Comparison of Visual Acuity Measurement Using Three Methods: Standard ETDRS Chart, Near Chart and a Smartphone-Based Eye Chart Application

Abstract

Purpose To validate the Rosenbaum near vision card (Near Chart) and a smartphone-based visual acuity (VA) test (Eye Chart) against a standard retro-illuminated Early Treatment Diabetic Retinopathy Study (ETDRS) chart within participants. Materials and Methods A cross-sectional study of participants aged ≥18 years was conducted. VA was measured in all participants using the ETDRS chart, Near Chart and smartphone-based Eye Chart application, respectively. VA was converted to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. Eyes with ETDRS VA worse than 1.0 logMAR (20/200) were excluded. The main outcome measures were levels of agreement between VA measured using the Near Chart or Eye Chart application vs the ETDRS chart. Results A total of 295 eyes of 151 participants were included. One hundred participants (66.2%) were female and the mean age was 64.3 ± 12.5 years. Educational level was high school or below for 49% of participants and at Bachelor’s degree or above for 51%. The median logMAR VAs of all eyes tested using the ETDRS chart, Near Chart and Eye Chart application were 0.1, 0.0 and 0.1, respectively. The median VA difference between the Near Chart vs ETDRS chart and Eye Chart application vs ETDRS chart was 0.0 logMAR in both cases for both the right eye (OD) and left eye (OS). Intraclass correlation coefficient (ICC) demonstrated a strong positive correlation between VA tested with the Near Chart vs ETDRS chart (OD: ICC=0.85; p <0.001, OS: ICC=0.77; p <0.001) and Eye Chart application vs ETDRS chart (OD: ICC=0.88; p <0.001, OS: ICC=0.74; p <0.001). Conclusion VA measurements with the Near Chart and smartphone-based Eye Chart application corresponded well to the standard ETDRS chart, suggesting potential utility of alternative portable VA tests for in-office or remote vision monitoring, particularly during periods of physical distancing such as the Coronavirus disease 2019 (COVID-19) era.

The Impact of COVID-19 on Diabetic Retinopathy Monitoring and Treatment

“…The COVID-19 pandemic has also highlighted the need for telemedicine in diabetic retinopathy screening and monitoring. Patient self-screening, which has been shown to be effective using the near card [35] and Alleye program [36], may help optimize prioritization protocols for clinic visit and intravitreal injections. Moreover, telescreening using fundus photography and artificial intelligence-based classification of diabetic retinopathy have demonstrated high specificity and sensitivity in diagnosing diabetic retinopathy [37][38][39].…”

A Smart Mobile Application to Monitor Visual Function in Diabetic Retinopathy and Age-Related Macular Degeneration: The CLEAR Study

“…Other mobile applications are currently being used to monitor visual function, such as the King-Devick Variable Color Contrast Sensitivity Chart (VCCSC), which checks the discernment of low levels of contrast for the early detection of AMD, 15 and the smartphone-based Eye Chart application, which has been shown to correspond well to the EDTRS chart for VA tests. 16 Together, these apps and others have the potential to improve monitoring, which could ultimately impact outcomes.…”

The Influence of Visual Input on Electromyographic Patterns of Masticatory and Cervical Spine Muscles in Subjects with Myopia

“…The current gold standard for measuring visual acuity in clinical practice and research has been used. That is the back-lit logarithm of the minimum angle of resolution (logMAR) and it was used in the Early Treatment Diabetic Retinopathy Study (ETDRS) [24]. Visual acuity testing using the ETDRS card was performed from a distance of 4 m. Each line of the graph contains five optotypes, and their size varies by a constant proportion in each line [24].…”

“…That is the back-lit logarithm of the minimum angle of resolution (logMAR) and it was used in the Early Treatment Diabetic Retinopathy Study (ETDRS) [24]. Visual acuity testing using the ETDRS card was performed from a distance of 4 m. Each line of the graph contains five optotypes, and their size varies by a constant proportion in each line [24]. This study was conducted by an experienced medical doctor specializing in eye diseases (author A. M.-W.).…”