• Teleophthalmology: Home VA Test?

    By Jean Shaw
    Selected By: Emily Y. Chew, MD

    Journal Highlights

    Ophthalmology Science, March/April 2021

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    Although the pandemic has furthered the expansion of teleophthalmology, the inability to remotely assess visual acuity (VA) continues to present a chal­lenge. Siktberg et al. hypothesized that a home VA test, using a printed ETDRS chart, would be equivalent to an in-of­fice ETDRS test performed in the clinic by a trained technician. They found that the home test was equivalent.

    For this prospective cohort study, the researchers enrolled 108 patients (209 eyes) who had scheduled in-per­son eye examinations at the Vanderbilt Eye Institute. Participants were between 19 and 83 years old (mean, 52 years) and had a documented prior BCVA better than 20/200 in both eyes. None of the exams involved postsurgical checkups, and all participants spoke English as their primary language.

    For part 1 of the study, participants were electronically sent a PDF docu­ment consisting of instructions and an ETDRS vision chart calibrated for 5 feet. The patients completed this test at home. For part 2, during the in-person appointment, a trained ophthalmic technician measured the patients’ VA, using a standard ETDRS chart calibrated for 4 meters. The technician also administered a survey on the ease of self-testing at home. The primary outcome was the mean adjusted letter score difference between the two tests. Secondary outcomes included respons­es to the survey questions.

    The mean ETDRS letter scores at home and in the clinic were 75 ± 11 letters (20/32 Snellen equivalent) and 79 ± 11 letters (20/26), respectively. The difference in letter score was 3.9 ± 5.8 letters (90% confidence interval [CI], 3.1-4.7 letters). The mean adjusted VA letter score difference was 4.1 letters (90% CI, 3.2-4.9 letters). As these val­ues were within the study’s prespecified 7-letter equivalence margin, the home test was considered equivalent to the clinic test in this cohort.

    With regard to ease of use, 98% of the participants agreed or strongly agreed that the test was easy to set up and perform. Fewer than 5% of partici­pants reported any barriers to use, such as access to technology and clarity of instructions.

    The authors noted that patients who are familiar with and have access to computers may have been more likely to participate. In addition, non–English speaking patients and those whose VA was worse than 20/200 were excluded, thus limiting the generalizability of the findings. Ideally, future studies would test the validity of a VA test in other patient populations, the authors said. They added that the test should not be used to replace an in-person assessment when that is indicated but rather used to delay well visits or as a tool that en­hances the value of teleophthalmology visits.

    The original article can be found here.