Risk Factors for Motor Vehicle Collisions in Patients with Primary Open-Angle Glaucoma: A Multicenter Prospective Cohort Study

PURPOSE: To identify the incidence rate of motor vehicle collisions (MVCs) in patients with no ocular pathology other than primary open-angle glaucoma (POAG) and determine the putative risk factors for MVCs in this group of patients. METHODS: We designed a prospective cohort study across three centers utilizing a consecutive sampling method to identify all patients with POAG between the ages of 40 and 80 years old. Patients with glaucoma were consecutively screened for eligibility. All study participants answered a questionnaire about motor vehicle collisions at baseline, and answered the questionnaire again every 12 months (± 1 month) after baseline for three years. A binocular integrated visual field was calculated for each patient by merging a patient’s monocular Humphrey Field Analyzer (HFA) visual fields (VFs), using the ‘best sensitivity’ method. Patients with incident MVCs were defined as the “MVC+” group and patients without incident MVCs were defined as the “MVC-" group. Adjusted odds ratios for the incidence of MVCs were estimated with a logistic regression model. RESULTS: One hundred and ninety-one Japanese POAG patients were analyzed in this study. The age of the participants was 63.7 ± 10.2 [mean ± standard deviation]. A total of 28 participants experienced a MVC during the follow up period of three years (4.9% per year). Ten patients (5.2%) experienced a MVC in the first year, 13 patients (6.8%) in the second year, and 11 patients (5.8%) in the third year (some patients experienced multiple MVCs over different years). Best corrected visual acuity in the worst eye was significantly worse in the MVC+ group (0.03 ± 0.01, mean ± standard deviation, LogMar) compared with the MVC- group (0.01 ± 0.003, p = 0.01), and was the only variable identified as a significant predictor of future MVCs in the multiple logistic regression model [odds ratio: 1.2, 95% confidence interval (CI): 1.1 to 1.4]. CONCLUSION: Deterioration in visual acuity in the worst eye is a risk factor for future MVCs in patients with POAG.