Accuracy of Mobile-Based Vision Chart in Clinical Practice during the COVID-19 pandemic.

Purpose: The accuracy of mobile-based visual acuity testing in clinical practice is debatable. This study aimed to analyze the accuracy of mobile-based distant vision chart in comparison to the standard chart projector.
Methods: In this cross-sectional study, monocular distant best-corrected visual acuity (BCVA) in 571 eyes of 288 subjects was measured twice, using the Tumbling E vision chart by standard chart projector and repeated using mobile-based vision chart application with screen mirroring on a 22-inch monitor. The decimal results of BCVA were compared to analyze the accuracy of the mobile-based chart in comparison to the standard vision chart projector.
Results: The mean age of the studied patients was 29 ± 14 years. The most frequent refractive error was hyperopia (35.4%), followed by emmetropia (26.7%), myopia (22.9%), and astigmatism (14.9%). The mean BCVA in decimal form was 0.9 ± 0.2 and 0.91 ± 0.26 by the standard and mobile-based charts, respectively. An excellent agreement was reported between both tests as the intraclass correlation coefficient (ICC) was 0.976, with a confidence interval (CI) of 0.965-0.982. Bland-Altman analysis revealed that most visual acuity differences between both methods lie on the equality line or within the allowed difference zone.
Conclusions: The mobile-based vision chart is an economical, accessible, and accurate way for distant vision assessment, and its results are comparable to the standard chart projector in clinical practice.