key: cord-1042702-x9evgsh9 authors: Miller, Joseph M.; Jang, Hyun Soo; Ramesh, Divya; Gonzalez Marshall, Maria Sandra; Yescas, Selenne; Harvey, Erin M. title: Telemedicine distance and near visual acuity tests for adults and children date: 2020-07-30 journal: J AAPOS DOI: 10.1016/j.jaapos.2020.06.003 sha: 2577559316377dd395d7c31522f55c9251d272bd doc_id: 1042702 cord_uid: x9evgsh9 nan We describe a set of distance and near, adult and child, visual acuity tests for home use. The five charts are packaged in a PDF document and are also available as JPEG images that can be printed on standard letter paper or displayed on a monitor or handheld device. Adult distance visual acuity is tested using a modified ETDRS Chart R; child distance vision is tested using a similarly formatted HOTV logMAR chart. Testing distance is 5 or 10 feet, appropriate for home use. Near visual acuity is displayed in the range of J16 to J1 using random words (for adults) or in HOTV matching format (for young children). An Amsler Grid and HOTV matching card are included. The charts include a calibration circle. For those without a printer, sending a JPEG image as an email attachment initiates onscreen testing with a single click. Devices with smaller screens require an assistant to scroll through the display. The test can performed without assistance from a printed page. The ETDRS logMAR chart represents the gold standard in visual acuity testing, 1 but the testing distance (20 feet) and large chart size (approximately 24 × 24 in) are impractical for display on either ANSI letter-size paper (8 ½ × 11 inches) or conventional electronic displays. Linear optotype presentation of five symbols per line requires a large display. Visual acuity testing of young children is best performed with symbols that are left-right symmetric. For shy or preverbal children, using a matching card avoids requiring the child to name the symbol. 2 Our charts were developed for a shorter testing distance (5 or 10 feet), appropriate for home use. This presents a line of 5 20/200 optotypes in landscape mode on letter paper. Conventional laser printers and flat screen displays found on mobile phones, tablets, laptop or desktop computers have sufficient pixel density for legible 20/16 symbols to be displayed at a testing distance of 5 feet. The 5-foot testing distance does have the disadvantage of being "in from infinity" approximately 1.5 meters, which can result in an individual with uncorrected myopia of 0.75 D being able to read the 20/20 line. At a testing distance of 10 feet, this potential for error drops to 1/3 D. At a testing distance of 20 feet, the error drops to approximately 1/8 D. Thus, a longer test distance decreases the potential for error, whereas a shorter distance improves testability of young children. 3 The design of the HOTV logMAR chart follows the design principles of the ETDRS chart: one letter is duplicated per line, duplicate symbols are not adjacent within a line, and all four letters appear as duplicates an equal number of times throughout the chart. The optotypes for the ETDRS and HOTV charts were rendered using rasterizing software developed for electronic displays 4,5 then converted to scalable vector graphics to allow for device-independent rendering across screen and printer devices. The letter distance chart was printed full size from the PDF file using a 600 dpi laser printer, and a micrometer was used to measure the line heights. Near charts are presented using the size recommendations of Jaeger. 6 For adults, we present three random words at each Jaeger size, and for children we present HOTV letters in logMAR format for use with the HOTV matching card. Holding the chart at the AMArecommended test distance of 14 inches (the diagonal length of letter-sized paper) provides a Snellen fraction. A limitation of both the near and distant charts is that there is no random variation or presentation of the optotypes, even when displayed electronically. Therefore, the tests could be affected by familiarity with the stimuli when testing is repeated (for example, when testing right and left eyes monocularly). The Amsler Grid, used for monitoring macular function, is presented with a black background as described by Amsler rather than with a white background (appearing as a piece of graph paper) as is frequently presented. 7 Augustine and colleagues 8 has shown that Amsler's original design is superior to the more commonly seen black line on white background. Therefore, the original design is presented here. Our goal was to make reliable, home-based acuity measurements available to all our patients, not only the most technologically savvy. English and Spanish Language versions of the tests are available for download at jaapos.org (eSupplement 1 [English] and eSupplement 2 [Spanish]; eSupplement 3 [JPEG files]. The COVID pandemic is increasing the need for teleophthalmology. The most basic ocular vital sign is visual acuity; we hope that this set of charts facilitates this measurement at home. New visual acuity charts for clinical research Vision screening of very young or handicapped children Preschool vision screening tests administered by nurse screeners compared with lay screeners in the Vision in Preschoolers Study A computerized method of visual acuity testing: adaptation of the Early Treatment of Diabetic Retinopathy Study testing protocol Computerized method of visual acuity testing: adaptation of the Amblyopia Treatment Study visual acuity testing protocol Jaeger's test-types (Schrift-Scalen) and the historical development of vision tests Earliest symptoms of diseases of the macula Comparison of the original Amsler grid with the modified Amsler grid: result for patients with age-related macular degeneration