EVALUATION OF NIGHT-VISION DISTURBANCES

BACKGROUND: Evaluation of night vision disturbances has relied on subj ective responses. We designed a test to more objectively measure night vision disturbances. METHODS: The test consisted of projecting a smal l circle onto a visual acuity screen. The patient is asked to draw exa ctly what he sees on an Amsler grid. We evaluated 118 eyes in photopic and scotopic conditions and under different conditions of refractive correction. RESULTS: Image degradation increased in scotopic condition s for myopes (p = .0001), hyperopes (p = .005), and emmetropes (p = .0 1). Myopic refractive error correlated with size of glare response (p = .001). Astigmatism correlated with decentration of glare response (p = .0001). Decentration increased in scotopic compared to photopic con ditions (p = .002). CONCLUSION: Our test offers a simple, convenient w ay to evaluate night vision disturbances and may offer a means of asse ssing night vision disturbances in patients considering refractive sur gery.