PURPOSE: To evaluate the association between the diagnosis of glaucoma and motor vehicle collision (MVC) involvement and driving avoidance in drivers aged > or =50 years. METHODS: Two groups of patients, one with glaucoma and one without, were identified in three university-affiliated eye care practices. Demographic, clinical, and driving characteristics were obtained by chart abstractions and a patient survey. Information regarding MVC involvement was obtained from police records. RESULTS: Patients with glaucoma were less likely (relative risk [RR], 0.67; 95% confidence interval [CI], 0.47-0.97) to be involved in collisions than patients without glaucoma. There was no difference between the at-fault crash rates of the patients with glaucoma and those without (RR, 1.22; 95% CI, 0.67-2.22). Patients with glaucoma had significantly higher levels of avoidance for driving at night (odds ratio [OR], 2.06; 95% CI, 1.11-3.82), driving in fog (OR, 3.80; 95% CI, 1.93-7.48), driving in the rain (OR, 2.99; 95% CI, 1.32-6.76), driving during rush hour (OR, 2.24; 95% CI, 1.16-4.34), driving on the highway (OR, 2.81; 95% CI, 1.19-6.64), and high density driving (OR, 2.88; 95% CI, 1.28-6.46). These associations were adjusted for demographic and medical characteristics as well as visual acuity. CONCLUSIONS: Older persons with glaucoma drive at least as safely as, if not more safely than, older persons without glaucoma.