Binocular Visual Field Loss and Crash Risk: An eFOVID Population-Based Study.

Purpose: Visual field loss poses a high personal cost to those affected, significantly impacting activities of daily living, including driving. However, there is conflicting evidence on the association between visual field loss and crash risk. This study examined the association between severity and location of binocular visual field loss and motor vehicle crashes in older adults aged 50+, using linked population data over a 29-year study period.

Methods: Using a database of visual field tests obtained from ophthalmologists in Western Australia (WA) between 1990 and 2019, deficits in field sensitivity were identified and classified into three severities across five regions. This was linked to other government administrative databases including crash data.

Results: Of 31,296 people, 4,307 (13.76%) older drivers were involved in 5,537 vehicle crashes. Binocular visual field loss (regardless of severity and location) significantly increased the odds of a crash by 84% (OR 1.84; 95% CI 1.71-1.97). Severe visual field loss significantly increased the odds of a crash by 98% in the upper left quadrant (OR 1.98; 95% CI 1.70-2.06), 97% in the lower left (OR 1.97; CI 1.80-2.16), 89% in the lower right (OR 1.89; CI 1.72-2.06) and 95% in the upper right quadrant (OR 1.95; CI 1.78-2.14).

Conclusion: The large population-based study provided robust estimates on the degree of severity and specific locations of visual field loss that threaten safe driving and objective evidence on the usefulness of linking large customised ophthalmic databases to crash records for developing 'fitness to drive' guidelines for older drivers.