At-home visual acuity tests compare favorably within 1 line of vision to VA measurements performed during a standard office visit.
Kellyn Bellsmith, MD and colleagues from the Casey Eye Institute, Oregon Health & Science University, Portland, OR, found that the results obtained with the use of 3 different types of visual acuity (VA) tests designed to be used at home during the COVID-19 pandemic seemed to compare favorably within 1 line of vision to VA measurements performed during a standard office visit. Those at-home tests included those on a printed chart, a mobile home app, and a website.
The study results1 supported the use of at-home tests during teleophthalmology care. This is important considering the significant drop in in-person VA evaluations during the pandemic.
Dr. Bellsmith and coauthors arrived at their conclusions about the value of at-home VA testing through a randomized, comparative effectiveness research study. During the study, the participants performed the various tests at home and the results were compared with the VA measurements arrived during a follow-up regular clinic examination.
The participants were recruited from 4 university-based ophthalmology clinics from July 2020 to April 2021. All subjects, who had VA levels of 20/200 or better, were randomized to perform 2 of the 3 tests evaluated in their homes during the 3 days before their regular in-office examinations. The subjects then completed an assessment of the usability of the tests. Their VA obtained on the at-home tests were compared with the in-office results.
Results of at-home VA testing
The investigators evaluated the results from 121 subjects (mean age, 63.8 years). The mean VA measured during the in-office visits was 0.11 logarithm of the minimum angle of resolution (logMAR) (Snellen equivalent 20/25). The mean difference expressed in logMAR units between the at-home VA tests and in-office VA tests was −0.07 for the printed chart, −0.12 for the mobile phone app, and −0.13 for the website test, Dr. Bellsmith reported.
One drawback was that older patients were less likely to have access to digital tools, the investigators reported.
The investigators commented, “Compared with in-office acuity measurements, all 3 at-home tests were within 1 line of Snellen acuity.”
They also pointed out that additional development and validation of at-home VA tests are needed considering the expanded use of teleophthalmology care.
Bellsmith KN, Gale MJ, Yang S, et al. Validation of home visual acuity tests for telehealth in the COVID-19 era. JAMA Ophthalmol Published online March 31, 2022. doi:10.1001/jamaophthalmol.2022.0396