Measurement of distance objective visual acuity with the computerized optokinetic nystagmus test in patients with ocular diseases

To evaluate the efficacy of a computerized optokinetic nystagmus (OKN) test for determination of objective visual acuity (VA) at distance in patients with various ocular diseases. This is a prospective, non-interventional study that included 85 eyes of 71 patients with one or more ocular pathologies. Study patients were classified into group C (39 eyes of 30 patients with central visual damage), group P (24 eyes of 20 patients with peripheral visual defect) and group M (22 eyes of 21 patients with media opacity). Objective distance VA was measured with OKN induction and suppression methods, and the correlation between the objective and subjective VA at distance was evaluated using linear regression analysis. Mean subjective VAs were compared among each objective VA step and among the three groups. Significant correlation was found between subjective distance VA and objective VA determined by both OKN induction and suppression methods in all three groups and in overall patients. In overall patients, the mean subjective VA was significantly different in several objective VA steps (Welch's ANOVA, p < 0.001 for induction and suppression methods). No significant difference in subjective VA among the three groups was found in any objective VA step. Our objective VA test using OKN induction and suppression methods can be useful in estimating distance VA in patients with various ocular diseases.