A new Gujarati language logMAR visual acuity chart: Development and validation

Aims: Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR) visual acuity chart in the Gujarati language. Materials and Methods: A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carried out using 153 adult subjects in a large clinical setting in India. Subjects who were literate in English and Gujarati participated in the study. Visual acuity was measured with the new Gujarati logMAR chart and a modified Early Treatment of Diabetic Retinopathy Study-(m-ETDRS) logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Gujarati logMAR chart. Results: The Gujarati chart correlated highly with the m-ETDRS logMAR chart (r(2) = 0.974). The mean visual acuity difference (Gujarati - m-ETDRS logMAR) was equal to three letters (-0.06 logMAR). The Gujarati logMAR chart also proved to be highly repeatable (r(2) = 0.994, test-retest) with 95% CI of +/- 0.04 logMAR. Conclusions: The new Gujarati logMAR visual acuity chart provides a valid and repeatable tool for the measurement of visual acuity in native Gujarati language speakers.