Refractive blur’s influence on discomfort glare perception from white LED headlights at night

This study examined the effects of refractive blur on discomfort perception caused by peripheral glare from white LED passing (low)-beam headlights at night. The study compared two levels of binocular blur (+0.50 diopter [D] and +1.00<i>D</i>) against a baseline of optimal refractive correction. Thirty participants (mean age 21.3±1.6 years; range 20-24 years) simulating a driving position assessed discomfort from glare sources (headlights of oncoming vehicles) located at 40 and 20 m distances using the de Boer scale. The study found that, with a blur of +0.50<i>D</i>, discomfort glare from white LED headlights did not significantly differ from the baseline regarding de Boer scores. However, with a blur of +1.00<i>D</i>, de Boer scores significantly decreased, indicating increased discomfort glare compared with the baseline for all distances (<i>P</i>=0.004). These results suggest that refractive blur may contribute to an increased perception of discomfort glare during nighttime driving.