Validation of a self-administered Home ETDRS visual acuity testing (H-ETDRS) for self-monitoring vision changes in retinal diseases

OBJECTIVE: To validate a self-administered Home Early Treatment Diabetic Retinopathy Study (H-ETDRS) visual acuity (VA) test and to assess its accuracy in detecting VA decline in patients with retinal diseases. METHODS: A validation group of 156 participants and a testing group of 100 participants with diabetic retinopathy and age-related macular degeneration were recruited. All participants underwent monocular distance best-corrected VA (BCVA) tests in the study eye using the standard ETDRS (S-ETDRS) charts in clinic and the H-ETDRS device in a simulated home setting. Participants in the validation group repeated both methods. H-ETDRS letter scores were compared with S-ETDRS scores, evaluating mean difference and test-retest reliability (TRR). Intraclass correlation coefficients (ICCs) were calculated to measure the agreement. Participants in the testing group repeated both methods with a Bangerter filter density of 0.6 to simulate BCVA change. The performance of H-ETDRS in detecting acuity change was evaluated, with S-ETDRS serving as the standard. RESULTS: For the validation group, the mean difference between S-ETDRS and H-ETDRS scores was -1.38 letters (95% limits of agreement (LOA) -6.99 to 4.22). The scores of the two tests were highly correlated with an ICC of 0.98. The mean differences between initial test and retest scores were 0.11 letters (95% LOA -2.62 to 2.84) for S-ETDRS and -0.13 letters (95% LOA -5.64 to 5.38) for H-ETDRS. The ICCs of test-retest letter scores were 1.00 for S-ETDRS and 0.98 for H-ETDRS. For participants in the testing group who showed BCVA decline of one line or more with Bangerter filter, 96.7% were able to detect VA changes using H-ETDRS. CONCLUSIONS AND RELEVANCE: The H-ETDRS test demonstrates high TRR and good concordance with S-ETDRS test for retinal patients. The H-ETDRS is viable for self-monitoring VA changes in retinal diseases, however, further validation studies in actual home settings are warranted.