Driver Fitness in Patients with Cognitive Impairment and Glaucoma

Recent evidence suggests a relationship between cognitive impairment and glaucoma. Whether impaired visual perception in glaucoma contributes to reduced cognitive function in patients with dementia, or cognitive impairment further limits visual perception due to optic nerve damage in glaucoma is unclear. One objective of this study was to see if there were significant differences on measures of perceptual, cognitive and driving performance between older drivers with cognitive impairment and/or glaucoma who still had good visual acuity. A second goal was to measure the strength of association between measures of visual, cognitive, and driving performance. 302 older drivers were classified as having glaucoma alone (n=69), cognitive impairment alone (n=41), both (n=21) or neither (n=171). All participants had good visual acuity, a valid drivers license and were still driving. Demographic, health status, driving accidents and clinical tests of vision and driving performance variables were analyzed using one-way ANOVAS and Pearson correlations. Across demographic, clinical and driving measures there were significant differences between those with cognitive impairment, with or without glaucoma, and controls. Subjects with glaucoma showed significant differences with controls on accidents, driving simulation tests of divided attention and car following delay. Driving simulator and UFOV measures were significantly correlated with self reported accidents. Driving simulation is a valid way to evaluate task performance and may be a more sensitive and salient method of detecting the additive and/or interactive effects of glaucoma and cognitive impairment in older drivers than vision and neuropsychological tests alone.