IMPACT OF HEADLIGHT GLARE ON PEDESTRIAN DETECTION WITH UNILATERAL CATARACT.

Abstract

Detecting pedestrians while driving at night is difficult, and is further impeded by oncoming headlight glare (HLG). Cataracts increase intraocular light scattering, making the task even more challenging. We used a within-subjects repeated measures design to determine the impact of HLG on driving with unilateral cataract. Pedestrian detection performance of six young normal vision (NV) subjects was measured with clear lens glasses and with simulated unilateral cataract (0.8 Bangerter foil) glasses. The subjects drove night-time scenarios in a driving simulator with and without custom simulated headlight glare. With simulated unilateral cataracts, pedestrian detection rates decreased and response times increased with oncoming HLG. We verified these effects with six patients who already underwent cataract surgery for one eye and were scheduled to get cataract surgery in the other eye. We measured their performance before and after the second cataract surgery. The results were similar to those obtained with the simulated unilateral cataract, confirming that a negative impact of HLG persists with untreated cataract in one eye.