Eyes, brains, and autos

Vision disorders pose a driving safety risk and commonly arise at the level of the eye in cataract, glaucoma, macular degeneration, and diabetic retinopathy and at the level of the brain in advancing age, stroke, and Alzheimer disease and related conditions. These disorders can increase driver safety errors because of reduced visual acuity, contrast sensitivity, and visual fields. Aging and brain lesions, especially, can also reduce the useful field of view in drivers with normal visual fields; increase the attentional blink and change blindness; impair perception of structure and depth from visual motion cues and motion parallax; decrease perception of heading from optical flow and detection of impending collisions; and increase the chance of getting lost. Better tools are needed for detecting and alerting visually impaired drivers who are at greatest risk for a crash. These drivers can be assessed with a state-administered road test, instrumented vehicles, and driving simulators. Emerging safety interventions include optical and electronic visual aids for visually impaired drivers, coupled with new vehicle designs, onboard warning devices, and reflective clothing that highlights the motion of pedestrians.