Vision impairment, eye disease, and injurious motor vehicle crashes in the elderly

The objective of this case-control study was to identify visual risk factors for vehicle crashes by elderly drivers which result in injury. The sample consisted of licensed current drivers between 55 and 87 years of age who resided in Jefferson County, Alabama. Subjects were identified through Alabama Department of Public Safety (ADPS) files. Two groups of cases were identified. One group (N = 78) was defined as those drivers who had incurred at least one vehicle crash between 1985 and 1990 resulting in an injury to anyone in the involved vehicles according to the accident report. The other case group (N = 101) consisted of drivers involved in non-injurious crashes during the same time period. Controls (N = 115), also selected from ADPS files, were older drivers not involved in crashes during the same five-year period. Subjects underwent a battery of visual processing tests and a comprehensive eye examination. The main results were that restricted useful field of view and glaucoma were the only significant independent predictors of injurious crash involvement. Odds ratios (ORs) for reductions in the useful field of view of 23-40%, 41-60% and greater than 60% were 4.2 (95% confidence interval [CI], 1.5-11.8), 13.6 (95% CI, 5.8-39.7), and 17.2 (95% CI, 5.3-55.6), respectively, compared to reductions of less than 23% (p for trend < 0.001). The OR for glaucoma was 3.6 (95% CI, 1.0-12.6). Useful field of view impairment was the only variable independently associated with non-injurious crash involvement. This study implies that impaired visual processing and glaucoma may play a role in the etiology of older driver crashes which result in injury.