a third has contortions of the limbs, and the fourth tetanic rigidity of the muscles. In case of irritation from difficult accommodation from refractive anomalies or excitation from muscular insufficiencies, family characteristics, such as hyper- metrojDia or insufficiency of the externi, for instance, react in various ways. One member of a family suf- fers from migraine, another from chorea, and a third from neurasthenia. Again, in one such family the neuropathic tendency consists in eyes of insufficient length, while in another family the tendency may originate in a want of equilibrium of muscles. Thus the various forms of features, when deviating from an ideal standard of anatomical perfection, may give HEREDITY. 127 rise to a great variety of anomalous conditions of the eyes. It is very generally supposed that nervous diseases prevail to a greater extent in our own times than for- merly. Should this prove to be true, which is quite likely, it is interesting to consider, in connection with this supposed increase of nervous troubles, the fact that at the present time the eyes are j)re-eminently the working organs of the body. When the amount of voluntary effort of the mus- cles of accommodation and adjustment of the eyes de- manded by the exigencies of modem civilization from all but the most unskilled class of laborers is consid- ered, it must be seen that in this may be found an explanation of any increased tendency to nervous dis- eases. In several hundred instances the history of diseases to which members of families have been subjected has been ascertained with as much accuracy as possible. In a certain proportion the history has been obtained through several generations, but, as it is in most cases impossible to obtain any history beyond immediate relatives, efforts were principally directed to obtain a record of the present condition of parents, brothers, and sisters, if living, and of the cause of death if not living. It is unnecessary to occupy the space which would be required to exhibit all this research, and a table is appended to this essay in which is shown the results of the inquiry in one hundred cases which are con- secutive with certain exceptions here explained. The cases chosen are all cases in which a specified 128 FUNCTIONAL NERVOUS AFFECTIONS. form of nervous disease existed and from whicli the I)atient was seeking relief. All cases of simple myopia or cases in which the refractive error is less than 1 D, and all cases of simple muscular insufficiency have been rejected from the list. Myoi^ia is a variable condition, and may arise from other anomalous forms of refraction. Slight refractive errors may or may not be the expression of a family characteristic ; and muscular insufficiencies may often result from refractive errors. Hence all these cases, in which the hereditary influence is questionable, are left out. The list, then, contains consecutive cases of nervous diseases in which the family record has been ascer- tained, and in which refractive errors of 1 D or more, excluding cases of simjole myopia, have been found. The exclusion of muscular insufficiencies appears necessary, and yet unfortunate ; for, while these con- ditions are often acquired they are also not unfre- quently hereditary, as has been shown. The list of cases consists of adults, the ages rang- ing from seventeen to sixty-four years, and the family record contains none but immediate relatives — ^parents, brothers, and sisters. In order to avoid complications which might arise from including the diseases incident to childhood, and especially as there is often a want of knowledge on the part of those of whom inquiry is made as to the nature of disease from which infant brothers or sisters may have died, all children under the age of twelve years have been excluded from the family record. HEREDITY. 129 We have thus a fair representation of the classes of disease to which families, in which refractive errors prevail, are subject. It will be seen that chronic nervous diseases prevail in nearly all these families, and it should be remarked, in passing, that in family records in which neuralgia, headaches, and other nervous troubles are said to ex- ist, it is in every instance to be understood that the disease is chronic, one to which the person is habitual- ly subject ; and occasional or temporary ailments are in no case included. Tliere appear in this table fevers and other acute diseases, but by far the greatest proportion of deaths has occurred either from very chronic complaints or from sudden strokes like apoplexy or diseases of the heart. If it is remembered that cerebral apoplexy is often the result of an atheromatous condition of the arteries, and that death from heart-disease, although occurring suddenly, is often the result of old lesions, the list of mortality from continued causes is in- creased. The cause of death most frequently noticed is con- sumption, there being, among two hundred and seven deaths in these families, eighty-nine from this cause. Consumption is, in the death register of every city, an important item. Among the deaths of persons more than ten years of age in the city in which these records were made, in years in which no epidemic prevailed, less than twenty- five per cent were attributed to consumption. In these families in which considerable refractive errors 130 FUNCTIONAL NERVOUS AFFECTIONS. prevail the iDroportioii is mucli greater, being no less than forty-three per cent. In the same city the average proportion of deaths from Bright' s disease is about four per cent, while in this list about seven per cent have died of that dis- ease. Paralysis and apoplexy constitute five per cent of the death-rate of the city, while in the table the pro- portion from these diseases is nine per cent. A careful study of this record of disease in families with high degree of refractive errors must impress every thoughtful student with the following important truths : 1. In such families there is an extraordinary preva- lence of nervous disorders, including migraine, neu- ralgia, insanity, and organic lesions, such as apoi)lexy and paralysis. 2. That consumption and Bright' s disease are rife in these families. 3. That the higher the grade of refractive anomalies, the greater is the proportion of these last-named dis- eases. It can not fail to occur to one who compares this table with the facts given in this essay that families in which such features are transmitted are subjected to unusual nerA'ous tension in respect to a most important function, and that this waste of nervous energy in per- forming an ordinary task renders the members of such families easily subject to chronic irritations of impor- tant organs not necessarily in the immediate vicinity of the seat of the loss of power. Hence, again, such HEEEDITY. 131 complaints as pulmonary consumption are but little amenable to medical treatment for the reason tliat the primary cause continues. If the patient with phthisis is found also to be the subject of a marked refractive anomaly or of pro- nounced insufficiency of the recti muscles, his chances of recovery under medical treatment must be greatly enhanced by relieving him of these unnecessary bur- dens. Again, in families predisjDosed to diseases of this class it must be evident that much may be done to avoid them by relieving the unfavorable conditions which may otherwise lead to disease. THE TREATMENT OF NERVOUS DISEASES. From what has gone before, it follows as a neces- sary conclusion that attention to ocular conditions should occupy a prominent place in the treatment of nervous disease. In the series of cases upon which the conclusions arrived at in this essay have been based, the use of drugs has been almost entirely excluded. In rare cases medicines for relief of temporary symptoms have been administered, but it can not be said that the re- sults, even in these exceptional cases, have been to any considerable extent attained by means of drugs. Nevertheless, it can not be questioned that medi- cines which act as tonics or in various ways tend to the promotion of general vigor must be valuable. In the same manner, rest and change of air and scene are known to exert influences favorable to the temporary 132 FUNCTIONAL NEEVOUS AFFECTIONS. relief of almost every form of neurosis ; mental emo- tions of a pleasing character and the influence of hope and courage are all powerful auxiliaries in the treat- ment of this class of complaints. All these facts are too familiar to need more than a passing acknowledgment of their value. If these means have been, to a certain extent, ig- nored in the treatment of these cases, it has been in the conscientious hope that by confining the efforts strictly to what, in such cases, has been supposed to be the primary cause, less of doubt in regard to the re- sults of treatment, and as to the nature of the difficul- ties which it was hoped to remove, must exist. In this connection the teachings of the illustrious Graefe in regard to asthenopia are extremely appro- priate. Speaking of spontaneous cures, and of cures by cer- tain measures not radical, he says:* "In these cases of temporary asthenopia, fresh air, cold water, tonic medicines, and electricity are indicated. "What disap- pears under such treatment is only the symptoms of asthenopia, while the disturbance of the equilibrium of the antagonistic muscles remains and the least sinking of energy recalls the former difficulties." In like manner neuralgia, chorea, and other nerv- ous difficulties may disappear under similar treat- ment, but it is the pain or irregular nervous action which has disappeared while the essential difficulty may remain. Leaving, then, the discussion of these means, so * " Archiv fur Ophthalmologie," Band 8, II, 346. TREATMENT. I33 familiar to all, some points in regard to the removal of causes may be briefly stated. Although so large a pro- portion of cases find their origin in ocular conditions, the search for irritating causes should by no means be confined to that class of influences. The state of the ear, carious condition of the teeth, the constriction of a passage, even of one so small as the nasal duct, all may act as permanent or primary causes of disease. One instance has been cited above where the removal of a mass of cerumen from the ear has been followed by immediate relief from a long-continued and severe neuralgic affection. Several instances of relief from nervous affections by the dilatation of constricted pas- sages might be given, and the relief sometimes ob- tained from the removal of decayed teeth is familiar. Respecting the corrections of ocular defects, so little has been left by the illustrious masters Bonders and Graefe and by other learned ophthalmologists that little need be said here, except to ask some considera- tion for a few points which have received less attention than their merits would justify. The use of prisms for gymnastic exercise has been frequently mentioned in these pages. Too many happy results have followed the use of this simple method for increasing the tone of the ocular muscles, to leave a doubt of its eminent value. In cases of slight difference in the refractive con- dition of the eyes, as, for instance, a very low degree of astigmatism of one eye and emmetropia of the other, there frequently arises, for reasons which need not be discussed here, a want of comj)lete adducting or 134 FUNCTIONAL NEEVOUS AFFECTIONS. abducting power, or of botli, whicli may not depend upon any very considerable degree of insufficiency of the ocular muscles, such as might be demonstrated by the equilibrium test at six metres, yet this deficient power for easy co-operation of the eyes is an important factor in asthenopic and other nervous symptoms. By causing the patient to look at an object placed at a distance of six metres, directing him to avoid di- plopia by the action of the adducting or abducting mus- cles, as the case may demand, while prisms of gradu- ally increasing strength are placed before the eyes, these muscles are separated in their action from the action of the accommodation and the increased ability to adduct or abduct, soon shows the increase of tone of the muscles. In the text-books on ophthalmology the subject of insufficiency of the internal recti muscles is discussed, and some of its results were shown, with directions for treatment. The subject of insufficiency of the exter- nal recti, however, has been almost wholly ignored. Graefe, indeed, refers to this subject,* and says that he has performed tenotomy of the internal recti on two occasions. He seems, however, not to have met with signal success, for he declares that the method remains more interesting than practical in comparison with the more peaceful choice of specta- cles. A few other attempts have been made in this direc- tion, but the result of all seems to have been the drop- ping of the subject by universal consent. * " Archiv fur Ophthalmologie," Band 8, II, 321. TEEATMENT. 135 That insufficiency of the external recti muscles is a condition equally or more perplexing in the function of adjustments of the eyes than insufficiency of the in- ternal recti, the author of these pages can not doubt. The effects, however, are less immediate. The patient affected with insufficiency of the internal recti rises, perhaps, from the perusal of a book with aching eyes ; but the subject of insufficiency of the externi may re- turn from the opera or other assembly where the eyes have been held fixed upon distant objects, to suffer from migraine on the following day. ISTeurasthenia, chronic headaches, hallucinations, vertigo, and insom- nia are among the frequent results of insufficiency of the external recti. Three hundred and fifteen operations for the relief of insufficiency of the external recti have been made by the author in cases where no converging strabismus existed. In each case patients were able to maintain and were accustomed to maintain binocular vision, but at an expense of greater than the normal effort. The operation is performed by bringing the tendon forward by means of a hook, as in the operation for strabismus, when the central fibers are divided at the sclera, allowing the borders of the tendon and the attachments of the capsule to remain uncut. The operation demands careful judgment and much delicacy of manipulation on the part of the surgeon. The custom of introducing a blade of the scissors be- neath the tendon and cutting down upon it, as in op- erations for strabismus, can not be safely followed in these cases. The division through the conjunctiva is 10 136 FUNCTIONAL NERVOUS AFFECTIONS. made exactly over the insertion of the tendon, and about one fourth of an inch in extent. The point of a fine blunt-hook is then introduced very exactly at the tendinous insertion, and the latter is put upon the stretch. A pair of blunt-pointed scissors then cuts down between the hook and the sclera, dividing care- fully each way from the center by several little cuts. The capsular connection at the borders of the tendon must, in all cases, be preserved. The insertion of the tendon is somewhat fan-shaped. By dividing all but the extreme fibers at the borders, the tendon lengthens slightly, while the division of the external fibers leav- ing a central band, as has been proposed by some who have suggested partial tenotomy of the externi in cases of insufiiciency of the intemi, results in very little, if any, extension of the tendon. The advantage of the operation proposed and prac- ticed by myself is, that by means of the extreme outer fibers of the tendon, or where greater relaxation is required, by means of the close connection of the capsule to the outer fibers, a considerable relaxation may be obtained, while the muscle is not allowed to fall back, as it is in the operation for strabismus. The operation can be performed in all essential i)articulars without the aid of the hook, a fine mouse-tooth forceps being made to seize the tendon at its insertion, while the scissors by successive cuts made perpendicular to the sclera divide it exactly at the insertion. Relaxation of the desired extent has by this means always been obtained, but the relief to the insufficiency is not always permanent, for the healing process is TREATMENT. I37 sometimes attended with a degree of contraction nearly or fully equal to the advantage gained by the opera- tion, in which case a renewal of the operation upon the same or the opposite eye may be made. The results have been extremely satisfactory, al- though, as might have been expected, in attempting a process in surgery which was practically new and be- fore tried only with the most doubtful, if any success, some difficulties have attended the accomplishment of the end, more especially in the earlier cases. Whatever difficulties may have been encountered, however, have been insignificant when compared with the notable and even surprising advantages resulting in the great majority of instances. It is not too much to say that the attending disad- vantages are less in this than in almost any operation in surgery from which results in any degree commen- surate can be expected. The use of the extract of calabar bean or of the sulphate of eserine applied to the eyes in cases of de- ficient accommodative energy is often of great tempo- rary benefit in a variety of nervous conditions. In- stances have been shown in the foregoing pages in which the nse of this agent has been followed by the happiest results, and many more might be given. In cases in which the tension of accommodation is extreme, the use of atropia applied to the eyes is often followed by immediate relief to nervous symptoms and by removing a chronic condition of tension may, in some instances, effect a ]permanent relief. The researches of a class of scientific observers, of 138 FUNCTIONAL NERVOUS AFFECTIONS. whom Cohn may be justly regarded as the leader, have shown how prevalent among children attending schools are found anomalies of refraction of the eyes. As the work of these children is to be performed principally with these organs, is it not simple justice to them that the function to be most employed should be enabled to be used with the least possible diffi- culty 1 Children are sent to school with the most complete ignorance on the part of parents and teachers of de- fects which may demand, on the part of the little ones, great expenditure of nervous force, and they are re- quired to keep apace with those who enter upon the same work with no such incumbrance. If they fail to perform the task of accommodating and of adjusting the eyes, and at the same time of maintaining their positions in their classes, they are condemned as idle or stupid. If, on the other hand, by virtue of great persistence and determination, they succeed in keeping abreast of their more fortunate companions, they perform their task at the expense of vital energies, and often lay the foundations for future disease. If it were required that the eyes of children should be examined before entering schools, and if the indications shown by such examinations should be observed, an infinite amount of suffering might doubtless be avoided. And should the custom of giving careful and intelligent attention to the conditions of the eyes become general, there can be no doubt that the prevalence of disease of the nerv- ous centers would undergo a marvelous reduction. TABLE Containing tJie records of diseases in the families of one hundred 2yatients suffering from nervous comjylaints, and in ichom marked errors of refraction have been found. The table includes successive cases beticeen the ages of four- teen and sixty-four, stating the age of the patient, the com- plaint for which he or she was treated, the refractive con- dition, the result of treatment so far as it is known, with the physical condition of the living, and the cause of death of those not living, xohen known, of parents, brothers, and sisters. TSo. Age of patient. Nature of complaint. 1 46 Head- aches. 2 38 Neural- gia. 3 41 Migraine. 4 5 30 55 Head- aches. Neural- gia. 6 37 Neural- 1 31 gia. Insom- nia. Eefractive error. H. 2-75. As. 1-00. H. 1-25. Ah. 1.00. n. 2-00. Ah. 1-00. Ah. 1-25. Kesult of treatment. Cured. Cured. Cured. Cured. Cured. Not known. Cured. Family history. Father died of acute disease ; moth- er well ; one brother has neuras- thenia. Father died of cholera; mother died of cholera ; one brother died of fever ; one sister died of con- sumption ; two sisters well ; one brother well. Father died of acute disease ; moth- er has paralysis ; two brothers died of Bright's disease ; two brothers well; two sisters have nervous diseases. Father well ; mother well ; two sis- ters have chronic neuralgia. Father died of consumption ; moth- er died of paralysis ; no brothers or sisters. Father died of paralysis; mother well ; four brothers well. Father died insane ; mother has had hemiplegia; three brothers well ; one sister well. 140 FUNCTIONAL NERVOUS AFFECTIONS. No. Age of Nature of Eefractive Eesult of patient. complaint. error. treatment. Family history. 8 41 Neuras- H. 5-00. Not Father died of apoplexy; mother thenia. known. well ; one brother well ; one brother and three sisters died of consumption; one sister died, cause unknown. 9 30 Head- aches. H. 2-7.5. Cured Father died of Bright's disease ; mother well ; one brother has pa- ralysis ; one brother well ; two sisters nervous invalids ; one sis- ter well. 10 42 Neural- n. 1-23. Not Father died, cause unknown ; moth- gia. As. -50. known. er has headaches ; one brother died of disease of brain ; one brother died of heart-disease ; one brother died of consumption ; one brother well. 11 45 Epilepsy. H. 1-50. Not known. Father died of pleuritis; mother died of cancer; two brothers died of consumption ; one sister well. 12 40 Neural- gia, pa- ralysis. H. 2-00. Cured. Father died of pneumonia ; mother died of consumption; one sister died of consumption. 13 48 Neural- gia. n. 1-75. Cured. Father died of fever ; mother died in child-birth ; one brother is an epileptic ; one brother well ; one sister has rheumatism ; one sister well. 14 26 Epilepsy. H. 300. Not Father has rheumatism ; mother As. 2-00. known. died of Brij^ht's disease; one brother died from accident ; one brother has consumption; two brothers well ; one sister well. 15 51 Epilepsy. n. 1-25. Not known. Father well; mother died of con- sumption; one brother well; one sister has Bright's disease; one sister well. 16 41 Head- aches. n. 200. Cured. Father died of consumption ; moth- er has rheumatism ; two brothers died of consumption. 11 52 Head- n. 2 25. Not Father died of fever ; mother died aches. cured. of consumption ; one brother died of consumption ; one brother well ; one sister died of consumption ; one sister has consumption. 18 24 Neural- gia. H. 2-75. Cured. Father died of cerebral disease ; mother well ; three sisters well ; three brothers well. 19 48 Neural- n. 100. Not Father died of cerebral disease ; gia. treated. mother died of paralysis ; one sis- ter died of apoplexy ; one sister died of consumption. TABLE. 141 Age of patient. Nature of complaint. 43 Neural- gia. 43 Vertigo. 51 Head- aches. 51 Vertigo. 52 Head- aches. 58 Neuras- thenia. 40 Neural- 31 gia. Neural- gia. 34 Neural- gia. 40 Neural- gia. 64 Head- aches. 53 Head- aches. 30 Neuras- thenia. Kefractive error. H. 1-25. H. 1-25. H. 2-75. H. 2-50. H. 1-75. H. 2-00. H. 1-25. As. 1-50. Ah. 2-00. Ah. I -00. H. 1-25. As. 1-50. H. 1-25. Eesult of treatment. Cured. Not treated. Cured. Cured. Cured. Not treated. Improved Cured. Cured. Cured. Cured. Cured. Cured. Family history. Father has neuralgia ; mother well ; three brothers have neuralgia ; one sister has neuralgia. Father well ; mother has rheuma- tism ; one brother well ; one sister has vertigo ; one sister has I'hcumatism ; one sister well. Father died of pneumonia ; mother well ; one brother has headaches ; one brother well ; one sister has rheumatism ; one sister has some nervous disease ; one sister died of consumption. Father died of consumption ; moth- er died of — ; one brother has neuralgia ; one sister has neural- gia. Father died of consumption ; moth- er died of consumption ; one sis- ter has asthma. Father died of rheumatism ; moth- er died of fever; six brothers well ; one sister has consump- tion. Father died of epilepsy ; mother has migraine. Father died of acute disease ; moth- er subject to neuralgia ; one sis- ter has consumption; one sister has neuralgia. Father subject to migraine ; mother well ; four brothers well ; one sister well. Father died of apoplexy ; mother has neuralgia; one brother died of consumption ; one brother has consumption ; one sister a nervous invalid. Father died of paralysis ; mother of pleuritis ; one brother of con- sumption ; one brother of some nervous disease ; one sister has neurasthenia; one sister died of rheumatism ; one sister died of paralysis. Father not well ; mother has can- cer ; one brother well ; one sister well. Father died of accident; mother died of paralysis ; one brother well ; one sister well. 142 FUNCTIONAL NERVOUS AFFECTIONS. No. Ape of patient. Nature of complaint. Kefractive error. Kesult of treatment. Family history. 33 38 Neural- gia. H. 2-50. Cured. Father died of heart-disease ; moth- er has neuralgia ; one sister has rheumatism ; one sister has some nervous disease. 34 42 Neural- Ah. 1-00. Not Father well ; mother well ; two gia. treated. brothers have migraine; one ♦brother has neuralgia ; one broth- er died of chorea; one died of dysentery. 35 30 Head- aches. Ah. 1-50. Improved Father died of consumption ; mother well ; three sisters not well. 36 61 Insom- H. 5-00. Not Father died of abscess ; mother died nia. treated. of consumption; two brothers died of consumption; one sister died of consumption. 37 28 Head- aches. H. 1-50. Cured. Father well ; mother died of con- sumption; one brother died of consumption; one brother well; two sisters well. 38 45 Neural- Ah. 1-25. Not Father died of consumption ; mother gia. treated. died of cancer; no brothers or sisters. 89 24 Neural- H. 2-75. Not Father has nervous disease ; mother gia. treated. has neuralgia; one brother in- sane; one brother has chronic neuralgia ; one brother well. 40 51 Head- H. 1-76. Not Father died of fever ; mother died aches. treated. of consumption ; three sisters died of consumption ; one brother well. 41 35 Epilepsy. H. 2-50. Improved Father well ; mother has glaucoma. 42 40 Neural- U. TOO. Not Father died of consumption ; mother gia. treated. died of — ; one brother died of heart-disease ; one brother died of — ; one brother well ; two sis- ters well. 43 28 Head- aches. As. 7-00. Cured. Father well; mother has rheuma- tism ; one brother has consump- tion ; five sisters well. 44 61 Head- aches. H. 2-25. Cured. Father died of fever ; mother died of consumption ; four sisters died of consumption. 45 49 Head- As. 4-00. Not Father died of consumption ; moth- aches. treated. er died of consumption ; one sis- ter well. 46 26 Neural- gia. H. 3-50. Cured. Father died of Brigrht's disease; mother has neuralgia ; two broth- ers well. 47 53 Neural- Am. 1-50. Not Father died of old age ; mother died gia. treated. of Bright's disease ; one brother of erysipelas ; one sister insane ; one sister well. TABLE. 143 No. Afre of Nature of Eefractive Eesult of patient. complaint. error. treatment. Family history. 48 52 Melan- H. 1-00. Not Father died of accident; mother cholia. treated. died of jaundice ; one brother died of fever ; one brother well. 49 42 Neuras- thenia. As. 1-00. Cured. Father died of consumption ; mother well; one brother died of con- sumption ; one brother well ; four sisters died of consumption; three sisters well. 60 32 Chorea. E. 1-00. Not cured. Father has chorea ; mother well ; one sister has chorea ; one broth- er has chorea. 51 42 Spinal ir- ritation. H. 2-75. Cured. Father died of fever ; mother well ; no brothers or sisters. 52 52 Neural- gia. H. 1-50. Cured. Father died of Bright's disease ; mother died of Bright's disease ; three brothers well. 53 46 Neural- n. 1-25. Not Father died of apoplexy ; mother gia. known. died of angina pectoris; one brother died of consumption. 54 30 Head- H. 2-00. Cured. Father died of consumption ; mother aches. As. 1-00. died of cholera ; one brother died of fever; one brother well; one sister has pulmonary disease. 55 44 Mijraine. Am. 2-00. Cured. Father died of consumption ; mother died insane; one sister has chronic neurasthenia. 56 30 Chorea. H. 1-25. Cured. Father well ; mother well ; one broth- er has asthma ; one brother well. 57 44 Migraine. H. 3-00. Cured. Father died of consumption ; mother died of consumption ; one brother died of consumption ; one sister died of consumption; one sister died of paralysis. 58 47 Insom- H. 1-50. Not Father died of paralysis; mother nia. knovni. died of cancer; one sister has neuralgia ; one sister died of some nervous disease. 59 40 Neuras- thenia. Ah. 1-25. Cured. Father died of cause unknown; mother died of consumption; one brother died of consumption ; one sister has neurasthenia. 60 27 Head- aches. H. 3.50. Cured. Father died of apoplexy; mother well ; one brother well ; one sister well ; one sister has migraine. 61 37 Insane. H. 1-00. Cured. Father has neuralgia ; mother died of apoplexy ; two brothers well. 62 54 Neural- gia. H. 2-50. Cured. Father died of old age ; mother died of consumption ; two sisters died of consumption ; one sister well ; two brothers well. 63 32 Muscular spasm. H. 1-50. Cured. Father well; mother has consump- tion ; one brother well. 144 FUNCTIONAL NERVOUS AFFECTIONS. Ko. Age of patient. Nature of complaint. 64 28 Head- aches. 65 19 Head- aches. 66 37 Head- aches. 67 52 Head- aches. 68 43 Head- aches. 69 52 Head- aches. 70 52 Migraine. 11 42 Migraine. 72 18 Chorea. 73 42 Spinal ir- ritation. 74 14 Epilepsy. 75 61 Vertigo. 76 52 Head- aches. Kefractive error. H. 3-00. Ah. 1-00. H. 1-25. H. 2oO. H. 1-00. n. 2-25. H. 2-25. H. 1-25. H. 4-00. H. 1-25. H. 2-50. H. 2-25. H. 2-25, H. 1-75. Eesult of treatment. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Cured. Family historj'. Father died of consumption ; mother well ; one brother well ; one sister well. Father well ; mother has neuralgia ; one brother has chorea; one brother well. Father died of Bright's disease; mother well ; one brother died of pneumonia ; one brother has heart disease ; three sisters are invalids. Father died of Bright's disease ; mother died of aneurism; one brother died of consumption ; one brother well. Father died of paralysis; mother died of epilepsy ; one brother died of heart-disease ; one brother has locomotor ataxy ; one brother has chronic headache ; one sister died of some nervous disease ; one si.s- ter well. Father died of fever ; mother well ; two sisters died of fever ; two sis- ters well ; two brothers well. Father died of consumption ; mother died of acute disease; one brother died of fever ; one brother has nervous disease ; one sister died of consumption; two sisters died of cerebral disease ; one si.stcr well. Father died of heart-disease ; moth- er died of paralysis ; one brother died insane ; one brother well ; one sister died of tetanus ; one sister died of consumption. Father well ; mother died of Bright's disease ; two brothers well ; one sister not well. Father died of disease of heart; mother died of cerebro-spinal meningitis ; one sister died in- sane; one sister was insane; one sister died of locomotor ataxy. Father died of Bright's disease ; mother well ; one brother has headaches. Father died of consumption ; mother died of — ; one brother has neu- ralgia : one sister has neuralgia. Father died of consumption ; mother died of consumption; one sister has asthma. TABLE. 145 No. Age of Nature of Eefractive Result of patient. complaint. error. treatment. Family history. 11 40 Neuras- n. 1-75. Not Father died of apoplexy; mother thenia. treated. died of consumption ; one brother died of fever ; one brother well ; two sisters well. IS 45 Migraine. Am. l-7o. Cured. Father died of consumption ; mother died of consumption ; one brother well ; five sisters all have migraine. 19 51 Neural- gia. H. 1-25. Cured. Father died of heart-disease ; moth- er died of heart-disease; one brother died of — ; one sister died of — . 80 44 Neuras- H. 1-00. Cured. Father died of apoplexy; mother thenia. As. 0-50. died of consumption ; two brothers well ; one sister well. 81 56 Head- aches. H. 1-75. Cured. Father died of pneumonia ; mother died of cancer ; two brothers well ; one sister well. 82 37 Neural- gia. n. 1-00. Cured. Father died of — ; mother has neu- ralgia ; one sister has neuralgia. 83 24 Head- aches. Am. 16. Cured. Father has migraine ; mother died of acute disease ; one sister died of fever ; three brothers well. 84 31 Neural- H. 0-50. Cured. Father died of angina pectoris; gia. As. 1-00. mother well ; one brother died in- sane. 85 40 Spinal ir- ritation. Ah. 1-00. Cured. Father died of spinal disease ; moth- er died of consumption ; one sis- ter well. 86 20 Neural- M. 4-00. Cured. Father died of pneumonia ; mother gia. Am. 1-50. has neuralgia ; no brothers or sis- ters. 87 19 Neural- Ah. 1-75. Not Father died of pneumonia ; mother gia. known. has migraine ; five brothers well ; one sister has migraine ; one sis- ter well. 88 30 Neural- gia. H. 1-00. Cured. Father has asthma ; mother died of consumption ; five sisters well. 89 21 Head- aches. Am. 1-00. Cured. Father well ; mother has headaches ; one brother well. 90 17 Head- M. 5-00. Not Father died of consumption ; mother aches. Am. 1-00. known. died of consumption ; two brothers well ; one sister has migraine. 91 27 Neural- H. 1-50. Not Father died of consumption; one gia. known. sister has migraine; two sisters well ; one brother well ; the pa- tient, the brother, and the three sisters all have strabismus. 92 43 Neural- H. 1-25. Not Father died of heart-disease ; mother gia. known. has rheumatism ; two brothers died of consumption ; four sisters died of consumption ; one brother well ; two sisters well. 146 FUNCTIONAL NERVOUS AFFECTIONS. No. Age of patient. Nature of complaint. Refractive enor. Result of treatment. Family history. 93 27 Neural- M. 4-50. Cured, Father has rheumatism ; mother has gia. As. 1-25. migramc. 94 37 Head- H. 1-75. Not Father well ; mother has consump- aches. known. tion ; one sister well. 95 40 Neuras- thenia. As. 2-00. Father well ; mother died of apo- plexy ; one brother died of con- sumption ; two brothers well ; two sisters well ; one sister an invalid. 96 21 Head- aches. As. 1-00. Cured. Father died of Bright's disease; mother well ; one sister has neu- rasthenia ; one sister well. 97 48 Neural- gia. n. 3-00. Cured. Father died of abscess of the liver ; mother died of consumption ; four sisters well. 98 21 Head- aches. As. 6-00. Cured. Father has phthisis ; mother an in- valid; one brother died of con- sumption ; one sister died of con- sumption ; one brother well. 99 41 Neural- H. 4-50. Not Father died of apoplexv; mother gia. known. well; one brother died of acute disease ; one brother died of con- sumption; three sisters died of consumption; one sister an in- valid. 100 24 Neural- gia. H. 1-75. Cured. Father died of heart-disease ; moth- er well ; three brothers well ; two sisters well. Summary of the above Table. Average age (the minimum being fourteen) 39 Average refractive error 2'16 Number treated in which results were known 72 Important relief obtained among these from measures directed to ocu- lar conditions in i f>7 Deaths among parents 129 From acute diseases 26 " cerebrospinal diseases, epilepsy, chorea, insanity, apoplexy, etc 28 " consumption 39 " Bright's disease 14 " heart-disease and rheumatism 7 " miscellaneous and unknown causes 15 Parents living 70 Reported to be in good health 35 Suffering from nervous disorders 21 " " consumption 3 " " rheumatism 6 " " miscellaneous disorders 5 TABLE. 147 Deaths among brothers and sisters From cerebro-spinal diseases 14 " consumption 55 " Bright's disease 2 " acute diseases I3 " heart-disease and rheumatism 4 " unknown causes 2 Brothers and sisters living Reported well 148 Suffering from nervous diseases 51 " " consumption 7 " " Bright's disease 1 " " heart-disease and rheumatism 5 " " invalidism 9 90 221 SUPPLEMENT. If the doctrines set forth in this work are worthy of acceptance, it must follow that a knowledge of the refractive and muscular anomalies of the eyes is essen- tial to the most successful treatment of a very large proportion of nervous complaints. The supplemental portion of this work is prepared with the view of af- fording the practitioner who does not profess to be a specialist in eye-affections, a general understanding of the anomalies to be sought for and the means for their correction. No effort is here made to present an exhaustive or a critical treatise. One who would pur- sue these subjects in a technical manner will find abundant material for study in a part of this field in the superb works of Bonders and of Landolt ui)on "The Refraction and Accommodation of the Eye." Unfortunately, there are no text-books in which that class of anomalies of the ocular muscle known as " in- sufficiencies," is fully discussed. For the most part, the literature of this subject is confined to a single condition of "insufficiency," and even this receives, as a rule, but a passing notice. The reader will, in the pages devoted to this subject, find it treated very SUPPLEMENT. I49 briefly, but it is hoped that this little treatise will enable any intelligent practitioner to form correct con- clusions resiDecting the condition of the eyes of his patients in this respect. EEFEACTIOIS' AND ACCOMMODATION OF THE EYE. The eye may be regarded as an optical instrument, similar, in some respects, to a camera- obscura, such as is used by photograi^hers, in which rays of light are concentrated by means of convex lenses in such man- ner as to fall upon a screen at the rear of the dark chamber. If the screen is of white ground glass, an image of an object from which the rays emanate may be seen upon the glass by an observer looking from behind the screen. In the eye, rays of light pass through transj)ar- ent media, where they are so bent or refracted as to be concentrated upon the retina, where the im- pression is recognized as the form of the object per- ceived. Rays of light passing from space into the eye are refracted, according to Bonders, by the anterior sur- face of the cornea, the anterior surface of the lens, and the anterior surface of the vitreous. The trans^Darent media through which the rays must pass to the retina, and in which the refraction is accomplished, form the dioptric system. The ideally normal eye is so constructed that rays from an infinite distance, that is to say, parallel rays, in traversing the dioptric system, are brought to a focus at the retina without an effort of accommoda- 150 FUNCTIONAL NERVOUS AFFECTIONS. tion. This normal condition of tlie eye is called em- metropia. The diagram (Fig. 3) shows the an^angement of the different structures of the eye and the relations of the elem en ts forming the dioptric sys- tem. The tough membrane, the sclera (S.), main- tains the general form of the globe, extending back- ward to inclose the optic nerve (O. N.), and forward as far as the cornea (C). Next within this sclerotic membrane lies the vascular membrane, the choroid (Ch.), having an expanse about equal to that of the sclera. The cornea is transparent, permitting rays of light to pass into the eye, where they make their way through the aqueous humor (A. H.) and pass through the opening in the iris (I.), which is the pupil. The rays then traverse the crystalline lens (C. L.) and the vitreous humor (V. H,), at length falling upon the retina (R.), the delicate nervous mem- brane which extends from the optic nerve and lies be- tween the choroid and the vitreous humor. If the rays are brought to a focus on the retina, this focus lies at a point somewhat external to the point of en- FiG. 3. — Diagrammatic section of the eye. «, sclera ; c, cornea ; i, iris ; ch., choroid ; r, re- tina ; ah, aqueous humor ; cl, crystalline lens ; vh, vitreous humor ; cap, capsule ; on, optic nerve ; ml, macula lutea. SUPPLEMENT. 151 trance of the optic nerve, where the retina becomes even more thin and delicate than in its general ex- panse. This point, which is exactly in the visual axis, is called the macula lutea (M. L.). The point at which the optic nerve enters the eyeball is called the optic disc. The crystalline lens is held in position by an extremely delicate enveloping membrane called the capsule (Cap.), which is connected vdth the muscular ring, the ciliary muscle (C. M.). If an object which is clearly defined upon the screen of a camera be moved nearer to the instrument or carried farther from it, the image upon the screen will be no longer well defined, but indistinct. In this case the clear definition may be restored by changing the relation of the lenses to the screen, by moving them backward or forward, or the lenses may be re- placed by others having greater or less refracting power. If the eye were so constructed that its focal adjust- ment was always the same, objects only within a cer- tain range would be well seen, and all objects re- moved beyond or brought within shorter range would be indistinctly perceived. This condition is provided against by the faculty possessed by the eye of chang- ing, within certain limits, its refractive state. This is called the faculty of accommodation, and it must be brought into action whenever the eye regards objects nearer than the most distant point of clear vision ; and thus during waking hours it is almost constantly exer- cised. The theory of the mechanism of accommoda- tion of the eye was long one of the most interesting of 11 152 FUNCTIONAL NERVOUS AFFECTIONS. physiological inquiries, and many suppositions and speculations were from time to time accepted. The tirst to discover and to demonstrate the actual changes which occur in the exercise of this important function was Dr. Thomas Young. From the era of Kepler until the time of Dr. Young's contributions to the " Philosophical Transac- tions " in 1801, much had been written and but little had been known of the nature of this faculty pos- sessed by the normal eye of adapting itself to bring to a focus rays of light emanating from points at differ- ent distances. Young, by experiments, and by what, had they been properly understood, should have been regarded as conclusive arguments, showed that the change of focal adjustment of the eye in accommoda- tion depends upon alteration in the degree of con- vexity of the crystalline lens. A similar hypothesis had previously been held, but no demonstrations had been adduced. Little attention was paid to Young's theory un- til Helmholtz and Cramer, working independently, proved by mathematical and ocular demonstrations the truth of the theory. This important iDhysiological problem having been solved, it remained to others, and notably to the illustrious Professor Donders, to de- velop the theories of accommodation and refraction in respect to individual defects. The result of Professor Donders's labors in this direction were given to the world in his great work, " On the Anomalies of Accom- modation and Refraction of the Eye," published in 1864. SUPPLEMENT. I53 According to tlie present knowledge of the function of accommodation, the ciliary muscle, a small muscu- lar ring situated in the interior of the eye and sur- rounding the border of the crystalline lens, acting ui^on the lens in such a manner as to modify its curva- tures, and hence its refracting power, is the seat of the faculty of accommodation. According to the investigations of Cramer and Helmholtz, it is shown that in the act of accommo- dating the eye for near points the lens becomes con- vex, its anterior surface advancing toward the cornea, while the i^osterior surface remains nearly stationary, a change produced by the contraction of the ciliary muscle. When this contraction is discontinued, the lens resumes its original form, and the eye is adjusted for distance. The modification of the convexity of the lens, when accommodated for distance and near points, is well shown in the accompanying diagram : Fig. 4. In Fig. 4 parallel rays are shown by the solid lines which enter the eye, where they undergo refraction 154 FUNCTIONAL NERVOUS AFFECTIONS. and meet exactly at tlie macula lutea. The inter- rupted or dotted lines represent rays coming from a near point. These rays diverge as they ai)proach the eye. Hence, if they are to meet at the macula, they must be more strongly refracted than the parallel rays represented by the solid lines. To accomplish this the ciliary muscle contracts, thus becoming a ring of less diameter. (The dotted lines at the ciliary muscle show the change in its form). This contraction in the diam- eter of the ciliary ring relaxes the tension ui)on the capsule, when, by its innate elasticity, the lens as- sumes a more convex form, as is seen in its dotted out- line. This stronger convex lens now refracts more strongly than before, and thus the diverging rays are brought to a focus exactly at the point at which the distant or parallel rays were when the eye was at rest. As soon as the force of contracting the ciliary ring is removed, its diameter is increased, the tension upon the capsule is renewed, and the lens returns to its original state. In an ideally constituted eye, the distant point of clear vision {punctum remotum) is the horizon or in- finite distance. Parallel rays are brought to a focus without effort on the part of the ciliary muscle, and pencils of light from the retina pass out of the eye in parallel rays. Objects situated at about twenty feet from the eye send to it rays which are practically parallel, and hence in ophthalmology objects seen at twenty feet are regarded as at infinite distance. The distance between the remote point {punctum remotum) and the nearest point {punctum proxlmum) SUPPLEMENT. 155 of clear vision, representing the extent of accommo- dative power, is called the range of accommodation. Accommodation is a positive force acting only in pro- ducing clear vision as objects apiDroach within finite distance. It can not act to magnify very distant ob- jects by a process of negative accommodation. The crystalline lens, like every other tissue of the body, becomes less elastic with each year of life. Hence the power of accommodation diminishes and the near point advances toward the distant on account of the constantly increasing difficulty of changing the curvatures of the crystalline lens by the action of the ciliary muscle. At the age of twenty the near point is at about ten centimetres (eight and a half inches) from the eye, while at the age of forty it has reached to twice that distance, and at seventy-five it has been gradually transferred to the remote point. In other words, the faculty of accommodation is at that age practically lost. It is evident that in this gradually ]3rogressive re- moval of the near j)oint there must come a time when the normal eye can not clearly see objects within the ordinary distance of reading, and artificial help in the form of glasses becomes necessary. This, to the best eyes, occurs between the ages of forty-five and fifty, and the condition of accommodation demanding such aid is called presbyopia. Presbyopia is not necessarily a failure of visual power, nor is it, as is commonly sup- posed, an indication of perfect eyes that one is able to read without the aid of glasses after the age of fifty. 156 FUNCTIONAL NERVOUS AFFECTIONS. People who read without glasses after that age are near-sighted, or have some other defect of the eye. As the practical treatment of presbyopia is mate- rially modified by errors in the refractive condition of the eye, its further consideration will be resumed after these errors have been discussed. EEFEACTION OF THE EYE. All eyes are not constructed on the plan which has been shown above. Some eyes are longer and some shorter than in emmetropia, and some have irregular refracting sur- faces. These conditions, va- rying from em- metrojDia, are, according to D onders, known as conditions of ametropia. Fig. 5. — This represents the form of the emmetropic eye, in which parallel rays are brought to a focus at the back of the eye, without an effort at accom- modatioQ. If the eye is short, and j^arallel rays, could they pass beyond the back of the eye, would come to a fo- cus behind the retina, the con- dition is called hypermetro- pia or Tiype- ropia (Fig. 6). .Fig. 6. — The hyperopia or short eye. The solid lines represent the course which parallel rays would take were the back of the eye transparent. A convex lens, placed in front of such an eye, gives the rays the di- rections shown by the dotted lines, which meet at the retina. SUPPLEMENT. 157 Fig. 7. — The myopic eve. It is too long. Par- allel rays, shown by the solid lines, unite before reaching the retina, and must cross and fall upon it in diffusion. A concave lens causes the rays to enter the eye in a diverging man- ner, and they unite farther back, as shown by the dotted lines. If, on the contrary, the eye is long, and x)arallel rays come to a focus in front of the retina, the con- dition is kno\Yn as myopia (Fig. 7). An astigmatic eye is one in which there is a difference of refraction in dif- ferent meridians. Thus, in one meri- dian of an eye, em- metropia may ex- ist ; while in a me- ridian at right angles to this, myopia or hyperopia may be found. HYPEROPIA, OR FAR-SIGHT (h.). Hyperopia (Fig. 6) is one of the most common con- ditions which the ophthalmic surgeon is called upon to treat. It depends generally upon the form of the eye, which is too short, and dates from birth. It does not increase with age, except in a slight degree after the age of fifty, but, if neglected, may pass into the reverse condition, myopia."^ As, in this condition, the rays are not brought to a focus at the retina but behind it, when the eye is at rest, even distant objects are not seen clearly, and objects at near points are still less distinctly seen. But if the faculty of accommodation * Occasionally, also, hypermetropia may arise from too feeble re- fracting power, on account of flattening of the cornea, or of the sur- faces of the lens, or on account of absence of the lens (aphakia), or the refracting power of the aqueous humor or lens may be insufficient. 158 FUNCTIONx^ NERVOUS AFFECTIONS. is called into exercise, distant, and, with, greater effort, even nearer objects are seen clearly. The ability thus to bring the focus uiDon the retina will, however, de- pend upon the degree of hypermetroi)ia and the power of the ciliary muscle to effect the accommodation. As this faculty of accommodation is exercised without direct consciousness on the part of the individual, the fact that one has good vision, both for far and near points, does not show that hyperopia does not exist. It will be seen that even in viewing distant objects the accommodation must be used, and a greater de- mand for its exercise is made in seeing at near points. Hence hyperopic eyes are seldom at rest during waking hours, and a constant amount of contraction of the ciliary muscle is demanded. It is not surprising, therefore, that hyi)eroi)ic eyes, especially if required to perform much close work, as in reading or se^ving, suffer from a condition of fatigue known as accommo- dative asthenopia. The symptoms and results of hyperopia are due largely to this fatigue of accommodation, but the per- plexity arising from the absence of harmony between the functions of accommodation and of convergence has already been shown in the first part of this work (page 19). If the degree of hyperopia is slight and the power of accommodation active, little inconvenience may be experienced ; but if the vigor of the ciliary muscle is diminished, the eyes become painful, a dull, aching sensation is felt in and about the brows, the patient complains that letters and small objects be- come, after a short use of the eyes, indistinct. The SUPPLEMENT. I59 letters of a page, wliich at first appear clear, after a short time run together, and it becomes necessary to discontinue the work while the accommodation is re- lieved. Pressing the eyes with the hand, when this sense of fatigue is experienced, is a common and char- acteristic means of relief. If the act of accommodation is persisted in after these warnings, severe pain in and about the brow and at the back of the head, general discomfort, and nausea, may follow. As a result of frequent straining of the muscles of accommodation, hyperopic persons often have redness of the conjunc- tiva and of the borders of the lids. The more general and distant reactions have been shown in the first part of this work. In the higher degrees of hyperopia visual acuity is often diminished, so that even with correcting glasses the visual power is considerably less than the stand- ard. Bonders, to whom we owe the knowledge of the relations of these symptoms of fatigue to hyjperoiDia, divides the condition into latent and manifest hyper- opia. In latent hyperopia the patient unconsciously uses his accommodation, and thus conceals a part or the whole of the refractive error. This is especially the case with young persons, in whom the power of accom- modation is active, if the degree of hyperopia is only moderate ; but even a high degree of hyperopia may be associated with a vigor of accommodation sufficient to conceal it. As age advances, however, there comes a time when the lens being less elastic than in earlier 160 FUNCTIONAL NERVOUS AFFECTIONS. life, tlie accommodation no longer suffices to render even distant objects clear, and still less to enable the patient to read. The hyperopia is now manifest in part at least. A suitable glass may raise distant vision to the normal standard and the same glass may enable the subject to read. To ascertain the absolute amount of hyperopia, it is necessary, especially in all young persons, to render the latent hyperopia manifest, which can be accom- plished if we suspend the action of the ciliary muscle by atropia or other drugs XDroducing similar effects. MYOPIA, OR NEAR-SIGHT (m). Myoi:)ia is the condition opposite to hyperopia. The axis of the eye being usually too long instead of too short, as in hyjDeropia, parallel rays are brought to a focus in front of the retina, and, before reaching it, cross and fall upon it in circles of diffusion (Fig. 7). Hence, rays must be divergent as they enter the eye in order to meet at the retina. The far point of vision, then, for a myopic eye, instead of being at in- finite distance, is brought nearer, and a myopic eye is consequently a near-sighted eye. The distance of the remote point of distant vision will depend upon the amount of elongation of the eye. If this be slight, there will be a correspondingly slight degree of myo- pia, or near-sight. If, on the contrary, the elongation be great, there will exist an excessive degree of near- sight. Myopia, when dependent upon anatomical forma- te ^ SUPPLEMENT. 161 tion, is scarcely modified for tlie better by treatment, but unless suitable precautions are used there is a strong progressive tendency. Cases of slight myopia, if neglected, are liable to develop rapidly into high degrees of near-sight. It is important, therefore, that the first indication of near - sight in children should receive the most careful attention. The popu- lar prejudice which existed formerly that near-sight diminishes with age is erroneous, and should never be an excuse for relaxing the most vigorous attention to even the slightest degree of myopia. A slight change in the length of the eyeball after the age of fifty is, in this connection, a matter of technical rather than of practical interest. My own observations have con- vinced me that myox)ia is very frequently, if not in general, one of the results of anomalies of the ocular muscles, and that the condition most conducive to myopia is that in which the visual line of one eye tends in a higher direction than that of the other. In low degrees of myopia the defect may escape observation, as objects within certain distances are clearly seen, and the fact that objects beyond this point are not well seen is not regarded by the patient as in any way peculiar. Indeed, people with moder- ately high degrees of near- sight often become aware of their defect for the first time by accidentally put- ting on concave glasses, which reveal to them objects at a distance in a manner to them surprisingly clear. Usually, however, it will be observed that the myope holds a book or work nearer than the usual distance, and fails to recognize distant objects as well as other 162 FUNCTIONAL NERVOUS AFFECTIONS. people. In low or moderate degrees, glasses are not required for reading or writing, but in higher degrees work must be brought very near to the eyes in order to obtain distinct images, and in these cases concave glasses enable the myope to carry the book or other work to the ordinary distance. In near-sight, if of only moderate degree, the accommodation is com- monly used in reading and the book is brought near the eyes ; but, as age advances, the eye becomes pres- byopic in the same manner as in emmetropia. The near point recedes toward the distant i)oint, and thus, while the subject of myopia can see at no greater distance than before, there is a necessity for removing objects for near view toward the distant point. The slight change in the refractive condition which has been alluded to above, must not be considered here. The range of vision, then, is less extensive, but the near-sight remains. It was upon the facts that the book is held at greater distance, or that the glass for near-sight must be left off while reading, that the popular error that near-sight decreases with age was founded. Examining the history of near- sight in an individ- ual, it will, in the majority of instances, be found that until the age of from ten to fifteen years, vision for dis- tance was good, but that near-sight, then appearing, de- veloped rapidly. In a certain proportion of instances, however, myopia is developed at a very^arly period of life, and in a very small proportion of cases it may be congenital. The subjects of near-sight often suffer from redness SUPPLEMENT. 163 of the eyes and eyelids, from pain in the brows and general headaches, from intolerance of light, and from the presence of motes in the field of vision. Near-sighted eyes are commonly diseased eyes. The rapid elongation of the eyeball is often associated with disease of the choroid, and in some instances with separation of the retina from the choroid. A con- dition called posterior staphyloma, in which the scler- otic is distended backward, is often developed in my- opia. The principal changes, as described by Donders, are "atrophy of the choroidea on the outside of the optic nerve, when myopia is highly developed, com- bined with change of form of the nerve-surface, a straightened course of the vessels of the retina, incom- plete diffuse atrophy of the choroidea in other places, and morbid changes in the yellow spot." These changes can be readily recognized by the aid of the ophthalmo- scope. Fig. 8 shows the irreg- ular, white crescent which marks the atrophy of the choroid. Besides the elongation of the axis of the eye, myopia may be the manifestation of the increased index of refrac- tion of the dioptric media or of excessive curvature, as in conical cornea. A condition of involuntary and excessive contrac- tion of the ciliary muscles {spasm of the accommoda- 164 FUNCTIONAL NERVOUS AFFECTIONS. tion) sometimes occurs in young persons simulating myopia, and generally, after a time, resulting in tlie anatomical changes of myopia. If recogTiized in season the contraction of the ciliary muscles can be relaxed by the use of atropine continued for several days, and thus one suifering from apparent myopia and threat- ened with organic myopia may by this simple measure be saved from a great impending misfortune. Even this relief may, however, be only temporary, for if the cause of strain or irritation which in the first instance induced the spasm of the ciliary muscle is permitted to remain, the same spasm may return. Hence, as soon as the spasm is relaxed, every effort should be made to find and to remove the source of trouble, which is likely to be found in some unfavorable rela- tions of the motor muscles of the eyes or in some per- plexing state of the refraction. Myopia prevails mostly among the educated classes. The tension of accommodation demanded in looking during many hours of the day at near objects acts as an immediate cause. This cause becomes intensified in case the light is insufficient or is badly arranged. Hence the evils of badly- illuminated school-rooms have, very properly, engaged the attention of those who have studied the causes of myopia. Repeated examinations in schools and universities on a large scale have shown that myopia is progressive from the lower to the higher classes, a greater percentage of myopia existing in the higher classes than in the lower. This increase in the percentage of myopia is not to be wholly accounted for by such causes as de- SUPPLEMENT. 165 fective light or illy-constructed desks. The cause must be sought for in conditions more radical than these. The relations of the ocular muscles constitute, in my opinion, the most imi^ortant predisposing cause of myopia, and in this direction the most careful search should be made and the most Judicious precau- tion should be exercised. This, however, should not for a moment encourage any relaxation from the most minute regard for the hygiene of the school-room or of offices or other places in which the ejes are brought into prolonged use at close range. Defective light, imiDure air, and too greatly-prolonged exercise of the accommodation of the eyes, all consj)ire to act as im- mediate causes of myopia. Myopic children naturally find less pleasure in out- of-door amusements than other children, and are in- clined to employ much of their time in reading. This inclination should be checked, and the amount of close work performed by the child should be rather less than in excess of the amount of similar work allowed to an emmetropic child. ASTIGMATISM. Parallel rays of light traversing a convex si^herical lens (not regarding spherical aberration) unite beyond the lens in a luminous point. If the lens be bent in such manner that the curve in one direction is greater than in another, say at right angles to the first, the rays are not united in a point, but rays passing through the part of the lens most strongly curved unite first ; those traversing the part or meridian of 166 FUNCTIONAL NERVOUS AFFECTIONS. weaker curvature unite at a greater distance behind the lens. If the rays after passing through such a lens were received upon a screen, they would form not a point, but a line. In the emmetropic eye the dioptric system may be regarded j)ractically as a spherical lens, but in as- tigmatism the refraction is not uniform in all the re- fracting meridians. In what is called regular astigma- tism, difference of refraction exists in different meridi- ans, the greatest and least refractive power being in the meridians at right angles to each other. If a c. Fig. 9, be the meridian of greatest refraction, c d is that of the least. In irregular astigmatism there are different degrees of refraction in dif- ferent parts of the same meridians. It is often a result of ulcer of the cornea or of irregularities in the form of the lens. It is seldom much benefited by glasses. Regular astigmatism exists in different forms. If the meridian of greatest refracting power is emme- tropic, if its rays unite at the retina, and the meridian of least refracting power be hyperopic, its rays unit- ing behind the retina, it is called hyperopic astigma- tism. If the meridian of highest refracting power is myopic, its rays uniting in front of the retina, and the meridian of least refracting power be emmetropic, it is myopic astigmatism. If both the meridians of greatest and least re- SUPPLEMENT. 167 fractive power are liyperoj)ic, one more than the other, it is compound Jtyperopic astigmatism. If both meridians are myopic, one more than the other, it is compound myopic astigmatism. If one meridian is myopic and the other hyperopic, it is mixed astigmatism. Astigmatism, in most instances, depends upon de fective curvature of the cornea, which, instead ol being curved in all directions alike, is more strongly bent in some directions than in others. The general effects of astigmatism are similar tc those of the defects of refraction already described. In low degrees, little inconvenience may be experi- enced in the act of seeing, although it is evident that a perfect image is not obtained. In the higher grades much more trouble of sight results, as there must, oi' necessity, be much confusion in the focal adjustment for lines constituting an image, those which are more or less nearly at right angles to one another being sub- ject to different focal adjustments. In reading, the astigmatic, like the myopic person, brings the book near the eyes. There is generally, yd high degrees, defective vision even when correction by glasses is made, and hypersemia of the retina is not an uncommon complication. EXAMIJfATION AliD TREATMENT OF AMETEOPIA. — TEST- TYPES. Any two points of a retinal image, in order to be distinguished from each other, must have between! them a certain distance. This distance has been 168 FUNCTIONAL NERVOUS AFFECTIONS. shown by many experiments to con^espond to a visual angle of about one minute in tlie emmetrox3ic eye. Taking this princii)le as a basis, Snellen constructed his system of "test-types," which has been universally adopted for the demonstration of the acuteness of vision. The objects adopted are letters, graduated in size, both as to the parts and the whole, to correspond to different distances from one foot to two hundred feet. In order to test the acuteness of vision, letters are placed at a point sufficiently distant to exclude the act of accommodation. The point most generally selected is twenty feet, or about six metres, and an emmetropic eye, with normal acuteness of vision, should read the characters of No. XX (No. 6 of the new system) at twenty feet. If only No. XL can be read at twenty feet, the visual acuteness is ff, or only one half the normal. If only the type which should be read at one hundred feet is read at twenty feet, the visual acute- ness is ■^-^. Thus the numerator of the fraction de- notes the number of feet at which the eye is withdrawn from the type, while the denominator shows the line of smallest characters which can be read. In noting the result, we write, vision |^, if normal, or vision |^ or 1^, as the case may be. In general, the subject of the examination is not allowed to approach nearer than twenty feet ; but if vision is very defective, he is allowed to approach until the largest types are read. Thus vision may = ■^^, etc., the numerator showing the distance as before. The types used for near vision are, of necessity, SUPPLEMENT. 169 smaller. The smallest slioiild be read at eighteen inches. They are used chiefly for testing accommo- dation. The following is copied from Snellen's types: 0.5 D The Gallic tribes fell off, and sued for peace. ETen the Batavians became weary of the hopeless content, ■while fortune, after much capricious hovering, settled at last upon the Roman side. Had Civilis been saccess- ful, he would have been deified ; but bie misfortaneSf at last, made him odious iu spite of bi9 heroism. This type should be read with ease at the distance of one half metre, but in testing the accommodation the subject is required also to read it at twelve inches. The types of Iso. XX (6. D, new system) are shown below. U m If the person examined reads No. XX at twenty feet and No. 0.5 at about one and a half foot (one half metre), he is assumed to be emmetropic. He is not myopic, as he Avould not be able to read the characters at the greater distance. He may, however, be hyper- opic, and by the exercise of accommodation distin- guish the letters. If No. XX is not clearly seen with the unaided eye, but is clearly seen with a convex spherical glass, the focal length of the glass indicates the degree of manifest hyperopia. Thus, if the focal length of the glass is forty inches, the manifest hyper- opia is ^, or in the more modern system, 1. dioptry (H manifest = 1. D). If, on the contrary, a concave spherical glass of 170 FUNCTIONAL NERVOUS AFFECTIONS. forty inches negative focus (1. D) is required to render No. XX distinct, then myoiDia is ^^V? or 1. D (M = l.D). In determining astigmatism, radiating lines, the rays equaling in thickness the limbs of the letters of 'No. XX, are used. In testing the refraction with types at the distance of twenty feet the accommodation should be com- pletely relaxed. This is most effectually done by dropping into the eye, two or three hours before mak- ing the test, a small quantity of a solution of atropine of the strength of four grains to the ounce of water. This is rarely necessary after the age of forty, and not always even before that. According to the system which has long been in use, a lens is numbered according to its focal length, and its refractive power is represented by a fraction, of which the numerator is 1 and the denominator the focal length in inches. Thus, a glass of twelve inches focal length has refraction of yV- A new system has, within a few years, been intro- duced, in which the unit of refraction is no longer | inch, but a lens, the focal length of which is 1 metre. This is called a dioptry, and the refracting power is { metre. A lens of twice the refracting power would consequently be ^ = 2 dioptrics. A lens of one half the power C-^™) = '50 dioptry. If we wish to find the focal distance of a lens of this system we re- verse the fraction. Thus a lens otlD = \ =1 metre ; one of 2 D = ^ = ^ metre. As the degree of ametro- pia is expressed by the lens which corrects it, the sev- SUPPLEMENT. 171 eral degrees of refractive error are indicated in diop- tries. Thus, if by the old system H = ■^^, by the new H = 1. D ; and if M = ^ old, M = 2. D new ; M ^^ = 3. D. A given number of dioptrics may be reduced to the old numbers by dividing by 40 (40 inches being nearly 1 metre). Thus 1. D ^ 40 = ^V ; 2. D -^ 40 = ^ ; 3. D -T- 40 = 3^ ; and reversely the old numbers may be reduced to the new. Applying the principles of the test-types and lenses to the examinations of difficulties of refraction and accommodation, we shall be able, in a given case, to apply lenses which shall serve to reveal objects clearly at a distance, or assist vision for reading and -vvTiting, as the case may demand. In determining the defects in refraction the exam- iner should first carefully inspect the general appear- ance of the eye, observing its form and relation to its fellow, as well as any indication of clouds upon the surface of the cornea or of opacities behind the pupil. The acuteness of vision should be tested without the aid of glasses, and again with glasses. The condi- tion of the interior of the eye should be carefully de- termined by the aid of the ophthalmoscope, and evi- dences of imperfection in the refracting media or of disease of the deep structures carefully noted. In the diagnosis of ametropia the ophthalmoscope and various optometers may be used. In practice, however, a case of trial-glasses is absolutely necessary. With a view of furnishing a portable and compara- tively inexpensive case of trial-glasses, such as may 172 FUNCTIONAL NERVOUS AFFECTIONS. be fully equal to the requirements of the general prac- titioner, but which does not include glasses unneces- sary except after cataract operations or in rare cases, the author has devised a case which he believes fully meets the requirements. The object is attained by including in a single set of lenses all those numbers more commonly in use. All the numbers of spherical lenses contained in Na- chet's large case up to 10. D (old No. 4), are retained, with such other glasses as are best calculated to produce all the higher denominations with the least trouble. By combining not more than two lenses at one time, all the numbers of the best trial cases may be readily obtained. A similar arrangement holds in regard to cylindrical lenses. IN'umbers frequently re- quired correspond to those of the most complete trial cases, while all the others can be obtained with perfect ease by simple combinations. The lenses are constructed upon the metrical sys- tem ; hence, combinations can be made without any complex mathematical calculations. The case also contains a set of prismatic glasses, opaque and stenopaic disks, plain and colored glasses, and an adjustable trial-frame. With this trial case, all the examinations in regard to refractive conditions or muscular anomalies can be made as conveniently as with the most complete and expensive case. If the examiner, being provided with suitable trial- glasses, wishes to ascertain the refractive condition of the eye to be examined, he excludes the other eye from the act of vision by i)lacing in his trial-frame an opaque SUPPLEMENT. 173 disk, or by any suitable device. The person examined is now requested to read tlie letters of the trial-card, and the extent to which the letters are seen is noted. If the letters of No. XX are read at twenty feet, we conclude that myopia does not exist, and we are to de- termine the presence or absence of hyxDeropia or a mod- erate degree of astigmatism. The myopic vision is unable to adjust by accommodation for a distant point, but one in whom the faculty of accommodation is ac- tive may conceal a low degree of astigmatism or a high degree of hyperopia. If the patient sees as well with a convex glass of any denomination, as without, mani- fest hyiDeropia, equal to the strongest glass thus ac- cepted is proved. But let us suppose that the type of 'No. XXX is read, and that No. XX can not be clearly made out. Vision is then f f , and if no disease or ob- struction exists it may be hoped that vision can be raised to f-g^. First, a very weak convex spherical glass (•50 D) is placed before the eye ; if vision is somewhat improved, a stronger and stronger may be tried, until the best results are attained. But, before the eye be- comes fatigued, the effect of a weak convex cylindrical glass should be compared with that of the spherical. The cylindrical glass should be placed in various posi- tions before it is rejected. If the convex si)herical aids vision and the cylinder does not, to an equal extent, simple hyperopia is to be assumed. In case neither the convex spherical nor cylindrical lens aids vision, but rather renders the characters indistinct, concave spherical and then cylindrical glasses are to be tried in the same manner. In case neither assists the eye, we 174 FUNCTIONAL NERVOUS AFFECTIONS. are to assume that no refractive error exists, unless, with, the ophthalmoscope, we are able to discover the refractive anomaly. We have emmetropia with but |^ vision. If the eye subjected to examination is hyperopic, and is fully under the influence of atropine, the abso- lute hyperopia may be discovered ; otherwise, we can determine only the manifest refractive error. The strongest glass which is found to give addition- al sharpness of detail to the letters represents the de- gree of manifest or absolute hyi^eroi^ia, as the case may be. It is not to be forgotten that when atropine or some other mydriatic is not used, a certain amount of hyperopia may remain latent ; that the sum of the manifest and latent hyperopia equals the total. Hy- peropia which may be latent at one time may become manifest at another. Hence the glass which appears to correct the manifest refractive error at one time may be found at a later time to be too weak. If a convex glass of 1*00 D corrects the absolute hy- peropia, then H = 1 "00 D ; but if it is only the manifest hyperopia of an eye which may, under the circum- stances, exercise its accommodation, Hm = l-OOD. The question of the extent to which glasses should be used in hyperoi)ia is an important one. Theoretically, the accommodation should be re- lieved from all but the amount of exercise which would be required in emmetropria, but practically it is found more convenient, in many instances, to allow the eye to subject itself to a certain amount of accom- modative effort at a distance. SUPPLEMENT. I75 Children with moderate hyperopia need not, as a general rule, use glasses for distance. But if an in- sufficiency of some of the ocular muscles exists, there may be an advantage in their use even for distance. If the child suffers from nervous complications, such, for instance, as chorea or headaches, it may also be advisable to employ the glasses habitually. In other cases a glass of rather less strength than corrects the absolute hyperopia is to be used for near work. In high grades of hyperopia, or in case of loss of accom- modation from age or other cause, the hyperopia should be corrected for aU distances. After the age of forty-five or fifty, most hyperopic persons will require two pairs of glasses : one for cor- recting the hyperopia, to be used for the distance ; the other stronger, neutralizing both the hyperoi^ia and presbyopia. Let us suppose that, in the case already assumed, a convex glass does not improve but rather dulls vision at the distance of twenty feet, and that a concave glass serves to render the letters of the trial-card more dis- tinct. Myopia is to be assumed, and the weakest con- cave glass giving the most distinct vision at twenty feet, the accommodation being relaxed, represents the degree of myopia. In determining the degree of myo- pia, we begin by selecting a glass of low and gradually of higher power, until the lens affording the greatest improvement in vision is found. We may form an ap- proximate conclusion in respect to the degree of myo- pia by finding the greatest distance at which ordinary print can be read. We estimate the distance at which 176 FUNCTIONAL NERVOUS AFFECTIONS. the page becomes indistinct, wliicli indicates the far point of vision. If this is less than the distance at which the same page would be read by the emmetropic eye, myopia is presumed. If the distant point for reading the type 'No. '50 be one fourth of a metre (about ten inches), we have, ap- proximately, myopia 4*00 D, or ■^. "VVe may now try the effect of a negative glass of 4*00 D (of the old system No. 10), generally with the effect of enabling the letters to be carried to the distance of half a metre, and of materially improving vision at the distance of twenty feet. We now seek for the weakest glass that will en- able the patient to see well. It is not to be forgotten that the strongest convex glass with which the patient can see well at a distance, and the weakest concave glass with which vision is not less acute than with those of stronger power, represent respectively the manifest hyperopia and the grade of myopia. If, now, in the case above supposed, we can obtain a slight increase of vision, or even equal vision, by plac- ing in front of the 4*00 D lens a weak convex glass, say of -j- '50, our correcting glass is too strong, and must be reduced to the extent of the value of the sec- ond glass. On the contrary, if a weak concave glass assists, we must increase the strength of the original glass in a corresponding degree. In practice, the subject of myopia should always use the full correcting glasses for distant seeing, but this may be less convenient for near work. The ac- commodation is often enfeebled in myopia, and the effort at adjustment for near points, such as would be SUPPLEMENT. I77 required for the emmetropic eye, may become wea- risome. In this case glasses should be used of less strength than those demanded for distance, or if the myopia is of but very moderate degree, glasses may be left off in reading. Again, if the distance at which the eyes are to be used is such that the individual does not see well without glasses, and is fatigued by the use of those employed for distance, we may reduce the strength of the glass according to the distance required. Thus, if the distance is that for ordinary reading (about one half metre), we reduce the glass 2*00 D ; but if the glass is required for a somewhat greater distance, as for instance by a public speaker who wishes to refer to his notes, or by one who would read music at a piano, we estimate the distance at about thirty inches, or three fourths of a metre, and deduct from the strength of our glass 1*33 D, or, in practice, 1'50. We find the amount of such deductions by dividing 1 by the dis- tance in decimals of a metre. Thus, for one half metre, i^ = 2-00 and 1^=1-33. As the nearest approxi- mate number to this last in the trial-cases is 1"25 or 1-50, we may select, according to the case, the stronger or weaker number. The determinations of refraction are not always as easy as in cases of simple hyperopia or myoi^ia. In a very considerable proportion of cases of anomalous re- fraction astigmatism exists. This may render the diag- nosis of the precise refractive error extremely difficult, and much practice and skill may be required in arriv- ing at a proper result. The general rules for determin- ing astigmatism are not so complex that they may not 178 FUNCTIONAL NERVOUS AFFECTIONS. Fig. 10.- -Dr. Snellen's test-lines for astig- maliaui. be understood without much difficulty, but in practice the examiner will often find that he must rely largely upon his own tact and experience rather than upon fixed rules. The tests for astigmatism depend upon the fact that an astigmatic eye, in looking at lines drawn at different angles with the horizon, sees some lines more clearly than others. On this principle, the fan of Snellen and the radiating lines of Green are con- structed. A reduced copy of each is here represented. The thickness of the lines is made to correspond with the thickness of the limbs of the let- ters of the test-types for twenty feet. After satisfying ourselves that, in the case to be examined, there is an absence of disease of the inte- rior of the eye and of obstructions to the passage of light, tests for hyperopia and myopia are made. The examiner having ascertained whether either of these conditions exists, corrects any hyperopia or myopia which may be found with a convex or concave glass, as the case may be. If neither of these con- ditions is found, no spherical glass will be required. Fig. 11. — Dr. Green's test-lines. SUPPLEMENT. I79 If, then, there remains a defect of vision, the patient is required to state whether the radiating lines are all seen equally well. If one line or group of lines is seen with greater clearness than the others, this line indicates the meridian of the eye in which the fault is to be found. K the lines of Dr. Green are used, we inquire, first, respecting the contrast between the vertical and the horizontal group. As these bear the numbers of a clock-dial, we find, for instance, whether the group from XII to VI is more or less clearly seen than the group from III to IX, or, in other words, whether the vertical is more distinct than the horizontal, and many like questions, if need be, in or- der to understand the location of the contrasting groups. Having learned that one group of lines, for instance, that from III to IX, is most clearly seen, the examiner places a cylindrical lens before the eye with its axis at right angles with the line best seen, in this case vertically, or, as marked on the scale of the trial-frame, at 90°. A convex or a concave spherical glass may now be found which will render this horizon- tal line as clearly visible as the line at right angles to it was at first, and the value of this glass will represent the difference of refraction of the two meridians. Or, a convex cylinder may be first used, when, if it proves unsatisfactory, a concave cylinder of low power is tried. If, with a convex cylinder of low power, with its axis at a right angle to the line most clearly defined, the diagram appears in aU respects more plainly visi- ble and more uniform, we have hyperopic astigmatism. 180 FUNCTIONAL NERVOUS AFFECTIONS. If, on the contrary, a concave cylinder similarly placed is demanded to improve the clearness and uni- formity of the lines, we have myopic astigmatism. In either case the strength of the cylindrical glass which renders the lines most perfectly seen in all meridians represents the degree of astigmatism. The diagnosis of a low or moderate grade of myopic as- tigmatism in a young person should not be accepted if atropine is not used. The test-letters should now be brought into requi- sition, and if, with the glass selected, the best possi- ble vision is obtained, it is the glass to be ordered for constant distant use and for all purposes, if pres- byopia does not exist. Much may be gained in certain cases by varying the strength of the glass while exam- ining with the test-letters, and, in case that both a spherical and a cylindrical lens may be demanded, we may alternately weaken or strengthen one at the ex- pense of the other. In case of the demand for both spherical and cylin- drical lenses, we have compound astigmatism. In this case we first find the spherical glass which will render one line clear, then leaving this glass in place we test for the cylindrical, which will render the ray at right angles to it clear. In mixed astigmatism the correction is first made either by a spherical glass, as above directed, when a cylindrical glass of opposite refracting quality is used to correct the opposite meridian. If, for example, a convex spherical glass of I'OO D corrects the horizontal meridian, while a concave spherical of 1*00 D renders SUPPLEMENT. 181 the vertical line most distinct, we may, in this case, use a convex spherical of 1"00 D, combined with a concave cylindiical equal in strength to the spherical, together with the degree of myopic astigmatism, that is, of 2*00 D with its axis horizontally ; otherwise we may emj)loy a convex cylindrical glass of 1"00 I) with its axis verti- cal, combined with a concave cylindrical glass of 1"00 D with its axis horizontal. These two combinations will produce practically the same result, and will make all parts of the diagram equally distinct, and hence effect a correction of the astigmatism. It is evident that glasses for the correction of astig- matism must not only be ground to meet the indica- tions of the unequal errors, but that they must be accurately placed before the eye in order to correct the proper meridians. The frames which accompany the best boxes of trial-glasses are supplied with a scale on which is engraved the degrees of a half-circle, by which the examiner is enabled to determine and prescribe the position of the axis of each glass. Certain signs are, for convenience, employed by oculists in prescribing or recording the elements of compound glasses. Let it be required to prescribe a glass composed of the following elements : Spherical -f I'OO D combined with cylindrical -f 0-75 D, with its axis at 90°, we write : S + 1 -00 C cyl. + -75, 90°. If two cylinders, a convex and concave, are to be combined, convex 2-00 D at 90'', with concave 1-50 D at 1-80°, we write: cyl. + 2-00, 90° [cyl. - I'SO, 1'80°. The method of examination described above is a 182 FUNCTIONAL NERVOUS AFFECTIONS. conyenient one, but is only one of several which, may- be used, according to the inclination of the oculist. Astigmatic eyes are often poor eyes, and vision is, in some cases, only moderately improved by correc ting- glasses at first, although in a certain proportion of cases marked improvement may be observed after several months. UNEQUAL REFKACTION OF THE ETES (ANISOMETROPIA). It is not uncommon to find a difference in the re- fraction of the two eyes. One eye may be emmetropic and the other myopic, hyperopic, or astigmatic, or there may be different degrees of ametropia in the two eyes. If the difference is small, it is best to correct the error of each eye. If, however, there is great dispari- ty of the refractive conditions, much difficulty may be experienced by the patient in trying to correct both. In such cases there is usually found very marked anomalous tendencies of the ocular muscles which seriously complicates the situation. Before glasses perfectly adapted to each eye can be used with com- fort in such extreme cases, it is necessary to establish muscular equilibrium, after which there is a better prospect of harmonious action of the two eyes. TREATMENT OF PRESBYOPIA. It has already been shown that presbyopia consists of the gradual recession of the near point of clear vision toward the distant point. At the age of forty- five, owing not to the flattening of the eyeball, as has SUPPLEIklENT. 183 been popularly supposed, although a slight change in the length of the axis of the eye actually occurs, but to the loss of elasticity of the crystalline lens, the em- metropic eye finds some difficulty in reading fine type, especially in the evening. According to Bonders, the near point of clear vision in the emmetropic eye is, at the age of ten, two and two- thirds inches in ad- vance of the eye ; at twenty it is three and a half ; and at forty a little more than eight inches removed from the front of the eye. There is, then, no absolute point where the change to presbyopia commences, and the selection of a point which shall be regarded as presby- opia is entirely arbitrary, based upon the needs of the great majority of those who require glasses on account of advancing age. Bonders fixes the point of com- mencing presbyopia as that at which the near point has receded to more than twenty-two centimetres, or about nine inches in front of the eye. Adopting this as the commencement, we determine the degree of presbyopia in a very simple manner. If we bring small letters (No. 0*5) toward the eye until we find the nearest point of clear vision, we calculate the difference between this point and the point of com- mencing presbyopia ; thus : Presbyopia = -^ — l. ; n in the formula represents the near point ascertained. ltn = 12 inches, then the formula reads : P = i - iV = ^. Presbyopia then = -gig-, and a glass of thirty-six inches focal length is required to bring the near point to nine inches. 13 184 FUNCTIONAL NERVOUS AFFECTIONS. Substituting the metrical system, in wMcli a lens with the focal value of nine inches is represented by 4 '50 D, and one of twelve inches by 3*25 D, and our formula will be 4-50 -3-25 = 1-25. The following table indicates the lenses which, according to Bonders, are required for presbyopia of emmetropia at different ages : Age. D Inches. Ago. D iDches. 45 1-00 V.0 66 4-50 v« 50 2-00 %o TO 5-50 Vt 55 3-00 Vl3 75 600 VeH 60 4-00 Vio 80 7-00 'k^ It must not be supposed that every pair of emme- tropic eyes will find these glasses exactly suited to the necessities of close work. The distance at which work is to be done is to be considered in the selection of the glasses ; thus a public speaker who reads his notes while speaking will require glasses, other circum- stances being equal, weaker than one who works at a desk. Again, vision of emmetropic eyes, through the influence of muscular insufficiences or other causes, is not unfrequently less than the normal standard. Hence, glasses must be adapted especially to the indi- vidual. It is evident that if hyperopia, myopia, or astigma- tism exists, either condition must be taken into con- sideration. If hyperopia exists, the amount must be added to the degree of presbyopia shown in the table. If myopia is present, it is to be deducted ; and SUPPLEMENT. 185 in a case of astigmatism, the value of the correcting cylinder is to be added or subtracted. In determining the glasses required in an individ- ual case we employ test-types. Those in most general use for this purpose are Snellen's. These types are so graduated as to represent the greatest distance at which they should be read. Thus the smallest (see page 169), 0*5 D, should be read at one half metre (eighteen inches), the fourth at one metre (forty inch- es), and the sixth at l"oO metre. In testing presbyo]Dia, we first correct the amme- tropia by placing the proper glasses in the trial-case. The patient is then required to read the smallest types which can be read, and the nearest and farthest points are noted. In practice it is advisable not to force the eyes to read the smallest type at nine inches, but at a somewhat greater distance ; twelve inches may be ac- cepted. If the patient, in holding the card at twelve inches in front of the eyes, is able to read the types marked 1"25, and none smaller at this distance, we may place glasses of 1-25 D in the frames. It will now be found that No. '50 can be read at twelve inches. The type is then to be removed to the distance indi- cated by the number O'oO (eighteen inches), and if it can still be read at this distance, there is a reasonable amplitude of accommodation, and the glasses are not too strong. If the patient is quite myopic, the fully-correcting concave glasses may be left out of the trial-frames, and the weaker glass, which will permit the small types to be read at the specified distance, may be chosen. 186 FUNCTIONAL NERVOUS AFFECTIONS. In concluding this sketcli of the subject of refrac- tion and accommodation, it will not be out of place to call attention to some general points of interest which are incidentally related to the subject. Ametropic eyes — eyes varying from the ideal standard — are very common. It is an ordinary oc- currence for the oculist to find persons who believe that they are blessed with the best of vision, and who boast of its excellence, to have really quite de- fective eyes, and perha^DS very indifferent vision. To assume that one has excellent eyes because the name of a distant steamboat can be read by the possessor when others do not read it, or because the letters of a sign-board are seen when one's neighbor does not read them, is to presume that all the other persons who may be looking at these objects have perfect eyes, and that their attention has been equally directed to the object. Such tests prove nothing, and should not lead one to assume a perfection which may not exist. A very popular error is the supposition that one must have "strong" eyes because their possessor is able to see small objects better than others, and such a person is likely to boast of the ability of one or both parents to read without glasses until at an advanced age. It has been shown already that, when people who have passed the age of fifty are able to read without glasses, it is an indication, not of perfect eyes, but of myopia ; and when peoj^le see minute objects better than usual, we also conclude that they are near- sighted. Many people who have refractive or muscular disa- SUPPLEMENT. 187 bilities suffer from a certain degree of intolerance of light. To avoid tlie inconvenience arising from ordi- nary dayliglit, it is a not uncommon practice to em- ploy tinted glasses. It is even the practice of some oculists to prescribe such. The practice is not one to be commended. If the ej'es do not tolerate the light, the reason for the intolerence should be learned and removed. Proper attention to the refractive or muscu- lar states will, in the great majority of instances, afford complete relief. In case of disease of the eye, or in facing extreme light, colored protectors may be of temporary advan- tage. The material of which lenses should be made, and the manner in which they should be adapted to the face, are subjects worthy of consideration. Many people suppose that "pebbles" or lenses made of rock-crystal are much better than those made of glass. This is a popular error. The crystal has only the advantage of greater hardness, while it has the disadvantage of greater expense, and is very often less perfect optically than the glass lens. Glasses should be so adjusted to the face as to bring them in proper relation to the eyes. Formerly nearly all eye-glasses were so made as to hang downward upon the face, greatly interfering with the symmetry of the facial lines, and forcing the eyes to look through the borders of the glasses. Recently much improvement has been made in this respect. Such glasses should be made to permit the light to pass directly through the optical center of the 188 FUNCTIONAL NERVOUS AFFECTIONS. glass to tlie pupil. The borders should correspond with the lines of the brows. The glasses should be large, and the frames should not be conspicuous. Under these circumstances the natural expression of the face is not interfered with, and the glasses are much less conspicuous than when the facial lines are broken up. There is a general prejudice against the early em- ployment of glasses for presbyopia. It is thought that the eye should be forced to i^erform its function as long as possible without artificial assistance. This, if the condition were one of temporary failure of muscular tone, might be logical. In the actual state of the eyes such a prejudice is unwise. The eye in presbyopia is required to exert an amount of force which is entirely inconsistent with the well-being of the eye itself or of its possessor. If one persists in forcing the eyes to do close work without glasses after presbyopia has com- menced, the muscular iDower fails, and presbyopia in- creases more rapidly than if pro^Der relief is given at the right time. affeotio:n^s of the ocular muscles iisr which bi- nocular VISION MAY BE MAINTAINED. In the study of the relations of ocular conditions to disturbances of the nervous system, the affections of the ocular muscles occupy a position of paramount im- portance. The complicated system of muscles which co-oper- ate in adjusting the two eyes in such a manner as to obtain binocular vision under a multitude of circum- SUPPLEMENT. 189 stances, affords a subject of researcli attended oj diffi- culties but ricli in interest. In tlie act of binocular vision — that is, of vision in whicli tlie object seen by tlie two eyes makes but a single mental impression — the principal optic axes are in such exact relation to each other that a straight line drawn from the object through the pupil falls upon the yellow spot of the retina, the central point of vision of each eye, and at the same time each eye must be accurately adjusted in respect to its focus for the distance from it to the object seen. With every new adjustment of the eyes their rela- tions must be so precisely maintained as to permit the line from the point seen to fall upon this minute por- tion of the retina of each eye. Such ever-changing and extremely nice associated actions are demanded in no other part of the organism. The movements of the extremities, no matter how pre- cise or how delicate, make no such constant demand for minute precision ; and from no class of muscles, other than those that direct the eyes and regulate the accommodation, is the maintenance of i)erfect exacti- tude of service so constantly required. That this exacting service should, when difficulties in its performance are encountered, make excessive demands upon the stock of nervous energy of the in- dividual, or result in perplexities or irritations, is not surprising. Affections of the ocular muscles may be divided into those which result from physiological peculiarities and those which result from pathological conditions. 190 FUNCTIONAL NERVOUS AFFECTIONS. In tlie first of these groups, the muscles, while mani- festing no indications of disease, do not act in such harmony as to permit the most ready and easy com- binations of action. This group is divided into two classes : 1. Those which permit of habitual binocular vision. 2. Those in which a blending of the images of the two eyes is so difficult as to be, in most instances, impossible. The conditions of this class are known under the general term strabismus. The first of these classes has for a long time been known under the name of insufficiencies of the ocular muscles. For reasons which have been fully discussed else- where,* this term is regarded as indequate and often misleading. It has been shown that for some of these conditions no distinctive terms exist, and that to others the term insufficiency is improperly applied. Terms of more exact meaning are therefore required. Accordingly, the system of terms relating to the conditions, which was suggested in the works referred to, will be employed here. In this class of muscular faults, binocular vision is maintained by the expenditure of a greater amount of force than is required when the ocular muscles are in a state of perfect equilibrium. The visual lines are habitually held in such relations as to extend from the point of fixation to the yellow spot of the retina, but * " Archives d'Ophthalmologie," Paris, November, 1886 ; " New York Medical Journal," December 4, 1886 ; " Archives of Ophthalmology," New York, June, 1886. SUPPLEMENT. 191 only by persistent and special effort. The tendency is for the visual lines to part, for one of them to continue to unite the fixed point and the macula or yellow spot and for the other to fall upon some other part of the retina. Such tendencies are grou^Ded under the generic name Heteeephokia (eVe/jo?. different; (f)6po<;, a tending). This term includes the conditions which have been known as insufficiencies of the ocular muscles. Some of the most distinguished contributors to the science of affections of the eyes have given considera- ble attention to this subject, yet it has received vastly less consideration than its importance has demanded. To Graefe we are greatly indebted for important re- searches in this department ; and Horner, Nagel, Lan- dolt, and many others, have made valuable additions to the subject. The writings of Graefe were those of a pioneer and were not exhaustive. Others, however, have been content in great measure to accept the re- sults of Graefe's genius as in the main conclusive. The discussion of "insufficiencies" has been mainly, it may be said almost exclusively, confined to a single anomaly, and that not the one of greatest importance. When the eyes are directed to a distant object situ- ated directly in front of the observer and at a distance of from fifteen to twenty feet, the visual lines are prac- tically parallel, and in this position there should be the minimum of nervous energy directed to the muscles of the eyes. If this is the case, the ocular muscles are said to be in a state of equilibrium and in all other ad- justments the changes of relations required are made 192 FUNCTIONAL NERVOUS AFFECTIONS. with the least expenditure of effort consistent with the action. This condition, in which all adjustments are made by muscles in a state of physiological equilibrium, is called Orthophoria {6p6o<;, right; (f)6po<;, a tending). In the absence of orthophoria there may not be any actual turning of one visual line away from the other, but there is a tendency on the part of one or more of the eye-muscles to disturb the balance. Should the nervous control be so removed as to permit of the con- summation of this tendency, actual deviations would occur. Such disturbances of equilibrium are known, as above stated, as Heteroplioria. The deviating tendencies of heterophoria may exist in as many directions as there are forces to induce ir- regular tensions. The following system of terms is applied to the various tendencies of the visual lines : I. Generic Terms. — OrthopTioria : A tending of the visual lines in parallelism. Heteroplioria : A tending of these lines in some other way. II. Specifio Terms. — Heterophoria may be divided into — 1. EsopJioria : A tending of the visual lines inward. 2. ExopTioria: A tending of the lines outward. 3. HyperpTioria (right or left): A tending of the right or left visual line in a direction above its fellow. This term does not imply that the line to which it is referred is too high, but that it is higher than the other, without indicating which may be at fault. SUPPLEMENT. I93 III. Compound Terms. — Tendencies in oblique di- rections may be expressed as TiyperesopJioria^ a tend- ing upward and inward ; or Tiyperexophoria^ a tending upward and outward. The designation "right" or "left" must be applied to these terms. In recording the respective elements of such com- pound expressions we employ the sign 1 For ex- ample, if it is desired to indicate that the right visual line tends above its fellow 3°, and that there is a tend- ing inward of 4°, the facts are noted thus: Right hyperesopTioria, 3° l_ 4°. It will be seen that deviating tendencies in every possible direction can be minutely and accurately de- scribed by such a system. In seeking to discover these faulty tendencies the following method will be found convenient, and in the majority of instances satisfactory : The subject of examination is to be seated with the head in what is known as the "primary position," in which the head is held erect and the face is turned exactly toward the object to be seen, so that a line passing from the object to the face would meet a line drawn between the eyes at its center and at right- angles to it. The object to be looked at should be luminous against a dark background, a lighted candle being the best. It should be nearly upon a level with the eyes, and at a distance of twenty feet from them. If ame- tropia exists, it is to be corrected by appropriate glasses. Under these circumstances there should be the 194 FUNCTIONAL NERVOUS AFFECTIONS. minimum of muscular innervation; that is, ortho- phoria should exist. Orthophoria, or heterophoria, may now be deter- mined by means of prisms in the following manner : First of all, a prism of sufficiently high grade to in- duce diplopia is placed with its base toward the nose before one of the eyes. The two images of the object then seen are homonymous — that is, the right image is seen with the right eye, and the left with the left eye. If the two images are seen in exactly the same hori- zontal plane, no deviating tendency in this direction is manifest. If one of the images rises higher than the other, there is absence of equilibrium in this respect, and the condition is the one called JiyperpTioria. If in the test the left image of the object is seen higher than the other, it indicates that the visual line of that eye tends below that of its fellow, and that the visual line of the right eye has, in fact, a tendency to rise above the left visual line. This is right hyperphoria, and the state in which the right image is seen above the plane of the other is known as left hyperphoria. If, as in the first instance, the left image is higher than the other, we determine the degree of right hyperphoria by finding the grade of prism which, placed with its base down before the right eye, or with its base up before the left, will bring the two images exactly to the same horizontal plane, and the result is recorded accordingly. Thus, if a prism of 2° base down before the right eye corrects the deviation from the horizontal plane, we write Right hyperphoria, 2°. SUPPLEMENT. 195 It lias been said that in determining the relations of the ocular muscles, glasses suitable for the correction of existing ametropia should be supplied. In testing for hyperphoria this precaution is not essential, and may, in general, be neglected, especially if the correct- ing-glasses should be strong. A very slight variation from exact adjustment of the optical centers of the glasses to the centers of the pupils might induce a de- gree of apparent hyperphoria, which, if real, would be of considerable consequence. This test for hyperphoria should invariably pre- cede all other muscular tests. Next, diplopia is induced by placing a prism, with its base exactly up or down, before one of the eyes. In general, a prism of 7° is sufficient for this. If, after a moment, the images are seen exactly in the ver- tical line, no deviating tendency is shown. If, on the other hand, the upper image passes to the right or left of the other, heterophoria in this direction is shown. The two deviating conditions which may now be discovered are : Esophoria (eW, within) : A tending of the visual lines inward. ExojpTioria (e|, out) : A tending of the visual lines outward. If the deviations of the images are in the directions of the eyes to which they belong, the image seen by the right eye appearing most at the right and the image seen by the left eye at the left, the tendency is homonymous, and esophoria exists. If the image 196 FUNCTIONAL NERVOUS AFFECTIONS. seen by tlie rigM eye appears more to the left tlian its fellow, exophoria is shown. If, in making this determination, a prism of 7° is placed with its base down before the right eye and di- plopia is caused, the upper image will be the one seen by the right eye, the lower that seen by the left eye. If, now, the upper image appears more at the right than the lower, it indicates esophoria; but if the image should be seen more at the left than the lower, exophoria would be shown. In the same manner as in ascertaining the degree of hyperxohoria, Ave determine the degree of exophoria or esophoria. The prism which brings and holds the images in the vertical line measures the defect. Should both hyperphoria and esophoria or exo- phoria be found, the condition may be described by the compound tei-m hyperesophoria or hyperexophoria. The degree of each element of heterophoria is indi- cated thus : R. (or L.) Hyperesophoria, n° l_ n°. If, in a given case, it should be found that the right visual line tends above its fellow 3°, and that the lines tend inward 4°, the facts are noted thus : R. hyperesophoria, 3° l_ 4°. The absence of indications of heterophoria does not, of necessity, prove orthophoria. Heterophoria, like hyperopia, may be latent, and considerable time and much patience may be required to ascertain the true state of the muscles. The conditions which are to be found by the methods described are manifest, not absolute. SUPPLEMENT. I97 Hence, hyperphoria 1° by the tests described may, at length, prove to be hyperphoria 3° or 4°. The ten- sion at which the eyes are habitually held may con- tinue in part or entirely to conceal the absolute tend- encies. This important fact that heterophoria may be mani- fest only in part should not in any case be lost sight of. Many examinations may be required to determine, even approximately, the absolute heterophoria. In a certain proportion of cases, latent heterophoria may become manifest by the use of nominally correcting prisms in the same manner as latent hyperopia some- times becomes manifest after the use of weak convex glasses. Great caution is to be exercised in determin- ing the latent heterophoria, that an apparent anomaly is not actually induced by the use of correcting- prisms. It is possible, should one who has perfect equi- librium of the eye-muscles use prisms with the bases out for a few days, to find the conditions of esophoria in tests made immediately after removing the glasses. To assume that such a case is one of actual esophoria would evidently be a mistake. But should one who manifests 2° esophoria use a prism of 1° for a day or two, and then reveal esophoria of 3°, it would be quite safe to increase the prism to 2° ; and should the ex- cess of 1° over the correction continue several days, it would be safe to conclude that there is at least 3° eso- phoria. Having determined the deviating tendencies by the methods described above, similar tests may be made at 198 FUNCTIONAL NEEVOUS AFFECTIONS. reading distance. In these tests the method of Graefe is most conveniently employed. On a card, a fine, straight line is drawn through a dot (Fig. 12). Diplo- pia is produced as before, but prisms of con- siderably stronger grade may be required, when the observations are made in the same manner as when the test-object is situated at a distance. This test was used by Graefe for determining " insufficiency of the interni," and is the test described in text-books. The conditions found by it may be recorded as exophoria (or eso- phoria) in accoinmodation. Exophoria in ac- FiG 12. commodation corresponds to the condition de- scribed by Graefe and others as insufficiency of the interni. All these determinations having been made with sufficient care, the examiner proceeds to ascertain the relative power of the different pairs of muscles by find- ing the strongest prism with which images can be unit- ed in different directions. To determine the strength of the abductors, the prism should be held with its base inward. The standard of abduction adopted by the author is 8°. A prism of that grade should be overcome, and images of an object at twenty feet distance should blend. If the abducting power is less than this by two or three degrees, it is strongly suggestive of esophoria, even should esophoria not have been shown by the previous tests. It is to be remembered that heterophoria may be partly or wholly latent, and the fact that no esophoria SUPPLEMENT. I99 is manifest is to be considered in its relation to the power of abduction. Deficiency of abduction resulting from hyperpho- ria will be noticed below. The power of overcoming prisms with the base up or down may be tried before or after the trial for ab- duction. Commencing with a very weak prism, we try stronger, until the strongest that can be overcome in one direction is found ; then the strongest in the opposite direction. A prism with its base down before one eye is equivalent in its action to a prism with its base up before the other. The amount of power shown in overcoming a prism with its base down before the right eye is the degree of right sursumduc- tion. If the prism is placed before the left eye in the same direction, or if it is turned with its base up be- fore the right eye, it indicates the degree of left sur- sumduction. We can not make accurate determina- tions of both right and left sursumduction, if the test for one follows without interval after the other. It is, therefore, well to test in one direction before the test for abduction and in the other after it. The average ability of overcoming prisms in this manner is about 3°. In high grades of myopia it may reach 8° or 10° in each direction. Finally, the amount of adduction is to be deter- mined. Prisms are to be placed before the eyes with the base out and the strength gradually increased until the images can no longer be blended. The high- est grade of prisms overcome marks the adducting power. 14 200 FUNCTIONAL NERVOUS AFFECTIONS. The standard of adduction should be about 50°, but many, who after trials repeated daily for two or three times will accomplish an adduction to this extent, will not accomplish half the amount at the first trial. All the tests for sursumduction, abduction, and ad- duction should be made at the distance of twenty feet. HYPEKPHORIA. Hyperphoria is that condition in which, with the ability to maintain binocular vision, there is a tending of one visual line in a direction above that of the other. Strabismus, in which there is an actual turning of the axis of one eye above the other differs from hyper- phoria in the absence of ability to maintain single vision. Strabismics snrsiimvergens, and deorsum- Tergens were described and operative measures for their correction were long since pointed out. Special attention was first called to the condition of hyper- phoria as an important and frequent anomaly of the ocular muscles by the author of this work. Among the anomalous tendencies resulting from faults of equilibrium of the eye-muscles, hyperphoria is of pre-eminent importance. A slight deviating tendency in this direction is often of greater account than one of a considerable degree in others. The ability of the eyes to adjust the visual lines for the correction of a difference in their direction in the vertical meridian is much less than that for correcting a similar difference in the horizontal line. It has been SUPPLEMENT. 201 already shown that the power to overcome a prism placed with its base up or down before an eye is usually limited to about 3°, while in abduction a prism of 8° and in adduction prisms of 50° may be overcome when the normal standard of power in these directions exists. It is evident, therefore, that a deviating tend- ency of 1° or 2° in the direction of hyperphoria creates an excessive demand for correction upon muscles illy calculated to perform the duty. A still more imi)ortant element in the results of hyperphoria is its influence upon the action of the lateral muscles. In hyperphoria the eyes may be so influenced in their movements that, when directed to a distant object at the same height as the eyes, there is a strong tend- ency of the visual lines inward (esophoria) ; but if directed to a near object, especially if it is below^ the plane of the eyes, the visual lines swing outward, caus- ing a very marked exophoria in accommodation, or, as it is familiarly known, insufiiciency of the interni. Many of the most intractable cases of insufficiency of the interni are the result of this swinging movement of the eyes, and it is not rare to see asthenopic persons who are armed with powerful prisms for the correction of insufficiency of the interni, who have no other muscular error than a slight hyperphoria. Persons subject to hyperphoria are much more liable to be troubled with double images than those subject to simple exophoria or esophoria. Yertigo and confusion of vision are extremely com- mon symptoms of hyperphoria. Persons affected by 202 FUNCTIONAL NERVOUS AFFECTIONS. this anomaly, if weak or in ill liealtli, often experience a dread of walking in crowded streets unattended, fearing tliat tliey may fall or suffer from mental con- fusion in the crowd. The attitudes and facial expressions of hyper- phoria, while not universal, are quite characteristic. The head is, in a very considerable proportion of cases, carried habitually toward one shoulder. If the right eye tends higher than the left, the head is carried to the left shoulder; if the left eye tends above, the head is at the right. The efforts made by the eyelids to aid in forcing the eyes in position give certain peculiarities to the facial expression. One eje may appear partly closed, or both eyes are opened very widely with a kind of stare which has been described as "the hyperphoric stare." The eyes in hyperphoria have, in many instances, an unsteady gaze. One eye may appear to float away from the other and then back again. Vision is, in a considerable proi^ortion of cases, affected. It has been found that, in more than fifty per cent of cases, vision is less than two thirds the normal standard. Many cases of abnornal secretion of tears have their origin in this condition. They do not yield to the ordinary methods of treatment for such comj)laint, and are liable, by means of the excessive flow of tears, to result in distention of the lachrymal sac and in inflam- mation of the lining membrane of the nasal canal, leading to its contraction. In its reflex results hyperphoria is an extremely im- SUPPLEMENT. 203 portant element in neuroses. Especially in epilepsy and vertigo should it be looked for with great care. TREATMENT OF HTPERPHOEIA. The best treatment for hyperphoria is tenotomy of the muscle which forces the eye out of its proper di- rection. It is not always easy or even possible to de- termine to which muscle we are to attribute the vicious tendency. The superior rectus of one eye may be short, causing too great tension upward, or the inferior / rectus of the opposite eye may be at fault, tending to draw the eye downward, or one of the four oblique muscles may cause the loss of equilibrium. With all these elements of uncertainty, the highest skill of the surgeon may be demanded in forming a correct con- clusion. A complete knowledge of what is known of the physiological action of the various eye-muscles is essential in this examination. In the majority of cases, however, in which the hyperphoria does not ex- ceed three degrees, it is proper to relax either the supe- rior rectus of the eye of which the deviating tendency is upward or the inferior rectus of the other. In general, it will be found best to select the superior rectus. If more than three or four degrees of deviat- ing tendency is found, it is better to correct a part up- on the superior rectus of one eye and what remains of the defect upon the inferior rectus of the other eye some days later. The method of performing tenotomy in these cases of deviating tendencies less than strabismus has been * See page 135. 204 FUNCTIONAL NERVOUS AFFECTIONS. already described.* Since submitting this method to the Royal Academy, however, I have found it advisa- ble to modify the procedure somewhat, rendering the ox)eration more simx)le and the results more satisfac- tory. As now performed, the eyelids being retract- ed, a fold of the conjunctiva is seized by a fine but rather rigid pair of mouse-tooth forceps, parallel with the course of the muscle and exactly over its insertion. With a pair of small, narrow-bladed scissors, having blunt but very perfectly-cutting points, a transverse incision is then made through the membrane exactly corresponding to the line of insertion of the tendon. The conjunctival opening thus made should not exceed in extent one fourth of an inch. With the forceps now pressing the outer cut edge of the conjunctiva slightly backward toward the course of the tendon, the latter is seized behind, but very near its insertion. The distance may depend upon the freedom with which the intended section of the tendon is to be made. But in hyperj)horia, or in slight relaxations of the lateral muscles, a distance barely sufficient to allow a small part of the tendon to be raised from the sclera is all that should be allowed. Making some tension now with the forceps, the points of the scissors are directed against the central jiortion of the tendinous insertion and toward the sclera, when a small opening is made dividing the center of the tendinous expansion exactly on the sclera. The small opening is now to be en- larged by careful snij)s of the scissors toward each border, keeping more carefully on the sclera as the border of the tendon is aj)proached. As the section of SUPPLEMENT. 205 the tendon is carried toward the borders, the outer blade of the scissors passes beneath the conjunctiva. If the relaxation of the tendon is to be slight, the ex- treme outer fibers of the tendon are to be preserved untouched, but if a considerable effect is desired these fibers can be entirely severed, provided that the reflec- tion of the capsule of Tenon upon the tendon is not disturbed. By means of the capsule acting as an auxiliary attachment, the tendon is held in position but is allowed to fall back slightly while maintaining its relation to the eyeball. In this respect, and in pre- serving the outer tendinous fibers, this operation differs radically from the ordinary operation for strabismus, and from any operation which has been proposed for so-called "partial tenotomy" of the recti muscles. The judgment of the operator must determine the extent to which the division should be carried ; but, should it be found that too little has been accom- plished, the section can be extended. In doing this, the use of a very fine hook may be advisable. For this purpose a hook very much smaller and more deli- cate than the ordinary tenotomy-hook should be em- ployed. Its rounded point is carried under the re- maining border of the tendon vdth great care to pre- vent haemorrhage or unnecessary disturbance of the conniective tissues, the extension being made toward one and then toward the other border, as the demand for further relaxation may require. When the remain- ing band of fibers is made tense by the hook, it is slightly elevated from the sclera, when the fine-pointed scissors are introduced beneath the conjunctiva, and 206 FUNCTIONAL NERVOUS AFFECTIONS. the necessary extension of the wound is made with an extreme caution not to divide the capsular attachment. The conjunctival suture should in no case be employed. All bandaging of the eye or covers of any description are not only needless but mischievous. Bandages are promoters of heat, filth, and septicism. ESOPHORIA. Eso]3horia, or "insufficiency of the externi," is an exceedingly common and a very troublesome anomaly of the ocular muscles. In esophoria the relative ten- sion of the eye-muscles is such that, if the force of the will were to be removed, the visual lines would ap- proach each other and cross at a point less distant than that for which the eyes are accommodated. In stra- bismus convergens this tendency is carried to the ex- tent that one visual line constantly deviates from the direction of the other. In esophoria there is habitually an ability to bring the lines simultaneously to the same point. The effort required to continue this ad- justment may be, and in the great majority of in- stances is, made without the direct consciousness of the individual, and there is not of necessity any ap- pearance of deviation, although it is not uncommon to observe an appearance of insufficient distance between the eyes — giving, in this respect, a narrow facial ex- pression disproportionate to the general features. Graefe, in his extensive writings upon the ocular muscles, devoted only a passing notice to this condi- tion, his treatise on muscular asthenopia containing but a single paragrajDh relating to it. In this, how- SUPPLEMENT. 207 ever, lie was more liberal tlian most succeeding writers, and even the latest text-books on ophthalmology make no reference to the condition. The first notices of cases of treatment of " insufiiciency of the externi," in which no strabismus existed, and in which important results were obtained, were reported by myself in va- rious papers from 1876 forward. In the memoir to which this discussion is supplemental, more especial consideration was devoted to this condition than had been given to it in all previous writings, and the many instances of remarkable relief obtained from the cor- rection of this anomaly related therein precede any considerable discussion of the subject, and, indeed, constitute the principal contribution to it up to the present time. "Insufficiency of the interni" is the condition to which muscular asthenopia has been generally attrib- uted. We have already seen that hyperphoria is an element of the first importance in muscular asthenopia, and a careful perusal of the foregoing memoir will con- vince the reader that esophoria is also of equal signifi- cance with, if not of greater importance than, "insuf- ficiency of the interni." It is certainly of more fre- quent occurrence, and is, in a greater proportion of cases, attended with distant refiex disturbances. Among the symptoms very commonly observed as resulting from esophoria, are pain in the back of the head and in the back of the neck. Such pains often succeed an hour's visit to a gallery of pictures, attend- ance at a public gathering, where one confines the gaze for a considerable time upon a speaker ; and travel in a 208 FUNCTIONAL NERVOUS AFFECTIONS. rail-car, when tlie individual, the subject of esophoria, looks out upon the rapidly-changing objects of the landscape, is often the precursor of such occiipital headaches. Nervous exhaustion, palpitation of the heart, pain between the shoulder-blades and at the lower ^avt of the back, dyspepsia, and habitual constipation are among the very common reflex nervous phenomena re- sulting from esophoria. To ascertain the existence of esophoria and its de- gree, the test for hyperphoria having been already made, we first place a prism of about 7° with its base down before one of the eyes and cause the person exam- ined to look at an object twenty feet distant. Double vision results with the image before which the glass is jDlaced above its fellow. If, now, the higher image deviates in the direction of the eye before which the glass is placed, if the deviation is homonymous, there is esojDhoria, measured by the degree of prism, placed with its base out before either eye, which brings and holds the two images exactly in the same vertical line. In making this examination hyperopia or hyperoj)ic astigmatism, if of higher grade than '50 D, should be corrected by appropriate glasses. Moderate degrees of myopia or myopic astigmatism have little influence wpon the test. After determining the degree of eso- phoria by the vertical prism, the amount of abducting power is to be ascertained. Prisms with the base in are employed, requiring the person examined to make the strongest effort to blend the double images. The strongest prism which can be overcome marks the SUPPLEMENT. 209 power of abduction. This power should be equal to overcoming a prism of 8° with the base in. Let us suppose that esoj)horia of a certain degree has been found, and that there is aiDproximately a corresponding restriction of the abducting force. The diagnosis of esophoria of the given amount is clear. But if, by the vertical prism, no deviation is shown, and there is still a restricted abduction, there is proba- bly latent esophoria equal, at least, to the difference between a prism of 8° and that with which images can be blended. But let it be supposed that a very considerable de- gree of esophoria is found with a power of abduction exceeding the standard given above. One of two con- ditions must be presumed : There may exist an actual deviating tendency inward, and by constant efforts at its correction the power of the external recti may have been so greatly developed as to enable the individual to accomplish more than the usual abduction ; or, more probably, there exists hyperiDlioria. In this later case the esophoria may be aiDparent, the result of a swinging movement given to the eyes in the test, and the actual balance may be neither inward nor outward. The utmost caution and great patience are required in the management of this class of cases. A condition exactly opposite the one just supposed will be consid- ered in the discussion of exophoria. Again, should esophoria be found when testing for the distant point, and exophoria be shown in accommodation, we are to suspect hyperphoria, and the case should be carefully observed until this question is satisfactorily deter- 210 FUNCTIONAL NERVOUS AFFECTIONS. mined. After having made tlie examination at the distance of twenty feet, examination with the vertical prism is made at a distance of about eighteen inches. If esophoria is found, it is esophoria in accommoda- tion. TREATMENT OF ESOPHORIA. Esophoria may, under certain circumstances, be treated by prismatic glasses ; if refractive errors exist, the prismatic element may be combined with the spher- ical, or cylindrical glasses. This is the method of a crutch, and is inconvenient and by no means uniformly successful. Indeed, suc- cessful relief to esophoria, by means of prisms, would appear to be rather exceptional. It is a proper meth- od of treatment only when better methods can not be adopted. There are several reasons in the nature of such a correction why it should be unsatisfactory, which need not be discussed here. The radical and best method is tenotomy of one or both of the interni, performed by the method already described at page 203. Before resorting to an opera- tion it is always advisable that the power of adduction should be fully developed in the manner that will be shown in the section on exophoria. An adducting power of 50° should be shown prior to the opera- tion. EXOPHORIA. This is the condition which has been described in text-books as "insufficiency of the interni." The con- dition, however, differs in the respect that, whereas "insufficiency of the interni" has, by Graefe and in I SUPPLEMENT. 211 the text-books generally, been determined by the dot- and-line test at a near point, exophoria is the condition found at a distance when no accommodation is em- ployed. The condition described in text-books is here known as exophoria in accommodation. The condi- tions found by the tests known as the "cover- tests," and by holding an object near the eyes to observe the deviation of one or other, are perhaps better included in the limits of the subject of strabismus. Exophoria is discovered by means similar to those described for esophoria. If, with the vertical prism, the images cross, if the image seen by the right eye is at the left, and that seen by the left is at the right of the other, exophoria exists in the degree measured by the prism with its base inward, required to bring the two images to a vertical line. Exophoria in accommodation is tested in the same manner, but at the near point. If, with a certain de- gree of exophoria, abduction exceeds 8°, we have an undoubted condition of deviating tendency outward. If, on the other hand, exophoria is attended with re- striction of abductive force, we are to presume that hyperphoria exists, and that, as in the case of esopho- ria, under the reverse conditions, the apparent exo- phoria is the result of the swing resulting from the hyperphoria. Exophoria in accommodation is often associated with esophoria, and should never under such circum- stances be mistaken for an actual tendency of the eyes to deviate outward. The symptoms of exophoria are, perhaps, more fre- 212 FUNCTIONAL NERVOUS AFFECTIONS. quently than esoplioria, local. As a result of tliis anomaly, the condition of muscular asthenopia is com- mon, and is indeed the only condition usually associated with this anomaly in the literature of ophthalmology. In muscular asthenopia there is a sense of painful fatigue of the eyes after close work or reading ; an in- clination for the letters or words of the page to run together, or for one word to find itself superposed upon another. A feeling of tension and dull pain over the brows and in the back of the head is experienced, the latter, perhaps, more especially after a few hours have elapsed since the use of the eyes. The more distant manifestations of exophoria are the neurasthenic symptoms, which have already been mentioned as resulting from other forms of hetero- X:)horia. It may be accepted as a general fact, how- ever, that the symptoms of exophoria are more likely to be local, those of esophoria more general. The effort made in exophoria to hold the visual lines in ad- justment for reading or other close work results in local fatigue and pain. That made in esoi:)horia is attended with less local strain at the moment, but is a perpetual source of disturbance of the relations be- tween the accommodative and converging forces. It is a condition of nervous perplexity, experienced both when looking at near and far i)oints. In the diagnosis of all these conditions of hyper- phoria, esophoria, and exophoria, we are in every case to take into account the fact that the manifest condi- tion does not always represent the absolute deviating tendency. SUPPLEMENT. 213 Graefe, and many who have followed him, regarded insuflBciency of the interni as a condition found mostly with cases of considerable myopia. If we accept the test at the near point as indicating such insufficiency, it may be true that the condition is so frequent with myopia as to be peculiarly an associated state ; but exophoria as here described is less frequently found with myopia than is esophoria. In the condition of orthophoria the adducting power should be equal to an ability to overcome prisms amounting to 50°, when the object is placed at the specified distance, twenty feet. Even eyes with well-balanced muscles may not, in the absence of a certain muscular facility, be able to accomplish this at the first trial. A few attempts will generally be re- warded with complete success. In exophoria the ab- ducting power may be much less than this, and when a considerable reduction of this force is associated with exophoria, as shown by the vertical-prism test, it is an additional evidence of the vicious tendency. Insuffi- cient adducting force is not, however, always indica- tive of exophoria, nor is it always an element of ex- ophoria. Indeed, in many cases of very considerable outward deviating tendency, the power of adduction is exercised with remarkable vigor and to the full extent that can be desired. On the other hand, a feeble ab- ducting power may be found where there is no exo- phoria, and where even esophoria of high degree exists. In these cases the failure of abducting power may arise, among other things, from fatigue of the muscles or from disuse. This latter reason is pecul- 214 FUNCTIONAL NERVOUS AFFECTIONS. iarly marked in certain cases of esoplioria. In such cases there has been, during the history of the patient, little need of performing a positive act of adduction. Habitually the external muscles have by severe ten- sion, maintained the parallelism of the visual lines, and when it is required to converge these lines the act is performed, not altogether by the muscular contraction of the interni, but largely by their natural elasticity, acting when the opposing tension of the externi is removed. TREATMENT OF EXOPHORIA. In the condition of insufficient abducting power, such as may be found with moderate exophoria, with no especial deviating tendency, or with esophoria, the adduction may be greatly improved by gymnastic ex- ercises of the interni conducted by the aid of prisms. In these exercises the eyes are required to unite images in overcoming gradually increasing obstacles. A prism of a few degrees, perhaps 10°, is placed, base out, before one of the eyes, while gazing at a lighted candle placed at twenty feet distance, when an effort is at once made to prevent diplopia. As soon as the images are blended, another prism, of per- haps less degree, is placed in the same manner ; the images being united, a stronger prism takes the place of one of those already in place, or one is added to those already in position. Thus, little by little, the eyes are required to overcome prisms until the images can no longer be united. Then all the glasses are re- moved and the process is repeated ; with each repeti- tion something may be gained. The exercise should SUPPLEMENT. 215 not be continued at a single sitting more than five or six minutes, and only a single sitting daily is desirable. By this means the adducting power can, in most cases, be raised after a few exercises to the desired point. It is an interesting fact that in most cases of moderate exophoria, or of no especial heterophoria, the exercise is attended with much more speedy results than in a certain proportion of cases of esophoria. The effect of such exercises upon the eyes is very often extremely salutary. With greater freedom of muscular action comes a sense of relief from nervous strain, which is often of a most gratifying character. Such an exercise is in no way related to the practice sometimes adopted, and which should be condemned, of requiring the patient to gaze for a length of time at a near object. In this latter case the act of accommoda- tion is associated with the convergence of the optic axis, and there is simply an exaggeration of the accustomed strain. In the exercise Vt^ith prisms the accommoda- tion is at rest, and the action of the recti muscles is almost completely dissociated from that of the ciliary muscles. The exercise then selects the muscles to be acted upon. In exoiDhoria of a moderate degree, prisms with the base in may be found useful in reading. It is in this condition, of all the forms of heterophoria, that prisms are most likely to prove of any permanent use. In general, even for moderate exophoria, a radical relief is to be preferred to the perpetual employment of glasses. The method for performing tenotomy, as described 15 216 FUNCTIONAL NEEVOUS AFFECTIONS. already, should be followed closely in tMs as in other conditions of heterophoria. The advice given by Graefe, and followed up to the present time in the text-books, to sever the externus completely and to induce homonymous diplopia, is not to be followed, Graefe performed his operations, for the most part, in cases of extreme myopia. In these cases, the vision of his patients being defective at a distance, an insuffi- ciency of the extern! did not appear to be a matter of serious consequence. It may well be supposed also that, for the most part, his cases were not of the class which has here been described as exoj)horia, but cases of positive but slight strabismus. The result of a tenotomy for exophoria should not be homonymous diplopia, nor even esophoria to ex- ceed 1° or 2°, and the abducting power should im- mediately after the operation not be less than suffi- cient to overcome a prism of 6°. Should exophoria again manifest itself, the operation may be made upon the opposite eye ; and it is better to make repeated operations than in any instance to obtain diplopia or considerable esophoria. The study of muscular anomalies, in which gross deviations are found, strabismus concomitans, or stra- bismus from paralysis, constitutes a subject of much interest to the student of the effects of ocular anoma- lies upon the nervous system. Cases of this class are much less frequent than those already discussed, and, to a considerable extent, the princiiDles which have been laid down respecting the more ordinary class of anomalies will apply to non-paralytic strabismus. SUPPLEMENT. 217 It is the purpose of tMs supplement only to intro- duce tlie practitioner into a field not usually investi- gated, except by specialists, and to assist liim in his efforts to find and to remove a class of causes largely instrumental in inducing an important class of dis- orders. To add largely to what has been said would be out- side the design of this work. The author, therefore, reserves the discussion of his personal views upon strabismus for a future work upon the ocular muscles. THE EJS^D. An Atlas of Clinical Microscopy. By ALEXANDER PETER, M. D. Translated and edited by Alfred C. GiRAED, !M. D., Assistant Surgeon United States Army. First American, from ttie Manuscript of the second German edition, with Additions. Ninety Plates, with One Hundred and Five Illustrations, Chromo-Lithographs. Square 8vo volume. Cloth, $6.00. " All who are interested in clinical microscopy will be pleased with the design and execution of this work, and will feel under obligation to the author, trans- lator, and publishers for placing so valuable a work in their hands. The plates in which are figured the various urinary inorganic deposits are especially fine, and the various forms of tube-casts, hyaline, waxy, epithelial, and mucous, are depicted with great fidelity and accuracy." — Philadelphia Medical Times. " To those students and practitioners of medicine who are interested in micro- scopical work and who are familiar with the use of this valuable aid to human vision in the study of nature, the present work will prove of incalculable value, since it represents the original work of an accomplished microscopist and artist. Accompanying the plates is a text of explanatory notes showing the various methods of working with the microscope and the significance of what is observed. The plates have been most handsomely printed. We have seen nothing in this special line of study that will compare in point of accuracy of detail and artistic effect to the work under consideration." — Maryland Medical Journal. The Use of the Microscope in Clinical and Pathological Examinations. By Dr. CARL FRIEDLAENDER, Privat-Docenfc in Pathological Anatomy in Berlin. Translated from the enlarged and improved second edition, by Henet C. Coe, M. D., etc. With a Chromo-Lithograph. 12mo, 195 pages, with copious Index. Cloth, $1.00. "We are very much pleased to see Dr. Friedlaender's little book make its appearance in English dress. As we have a practical acquaintance of the Ger- man edition since its appearance, we can speak of it in terms of unqualified praise. . . . Every one doing pathological work should have this httle book in his possession. The translator has done his work well, and has certainly conferred a great favor on all microscopists by placing within the reach of every one the work of so accomplished a teacher as Dr. Carl Friedlaender." — Canada Medical and Surgical Journal. " Much good has been done in placing this little work in the hands of the profession. The technique of preparing, cutting, and staining specimens is given at some length ; also rules for the examination of the various bodily fluids in both health and disease. The use of the microscope with high powers, immer- sion lenses, and other accessories, is explained very clearly. It is a very readable volume, even for those not engaged in actual laboratory work. A chromo-litho- graph shows the various forms of disease-germs which have been definitely iso- lated." — Medical Record. New York : D. APPLETON & CO., 1, 3, & 5 Bond Street. A TREATISE ON INSANITY, IN ITS MEDI- CAL RELATIONS. By WILLIAM A. HAMMOND, M. D., Surgeon-General TJ. S. Army (retired list) ; Professor of Diseases of the Mind and Nervous System, in the New York Post-Graduate Medical School ; President of the American Neurological Association, etc. 1 vol., 8vo, 767 pp. Cloth, $5.00 ; sheep, $6.00. In this work the author has not only considered the subject of Insanity, but has prefixed that division of his work with a general view of the mind and the several categories of mental faculties, and a full account of the various causes that exercise an influence over mental derangement, such as habit, age, sex, hereditary tendency, constitution, temperament, instinct, sleep, dreams, and many other factors. Insanity, it is believed, is in this volume brought before the reader in an origi- nal manner, and with a degree of thoroughness which can not but lead to impor- tant results in the study of psychological medicine. Those forms which have only been incidentally alluded to or entirely disregarded in the text-books hitherto pub- lished are here shown to be of the greatest interest to the general practitioner and student of mental science, both from a normal and abnormal stand-point. To a great extent the work relates to those species of mental derangement which are not seen within asylum walls, and which, therefore, are of special importance to the non-asylum physician. Moreover, it points out the symptoms of Insanity in its first stages, during which there is most hope of successful medical treatment, and before the idea of an asylum has occurred to the patient's friends. A TREATISE ON THE DISEASES OF THE NERVOUS SYSTEM. By WILLIAM A. HAMMOND, M.D., Surgeon-General U. S. Army (retired list) ; Professor of Diseases of tlie Mind and Nervous System, in the New York Post-Graduate Medical School ; President of the American Neurological Association, etc. Seventh edition, rewritten, enlarged, and improved. In one large 8ro vol. of 929 pp., with Complete Index and 150 lUmtrations. Cloth, $5.00 ; s/uep or half russia, $6.00. The work has received the honor of a French translation by Dr. Labadlc- Lagrave, of Paris, and an Italian translation bv Professor Diodato Borrelli, of the Eoyal University, is now going through the press at Naples. ". '™™°° ^^'"^ ^^^ °°^ ^^'^^ ^°^^ experience is larore, his convictions before tlie profession for many years, are positive, and he can set them forth and Its characteristics are verv generally cleariy and attractively. It Ls not surpris- known. The present edition has a good ing that his book has been a very popu- quaUties of a successful author. His prac- New York: D. APPLETON & CO., 1, 3, & 5 Bond Street. A PRACTICAL TREATISE ON MATERIA MEDICA AND THERAPEUTICS. By ROBERTS BAETHOLOW, M. A., M. D., Professor of Materia Medica and Therapeutics in the Jefferson Medical College, etc. Fifth edition. Bevised, enlarged, and adapted to " The New Pharmaccpaia:' 1 vol., 8vo. Cloth, $5.00 ; sheep, 86.00. From Peeface to Fifth Edition. " The appearance of the sixth decennial revision of the ' United States Pharmacopoeia ' has imposed on me the necessity of preparing a new edi- tion of this treatise. I have accordingly adapted the work to the official standard, and have also given to the whole of it a careful revision, incor- porating the more recent improvements in the science and art of thera- peutics. Many additions have been made, and parts have been rewritten. These additions and changes have added about one hundred pages to the body of the work, and increased space has been secured in some places by the omission of the references. In the new material, as in the old, prac- tical utility has been the ruling principle, but the scientific aspects of therapeutics have not been subordinated to a utilitarian empiricism. In the new matter, as in the old, careful consideration has been given to the physiological action of remedies, which is regarded as the true basis of all real progress in therapeutical science; but, at the same time, I have not been unmindful of the contributions made by properly conducted clinical observations." " He is well known as a zealous student pape. Dr. Bartholow, like another expe- of medical science, an acute observer, a ricnccd teacher — Professor von Schroff, of gfood writer, a skilled practitioner, and an Vienna — picks out the most important ingenious, bold, though sometimes reck- physiological and therapeutical actions of less investigator. His present book will each drug, and gives them in a short and receive the cordial welcome which it de- somewhat dogmatic manner. Having serves, and which the honorable position formed his own conclusions, he gives that he has won entitles him to demand them to the public, without entering so for it. . . . Dr. Bartholow's treatise has fully as Wood into the experiments on the merit — and a great merit it is— of in- which they are founded." — IVaditioner cludincr diet as well as drugs. . . . His {London). ^^^. ^f'ti ^°n ^^Vo.^e or depreciate the » ^ ^ ;t ^^^ ^^^^ Dr. itZ^l^ . ^ ^T'"'f^ ^"f ' •''* ? '"''"■ Bartholow has, to a great extent, succe.s- S.Z -^ f '■'V^'°''''^ profes..ional expe- ^^j, ^ ^^ ^.'j^^ ^^^ difficulties of his tW^^ri.V-. 1 ''^"' n^^'^\}^ ^^^^^^ classification, and his book has also other tW,-r rfw^ni • Tl'T "■ ^?J"^^/^ "P°'^ merits to commend it. It is largely origi- J^?.VLP;Ti^" ?/^'^^e^ nal. By this we mean that it gives tie Journal of the Medical Sciences. ^^^^^^^ ^^^ ^^^ ^^^^^^,^ ^^^ ^^^j^ „^i " After looking through the work, observation, instead of a catalogue of the most readers will agree with the author, contending statements of his predeces- whose long training shows itself on every sors." — Tlie Doctor {London). New York : D. APPLETON & CO., 1, 3, k 5 Bond Street. A TREATISE ON THE PRACTICE OF MEDI- CINE, for the Use of Students and Practitioners. By EOBEETS BAETHOLOW, M. A., M. D., LL. D., Professor of Materia Meclica and General Therapeutics in the Jefferson Medical Col- lege of Philadelphia ; recently Professor of the Practice of Medicine and of Clinical Medicine in the Medical College of Ohio, in Cincinnati, etc., etc. Fifth edition, revised and enlarged. 8vo. Cloth, $5.00 ; shee^ or half rusiia, $6.00. The same qualities and characteristics which have rendered the author's " Trea- tise on Materia Medica and Therapeutics " so acceptable are equally uianitcst in this. It is clear, condensed, and accurate. The whole work is brought up on a level with, and incorporates, the latest acquisitions of medical science, and may be depended on to contain the most recent information up to the date of publicatioa. " Probably the crowning feature of the work before us, and tliat which will make it a favorite with practitioners of medi- cine, is its admirable teaching on tlie treat- ment of disease. Dr. Bartliolow has no sympathy with the modern school of ther- apeutical nihilists, but possesses a whole- some belief in the value and efficacy of remedies. He does not fail to indicate, however, that the power of remedies is limited, that specifics are few indeed, and that routine and reckless medication are dangerous. But throughout the eutire treatise in connection with each malady are laid down well-defluod methods and true principles of treatment. It may bo said with justice that this part of the work rests upon thoroughly scientific and prac- tical priaciples of therapeutics, and is ex- ecuted in a masterly manner. No work on the practice of medicine with which we are acquainted will guide the practitioner in all the details of treatment so well as the one of whicli we are writing." — Amer- ican Practitioner. " The work as a whole is peculiar, in that it is stamped with the individuality of its author. The reader is made to feel that the e.viJerience upon which this work is based is real, that the statements of the writer are foimded on firm convictions, and that throughout the conclusions are eminently sound. It is not an elaborate treatise, neither is it a manual, but half- way between ; it may be considered a thoroughly useful, trustworthy, and prac- tical guide for the general practitioner." — Medical Record. " It may be said of so small a book on so large a subject, that it can be only a sort of compendium or vade mecum. But this criticism will not be just. For, while the author is master in the ait of conden- sation, it will be found that no essential points have been omitted. Mention is made at least of every unequivocal symp- tom in the narration of the signs of dis- ease, and characteristic symptoms are held well up in the tbregroimd in every case." — Cincinnati Lancet and Cli?iic. " Dr. Bartholow is known to be a very clear and explicit ■writer, and in this work, which we take to be his special life-work, we are very sure his many friends and ad- mirers will not be disappointed. 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UNIVERSITY OF CALIFORNIA LIBRARY Los Angeles This book is DUfcoH the last date^stainped below. m 2676 %, fo "0 J UN 2 1 1988 REC'D BIDMEP MAY 1 ? MAY 1 3 1987 SiOMEDpj^^.^l '87 jUN 1 6 1988 ^14/3 9 'B7 3 115