Driving with Hemianopia: 1. Detection Performance in a Driving Simulator
Alexandra R Bowers 1*,
Aaron J Mandel 2,
Robert B Goldstein 1,
and
Eliezer Peli 2
1 Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts, United States
2 Harvard Medical School, Schepens Eye Research Insitute, Boston, Massachusetts, United States
* To whom correspondence should be addressed. E-mail: alex.bowers{at}schepens.harvard.edu.
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Abstract |
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Purpose: This study was designed to examine the effect of homonymous hemianopia (HH) on detection of pedestrian figures in multiple, realistic and hazardous situations within the controlled environment of a driving simulator.
Methods: Twelve people with complete HH, and without visual neglect or cognitive decline, and twelve matched normally-sighted (NV) drivers participated. They drove predetermined city and rural highway routes (total 120 minutes) during which pedestrian figures appeared at random intervals along the roadway (R-Peds; n = 144) and at intersections (I-Peds; n = 10). Detection rates and response times were derived from participant horn-presses.
Results HH drivers exhibited significantly (p < 0.001) lower R-Ped detection rates on their blind side than NV drivers (range 6% to 100%). Detection of I-Peds on the blind side was also poor (8% to 55%). Age and blind-side detection rates were negatively correlated (Spearman r = 0.71, p = 0.009). Although blind-side response times of HH drivers were significantly (p < 0.001) longer than NV drivers, most were within a commonly-used 2.5s guideline.
Conclusions: Most HH participants had blind-side detection rates that seem incompatible with safe driving; however, the relationship of our simulator detection performance measures to on-road performance has yet to be established. In determining fitness to drive for people with HH, our results underscore the importance of individualized assessments including evaluations of blind-side hazard detection.
Key Words:
low vision, hemianopia, driving, detection rates
