1 Laboratory of Experimental Ophthalmology,
² Department of Neuropsychology,
University of Groningen, P.O. Box 30.001, 9700 RB Groningen, 
The Netherlands.

Some subjects with visual field defects are still able to drive safely. It has been suggested that these drivers have spontaneously developed compensatory viewing strategies. However, not all subjects with visual field defects develop compensatory viewing strategies successfully. This research project addresses three main questions: What is the relationship between visual functions and driving behaviour in subjects with visual field defects? Can compensatory viewing strategies be trained? And, will compensatory viewing strategies enhance driving safety?

Subjects with central or peripheral field defects are assessed with regard to elementary visual functions, viewing behaviour, visual attention, and driving. Subsequently, subjects who failed the driving test, are allocated to one of three training programs. All training programs are developed to teach compensatory viewing strategies but their methods differ. The function training makes use of tasks on a computer screen to teach and train compensatory viewing strategies. The mobility training teaches compensatory viewing strategies while walking or cycling in a real traffic situation. The strategy training teaches compensatory behaviour while driving a car. Viewing strategies and driving behaviour are assessed immediately after training and once again three months later.

Results

Preliminary results show that 1) one third up to one half of the subjects who do not meet the vision requirements for driving proved to be safe drivers and are thus incorrectly restricted from driving, 2) subjects scanned approximately 27 per cent faster after training than they did before training. This was particularly so for subjects in the function and mobility training, 3) viewing behaviour while driving improved for subjects in the strategy training. Preliminary results thus show that 1) contemporary driving requirements are too strict, 2) viewing strategies can be trained successfully and 3) training seems to be task specific.

Support: Dutch Research Council (NWO), Visio: The Dutch National Foundation for the Visually Impaired and blind.