2010 BC Guide in Determining Fitness to Drive

Monocular vision, impaired contrast sensitivity, impaired dark adaptation andglare recoveryThere are no data on the prevalence of monocular vision, impaired contrast sensitivity, orimpaired dark adaptation and glare.Visual field loss including hemianopiaResearch indicates that the prevalence of visual field loss for those age 16 to 60 years is between3 and 3.5%, rising to 13% for those 65 and older.DiplopiaThere are no data on the prevalence of diplopia.NystagmusAlthough the prevalence of nystagmus is not accurately known, the condition is believed toaffect around 1 in 5,000 individuals.21.3 Prevalence and incidence of medical conditions causing visionimpairmentsCataractsCanadian data on the prevalence of cataracts are lacking, but statistics from the United Statesindicate that approximately 17% of Americans 40 years old and older have a cataract on at leastone eye. Cataracts frequently occur bilaterally (in both eyes), with the prevalence of bilateralcataracts greater among women than men. Overall prevalence of cataracts increases with age,leading to increasing prevalence in the future as the population ages. United States censusestimates project that the prevalence of cataracts will increase by 50% by the year 2020.Cataracts are more common in women and affect Caucasians somewhat more frequently thanother races, particularly with advancing age. Risk factors for age-related cataracts includediabetes, prolonged exposure to sunlight, use of tobacco, and use of alcohol.Diabetic retinopathyIndividuals with both Type 1 and Type 2 diabetes are at-risk for diabetic retinopathy. At presentthere is little published information about the prevalence of diabetic retinopathy in Canada. Astudy from the United States indicates that, after 20 years from the onset of diabetes, over 90%of people with Type 1 diabetes and more than 60% of people with Type 2 diabetes will havediabetic retinopathy.260