Abstract
Purpose :
To investigate driving performance in patients with glaucomatous visual field loss in a driving simulator.
Methods :
The study included 103 glaucoma patients with repeatable bilateral visual field defects and 79 control subjects. All subjects underwent standard automated perimetry (SAP) and driving performance assessment on a simulator. Average SAP MD of the better and worse eyes of glaucoma patients were -4.60dB and -8.54dB, respectively. The driving simulation protocol consisted of a curve negotiation (CN) task, where the driver had to keep the car in the center lane on a winding road; and a car following (CF) task, where the driver had to follow a lead vehicle at a short distance in a straight road. Several metrics of performance were obtained, including curve and speed coherence, standard deviation of lane position (STLP), time to collision (TTC), STD of speed gain, STD of speed, and lane excursions. In addition, peripheral visual stimuli were presented simultaneously to driving tasks in order to investigate the ability to divide attention. Mean reaction times (RT) to peripheral stimuli were recorded. A global index of driving performance was calculated from principal component analysis of simulator data.
Results :
Glaucoma patients showed higher STD of speed (P=0.002) and decreased time to collision (P=0.039), suggesting a riskier behavior during car following task. Mean RT on divided attention tasks were also significantly higher in glaucoma than controls, suggesting impaired ability to divide attention. Mean RT during the curve negotiation task was 1.4±1.2 vs. 0.7±0.3s in glaucoma and controls, respectively (P<0.001). For the car following task, mean RT was 1.4±1.4 vs. 0.8±0.5s, respectively (P<0.001). On average, global driving performance was significantly worse in the glaucoma group compared to controls (0.59±2.96 vs. -0.77±1.47; P<0.001). Twenty-one patients with glaucoma (20.4%) showed impaired driving performance with global performance index above the 95th percentile cutoff calculated from the control group. Glaucoma patients with impaired driving ability showed significantly worse visual field results than those with above average performance (25.5 ± 5.2dB vs. 28.4 ± 3.0dB, P=0.004).
Conclusions :
A significant number of glaucoma patients show impaired driving performance as assessed by a driving simulator.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.