Efficacy of a computerized optokinetic nystagmus test in prediction of visual acuity of better than 20/200.

PURPOSE

To evaluate the efficacy of a computerized optokinetic nystagmus (OKN) test in detecting visual acuity (VA) of >20/200.

METHODS

This was a combined retrospective and prospective, noninterventional study. In phase I of the study, data from 168 eyes of 154 subjects who underwent the computerized objective VA test using OKN responses at Seoul National University Bundang Hospital were reviewed and reanalyzed, and a table for predicting the range of subjective VA for each step of objective VA was made. From the table, the cutoff value for detecting VA of >20/200 was determined. In phase II of the study, the distribution of subjective VA according to each objective VA step was determined for 80 eyes of 40 subjects at Seoul Veteran's Hospital. The sensitivity and the specificity of our cutoff value were evaluated in the two groups.

RESULTS

No significant difference was found in the distribution of subjective VA according to objective VA steps between the two groups. For the subjects in phase I of the study, the sensitivity of our cutoff value was 91.7% and the specificity was 88.3%. For patients in phase II of the study, the sensitivity of our cutoff was 86% and the specificity was 96.7%.

CONCLUSIONS

This study shows that an objective VA test using OKN responses can be effective in predicting real VA and detecting VA of >20/200.