Feasibility of Visual Acuity Assessments using the FocalView app at Home and in the Clinic in Patients With nAMD and DME

Abstract

Purpose : To assess the feasibility and performance of using the monocular near visual acuity (nVA) module of the FocalView app in patients with neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME).

Methods : This was an open, non-randomized, multicenter feasibility study. Adults (≥18 years) with nAMD or DME and with best-corrected distance VA (BCDVA) ≥20/200 in the study eye were included. During the in-clinic screening visit, best corrected near VA (BCNVA) and BCDVA were assessed using an ETDRS chart. Participants were instructed on the app use for monocular VA self-assessment with near habitual correction. During the screening period, participants used the app at home at least once a week, to get familiarized with it. After successful screening, participants were assigned to 1 of 3 pre-defined home testing schedules with variations in testing frequency. At the baseline and end of study visits, participants were assessed with the app and both ETDRS charts. Bland-Altman plots with repeated measurements per participant at those two visits were produced to assess the agreement of nVA obtained with the app and with near ETDRS chart.

Results : The mean (SD) age of enrolled participants (n=105) was 66.9 (11.7) years and 47.6% were female. The variability of nVA (LogMAR; min, max) was not notable different, both within (0.08–0.12) and between participant (0.23–0.29) among testing regimens, or by the time of testing during the day (Table 1). There was no difference identified between at-home and in-clinic nVA app measurements. The mean difference of nVA from app measurements at home and from near ETDRS chart was -0.01 LogMAR with limits of agreement (95% CI) at -0.40 (-0.47, -0.35) and 0.39 (0.34, 0.46). Based on a patient feedback questionnaire, 70% of participants could use the app without additional help and 7 of 13 questions scored >6 out of 7 (Table 2).

Conclusions : Majority of nAMD and DME participants could use the FocalView app for self-nVA assessment both at home and in the clinic with a positive experience. The frequency and timing of testing did not definitively affect variability. Agreement of VA obtained with the app and from the standardized in-clinic tests supported the possibility of providing reliable VA data.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.