Comparison of smartphone application-based visual acuity with traditional visual acuity chart for use in tele-ophthalmology

Abstract

PURPOSE: The aim of this study was to compare the visual acuity (VA) by smartphone-based applications – EyeChart and the Peek Acuity to the standard Snellen chart to explore the possibility of using them as an alternative in tele-ophthalmology in the current COVID-19 pandemic. MATERIALS AND METHODS: An analytical type of observational study was done on 360 eyes of 184 patients above 18 years of age. Patients with VA <6/60 and gross ocular pathology were excluded from the study. VA measured by these three methods was converted to logMAR scale for ease of statistical analysis. One-way analysis of variance with post Tukey HSD was used to compare the VA measured by these three methods. RESULTS: There was no statistically significant difference between VA measured using the smartphone-based apps (EyeChart and Peek Acuity) and the Snellen chart (F = 2.5411, P = 0.7925) in 360 eyes assessed. VA measured by Peek Acuity (P = 0.5225) was more comparable to Snellen chart than EyeChart (P = 0.4730). Intraclass correlation coefficient (ICC) demonstrated a strong positive correlation for EyeChart (ICC: 0.982, P < 0.001) and Peek Acuity (ICC: 0.980, P < 0.001) with Snellen chart. A Bland–Altman difference plot showed good limits of agreement for both EyeChart and Peek Acuity with Snellen chart. In subgroup analysis, VA measured by Peek Acuity was not statistically different from Snellen in any subgroups, but in EyeChart, it was statistically different in emmetropes. CONCLUSION: VA measured by smartphone apps (EyeChart and Peek Acuity) was comparable with traditional Snellen chart and can be used as an effective, reliable, and feasible alternative to assess VA in tele-ophthalmology.

Keywords

• eyechart
• peek acuity
• smartphone
• tele-ophthalmology
• visual acuity