Driving performance in patients with mild to moderate glaucomatous clinical vision changes

The purpose of this study was to determine the relationship between clinical measures of visual function and driving-related skills in patients with glaucoma who had good visual acuity in at least one eye and mild to moderate visual field loss. Methods. Twenty-five patients with glaucoma and twenty-nine age-equivalent normally sighted control subjects were included in the study. We tested each patient on an interactive driving simulator and collected vision data, including Lighthouse visual acuity, Goldmann and Humphrey visual fields, and Pelli-Robson contrast sensitivity. Information about real-world accident history for the previous 5-year period was obtained. Results. The glaucoma patients did not have significantly more simulator or real-world accidents than the normally sighted group. There were no significant differences between the groups in performance on seven of the eight simulator indexes that were measured. Of the clinical visual function measures, only lower contrast sensitivity in the eye with better contrast sensitivity correlated with driving skills, including slower speeds (r(24) = 0.58, p ≤ 0.01), more lane boundary crossings (r(24) = -0.54, p ≤ 0.01), and longer braking response times (r(24) = -0.60, p ≤ 0.01) for the patient group. Conclusion. Reduced contrast sensitivity may be important in indicating the level of driving skills for individuals with glaucoma, who have normal or near-normal visual acuity and mild to moderate visual field loss.