Measures of visual function and time to driving cessation in older adults

Purpose. Older adults may place restrictions on their driving once their visual function has become compromised, presumably in an effort to ensure their safety. It is important to identify the types of visual function loss that lead to driving cessation to better understand the relationship between vision and driving. Methods. Data were used from the Salisbury Eye Evaluation project, a cohort study of 2520 older adults followed for 8 years with four rounds of data collection. Multiple measures of visual function were objectively assessed and driving information was collected through self-report from subjects or proxies. Cox regression was used to examine whether those with worse baseline and 2-year change scores in acuity, contrast sensitivity, visual fields, and glare sensitivity were more likely to stop driving after baseline after adjusting for demographic and health variables. Results. Those with worse baseline scores in acuity, contrast sensitivity, central or lower peripheral visual fields were more likely to stop driving (trend p values < 0.05). Also, those who experienced 2-year losses in acuity, contrast sensitivity, or lower peripheral visual fields were more likely to stop driving (trend p values < 0.05). With the vision variables entered into the same model, baseline acuity and 2-year acuity loss were no longer statistically significant. Those with worse baseline scores in contrast sensitivity, central and lower peripheral visual fields were more likely to stop driving (trend p values < 0.05), and those who had 2-year losses in contrast sensitivity and lower peripheral visual fields were more likely to stop driving (trend p values < 0.05). Interactions with gender, other drivers in the house, or cognitive impairment were not detected. Conclusions. We present prospective data that indicate that older adults with worse scores in multiple measures of vision are more likely to stop driving and that contrast sensitivity and visual fields are most associated with driving cessation.