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Abstract
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OBJECTIVE: The visual field is considered to play an outstanding role regarding fitness to drive. Aim of this study was to assess the impact of homonymous visual field defects (HVFDs) on the passage of an intersection with cross road traffic under additional consideration of the visual exploration (use of eye and head movements).
METHODS: HVFDs (assessed by binocular SKP within the 90A° visual field, stimulus III4e) as well as exploratory movements (assessed with eye and head tracking) were superimposed on the trajectories of the virtual vehicles on a temporal or spatial scale. The following parameters were visualized and analyzed: (i) if at all, and when yes, (ii) in which time-point/in which distance from the intersection, (iii) for how long regarding distance and time, a potentially collision-relevant vehicle was explored, and (iv) if exploration of collision-relevant vehicles resulted in a modification of driving behavior (in terms of speed).
RESULTS: 27 patients (10 female, 17 male, age range: 19-71 years) with HVFDs due to vascular brain lesions (time span after brain lesion al least 6 months) were examined. The control group included 16 normal-sighted subjects with similar age and gender distribution. 17 out of 27 patients were comparable to the normal-sighted collective regarding performance (number of accidents) in the passage of the intersection. Patients with left-sided HVFDs due to right-sided brain lesions had a worse driving performance in comparison to patients with right-sided HVFDs.
CONCLUSIONS: Location and extent of HVFDs per se seem to be inadequate in predicting the successful passage of an intersection under virtual reality conditions. |