Measures of visual function and their association with driving modification in older adults

Abstract

Purpose: Older drivers may place restrictions on their driving by reducing their mileage and avoiding high-risk driving situations in an effort to improve safety. This project identifies what types of visual function loss are associated with subsequent driving modifications.

Methods: Data were used from the baseline and 2-year follow-up rounds of the Salisbury Eye Evaluation project, a cohort study of 2520 older adults. Measures of visual function tested were visual acuity, contrast sensitivity, visual fields, and glare sensitivity. Driving information was self-reported. Among drivers at baseline who continued to drive at follow-up, multiple logistic regression was used to estimate the odds of incident driving modification by visual function status.

Results: Worse baseline scores in acuity, contrast sensitivity, and central and lower peripheral visual fields were individually associated with an increased odds of reduced mileage 2 years later (linear trend P < 0.05). Worse baseline scores in contrast sensitivity and central and lower peripheral visual fields were individually associated with a greater odds of cessation of night driving 2 years later, whereas worse baseline acuity scores were associated with an increased odds of cessation of driving in an unfamiliar areas 2 years later (linear trend P < 0.05).

Conclusions: Older drivers with worse visual function were more likely to modify their driving by reducing mileage and avoiding high-risk driving situations. Furthermore, these modifications to driving differed depending on what type of visual function was affected.