Vision standards for driving in Canada and the United States. A review for the Canadian Ophthalmological Society.

We review the vision requirements for driving with the goal of revising current Canadian Ophthalmological Society (COS) recommendations for vision standards for driving. The report comprises two sections. In the first section we report the results of a survey of transportation authorities in Canada and the United States conducted on behalf of the COS to determine the current standards and medical review procedures. The results suggest that although the standards in Canada are more consistent than those in the United States, few of the standards in either country are evidence-based. In the second section we review the recent literature on visual function and driving. We conclude from this review that adequate contrast sensitivity is as important as, if not more important than, good visual acuity for driving and that there is little evidence to support a monocular standard for acuity, contrast sensitivity or visual field. Although there is evidence that the extent of a visual field defect is related to the ability to perform driving tasks, there is little evidence to suggest a relation between the location of the visual field defect and fitness to drive.