Validation of home visual acuity tests for telehealth in the COVID-19 era

Abstract

Purpose : One of the most important clinical data points in evaluating ophthalmology patients is visual acuity (VA). During the COVID-19 pandemic, eye health providers are utilizing telehealth to decrease patient and provider risk related to in-person clinic visits, while still providing high-quality care. This study sought to compare at-home VA tests with in-office clinical VA measurements to determine the validity of at-home VA testing for telehealth visits.

Methods : Patients from 1 comprehensive and 3 subspecialty ophthalmology clinics had VA greater than or equal to 20/200 in the study eye. The patients were prospectively randomized to perform 2 of 3 at-home VA tests (printed chart – University of Arizona/Banner Eye Care Letter Distance Chart; mobile phone app – Verana^TM Vision Test; website test – Farsight.care) within 3 days of their standard of care clinic visit. Patients also completed a survey to assess usability of home tests. At the clinic visit, best corrected Snellen distance acuity was measured to serve as the reference standard.

Results : Of the 44 patients (84 eyes) enrolled, 60% were female and the mean age was 66 years (range 22 to 80). The mean difference between printed chart and Snellen, website test and Snellen, and mobile app and Snellen acuity data was 0.10 (95% CI: 0.09-0.11), 0.13 (95% CI: 0.12-0.14), and 0.12 (95% CI: 0.11-0.13) LogMAR, respectively. The highest degree of correlation was between the website and Snellen tests (0.74, 95% CI: 0.59-0.84) (Table 1).

Patients found the tests easy to perform at home and were neutral regarding confidence in their results and desire to continue with home testing. In the survey, there was no significant difference for between the 3 tests regarding any of the 4 questions (P = 0.32-0.62), although there was a trend toward a more positive response with the printed chart (Table 2).

Conclusions : These data suggest that some at-home visual acuity tests are comparable in accuracy to in-clinic Snellen visual acuity tests (within 1 line of difference). Patient surveys indicated the tests were easy to understand and complete at home. Further development and validation of at-home vision testing modalities are needed to provide accurate and accessible tele-ophthalmology care.

This is a 2021 ARVO Annual Meeting abstract.

 

Table 1. Comparison of at-home and in-clinic acuity tests

 

Table 2. Patient survey responses about at-home tests (5 = “strongly agree”; 4 = “agree”; 3 = “neutral”; 2 = “disagree”; 1 = “strongly disagree”)