Training compensatory viewing strategies:feasiblity and effect on practical fitness to drive in subjects with visual field defects

Fifty-one subjects with visual field defects were trained to use compensatory viewing strategies.The subjects were referred to the training program by an official driving examiner of the Dutch Central Bureau of Driving Licenses. Three training programs were compared: laboratory training, mobility training, and motor traffic training. Viewing behavior, visual attention, and practical fitness to drive were assessed before and after training. Practical fitness to drive was assessed on the road as well as in a driving simulator. It was observed that compensatory viewing behavior and practical fitness to drive could be improved by training. Subjects in the motor traffic training showed a small advantage with regard to practical fitness to drive, suggesting that training is task-specific and that generalization is limited. The effect of visual field defect on viewing behavior and practical fitness to drive was analyzed separately for subjects with central or peripheral visual field defects. It was observed that none of the outcome measures differed between the central and peripheral visual field defect groups

Compensatory viewing training improves practical fitness to drive of subjects with impaired vision

In many countries strict legal requirements for obtaining a driver’s license are in effect for visual acuity and visual field.We studied the relationship between these characteristics and driving safety and driving proficiency in an on-the-road test of practical fitness to drive in subjects with visual disorders, including many subjects scoring below current criteria. We further studied how far the relationship between the on-the-road test and visual measures improved if compensatory eye movements and visual attention were included in the criteria. Lastly, we studied the effects of training compensatory viewing strategiesformed the on-the-road test before and after training. Training consisted of laboratory and mobility training, including driving instruction. Visual function assessment included acuity, visual field, contrast sensitivity, visual attention, compensatory viewing efficiency, and visuospatial tests. In one study an advanced driving simulator was used besides the on-the-road assessment. Two models were compared to predict the on-the-road score. Results: 13–62% of the subjects passed the on-the-road test before training. After training, an additional 15–45% passed. The power of both models to predict the on-the-road score rose to about 45% by adding viewing behavior in the driving simulator. Discussion: A considerable percentage of the subjects, legally not allowed to drive, passed the on-the-road test. Sensitivity and specificity of vision tests and driving simulator tests are still too low to decide upon unfitness to drive. Training of compensatory viewing improved the performance in the on-the-road test