Evaluation of a new digital visual acuity chart for best‐corrected visual acuity estimation

Abstract

AbstractPurposeTo compare estimated best‐corrected visual acuity (BCVA) between the digital chart named AxAnIvIs and the ETDRS chart at different level of acuity, and to determine if there is difference of the test time between the two systems.MethodsPatients at the eye clinic of Uppsala university hospital that met the inclusion criteria (age >55 years, BCVA [1.0; −0.1] and no ocular disease strongly considered to cause visual acuity change within one month) were asked to participate this study. The AxAnIvIs system uses a custom made algorithm for optotypes visualisation where optotypes decrease in size horizontally in one line. Altogether 16 subjects (8 male, 8 female) were included and distributed equally to four visual acuity classes ([1.0 0.8], [0.7 0.5], [0.4 0.2], [0.1 −0.1] logMAR). Each subject’s BCVA was measured and the test time was recorded with the two systems on two separate occasions.ResultsThe mean BCVA difference between the AxAnIvIs system and the ETDRS chart at visual acuity class of [1.0 0.8], [0.7 0.5], [0.4 0.2], [0.1 −0.1] logMAR was estimated as a CI(95%), 0.02 ± 0.04, 0.02 ± 0.08, ‐0.01 ± 0.05, 0.03 ± 0.07 logMAR, respectively. ANOVA shows that there is no significant difference between the two systems and no significant difference between the two systems at the different visual acuity classes. The mean test time between the AxAnIvIs system and the ETDRS chart was estimated as a CI(95%), −37 ± 15 s.ConclusionsThe AxAnIvIs system can be used as a replacement of the ETDRS chart for general examination. The test time with the AxAnIvIs system is half minute shorter than that with the ETDRS chart.