Purpose:
To investigate the visual function correlates of
self-reported
vision-related night driving difficulties among
drivers.
Methods:
One hundred and seven
drivers (age 46.06 ± 8.24,
visual acuity [VA] of 0.2logMAR or better) were included in the study. A standard
vision and night driving
questionnaire (VND-Q) was administered. VA and
contrast sensitivity were measured under photopic and mesopic conditions. Mesopic VA was remeasured after introducing a peripheral
glare source into the participants' field of view to enable computation of disability
glare index.
Regression analyses were used to assess the
associations between VND-Q scores, and visual function
measures.
Results:
The mean VND-Q score was -3.96±1.95 logit (interval scale score 2.46±1.28). Simple
linear regression models for photopic
contrast sensitivity, mesopic VA, mesopic
contrast sensitivity, and disability index significantly predicted VND-Q score (P<0.05), with mesopic VA and disability
glare index
accounting for the greatest variation (21 %) in VND-Q scores followed by photopic
contrast sensitivity (19 %), and mesopic
contrast sensitivity (15 %). A multiple regression model to determine the
association between the predictors (photopic
contrast sensitivity, mesopic VA, mesopic
contrast sensitivity, and disability index) and VND-Q score yielded significant results, F (4, 102) = 8.58, P < 0.001, adj. R2 = 0.2224. Seeing dark-colored
cars was the most challenging
vision task.
Conclusion:
Changes in mesopic
visual acuity, photopic and mesopic
contrast sensitivity, as well as disability
glare index are associated with and explain night driving-related visual difficulties. It is recommended to incorporate measurement of these visual functions into assessments related to driving performance.(AU)
