The Philippine Peso Bill as an Alternative Near Visual Acuity Chart in Filipino Eyes: A Pilot Study

Abstract

Purpose: This study aimed to determine if near visual acuity measurements using a Philippine peso bill are comparable to a standard Jaeger chart.

Study design: This is a cross-sectional study comparing the near visual acuity measurements of a Philippine peso bill and a Jaeger chart among sixty subjects.

Methods: LogMAR scores from the two methods were analyzed using Wilcoxon Mann-Whitney test. The relationship of the logMAR scores between these methods was determined using Spearman rank order correlation. The Bland-Altman plot was used to determine the comparability between quantitative measurements for near visual acuity using the standard Jaeger chart (reference) and the Philippine peso bill.

Results: There were no significant differences in the proportion of Jaeger scores and mean logMAR equivalents between the two methods (p > 0.05). The scatter plot diagram shows a positive upward trend with a very strong and significant correlation between logMAR scores of Jaeger chart and Philippine peso bill methods (r = 0.9258, p < 0.0001). With a concordance correlation coefficient of 0.9505, there is a high agreement between these two measures. The Philippine peso bill overestimates the Jaeger chart visual acuity by 0.04 logMAR units. We suspect that the contrast between the background color and the serial numbers of the peso bill may have brought about this outcome.

Conclusion: The Philippine peso bill may be used as an alternative measuring tool for near visual acuity. However, there is a tendency to overestimate the scores obtained using the Philippine peso bill. Future studies are recommended to validate the results in a tele-ophthalmology setting.

Keywords: Jaeger chart; near vision; near visual acuity testing; tele-ophthalmology; telemedicine.