Older drivers' self-reported vision-related night-driving difficulties and night-driving performance

Purpose: To investigate associations between older drivers' perceived vision-related night-driving difficulties and night-time driving performance measured on a closed-road circuit. Methods: Participants included 26 older drivers (71.8 ± 6.3 years) who reported vision-related night-driving difficulties assessed with the vision and night driving questionnaire (VND-Q). High-contrast, photopic visual acuity (VA) and ratings of discomfort glare (de Boer scale) were also assessed. Night-time driving performance was measured on a closed-road circuit that involved recognition, hazard avoidance and lane-keeping tasks in the absence and presence of intermittent glare. Generalized linear mixed models investigated the relationship between VND-Q scores and overall driving performance scores, as well as with discomfort glare ratings and VA. Results: Greater levels of vision-related night-driving difficulties (VND-Q scores) were significantly associated with poorer night-driving performance (p = 0.003); the association was even stronger for driving performance in the presence of intermittent glare (p = 0.001). Reduced VA was associated with poorer night-driving performance (p = 0.022) but the association was weaker than for the VND-Q scores. In contrast, ratings of discomfort glare were not significantly associated with driving performance (p = 0.14). Conclusion: The VND-Q was significantly associated with night-time driving performance and provides a useful instrument for assessing vision-related night-driving difficulties which can be incorporated into clinical vision assessments.