Driving behaviour and visual compensation in glaucoma patients: Evaluation on a driving simulator.

BACKGROUND

To assess the driving performance and both the visual scanning and driving compensations of glaucoma patients.

METHODS

In this case-control pilot study, the driving behaviour and performance of 14 patients with glaucoma and nine healthy age- and sex-similar control subjects were compared in a fixed-base driving simulator. All subjects performed in four scenarios with one to two hazardous situations on urban streets, for a total of five hazards. Measurements taken during the tests included reaction times, longitudinal regulation, lateral control and eye and head movements.

RESULTS

Glaucoma patients showed poor driving performance with longer reaction time to hazardous situations than control subjects: pedestrians crossing the road from the left (p < 0.022) or from the right (p = 0.013), and vehicles coming from the left (p = 0.002). Their mean duration of lateral excursion was longer (p = 0.045), and they showed more lane excursions in a wide left curve (p = 0.045). Glaucoma patients also showed a higher standard deviation of time-headway (p = 0.048) with preceding vehicles. Analyses of driving behavioural compensations on curved roads showed that glaucoma patients stayed closer to the centre line in large (p = 0.006) and small (p = 0.025) left curves and on small right curves (p = 0.041). Additionally, on straight roads, as compared to control subjects, glaucoma patients showed longer mean time-headway (p = 0.032) and lower mean speed (p = 0.04). Finally, the glaucoma group exhibited a larger standard deviation of horizontal gaze (p = 0.034) than the control subjects.

CONCLUSIONS

In a virtual driving environment, glaucoma patients exhibited unsafe driving behaviours, despite their driving and eye-scanning compensations.