Driving with Hemianopia, II: Lane Position and Steering in a Driving Simulator

PURPOSE. The hypothesis that drivers with homonymous hemianopia (HH) would take a lane position that increased the safety margin on their blind side was tested with a driving simulator. METHODS. Twelve participants with HH (six right HH and six left; nine men; mean age, 50 years; range 31-72), and 12 matched current drivers with normal vision (NV) each completed approximately 120 minutes of simulator driving. Lane position and steering stability were evaluated for specific road segment types (straight segments, curves, and turns) in city and rural undivided highway driving. RESULTS. The drivers with right HH held a lane position significantly (P = 0.001) to the left of NV drivers on the straight road segments and to a lesser extent on the curves. The drivers with left HH had a lane position similar to that of the NV drivers on straights and curves, but followed a significantly (P = 0.005) more rightward path on the left turns. CONCLUSIONS. The results support the hypothesis that drivers with HH take a lane position that increases the safety margin on their blind side; however, absolute lane position varies as the steering maneuver and location of the risk from oncoming traffic change with road segment type. (Invest Ophthalmol Vis Sci. 2010; 51: 6605-6613) DOI:10.1167/iovs.10-5310