2010 BC Guide in Determining Fitness to Drive

Retinitis pigmentosaRetinitis pigmentosa is the term given to a group of hereditary retinal diseases that result in thedegeneration of rod and cone photoreceptors. The diseases cause progressive visual loss, endingin blindness. Night blindness is an early symptom of retinitis pigmentosa, followed by aconstriction of the peripheral visual field. Loss of central vision typically occurs late in thecourse of the illness.Typically, symptoms are not prominent in childhood, but with progressive degeneration of thephotoreceptor cells, vision is gradually lost during adolescence and adulthood.Medical treatments causing vision impairmentLaser surgery – LASIK and PRPLaser surgery may also cause vision impairments. Laser assisted in situ keratomileusis (LASIK)is a type of refractive laser eye surgery performed by ophthalmologists. It is increasingly beingused to correct myopia, hyperopia, and astigmatism. Panretinal laser photocoagulation (PRP) isthe current treatment of choice for diabetic retinopathy.Possible complications of laser procedures include over or under correction, regression (return tothe original refractive state), halos and glare, double vision (ghosting), loss of contrastsensitivity, and loss of visual acuity.21.2 Prevalence and incidence of vision impairmentsBlindness/low visionBased on WHO classifications, the prevalence of low vision and blindness in Canada is 35.6 and3.8 per 10,000 individuals, respectively. Among individuals with some vision loss (vision worsethan 20/40), cataract and visual pathway disease were the most common causes, togetheraccounting for 40% of visual impairment. Age-related macular degeneration and other retinaldiseases were the next most common causes of vision loss, with diabetic retinopathy andglaucoma less frequently encountered as causes of visual impairment.Myopia, hyperopia, astigmatism, and presbyopia (refractive errors)The prevalence of visual conditions such as astigmatism, hyperopia, myopia, and presbyopia inCanada is difficult to determine due to the absence of population based studies evaluating theocular health of Canadians.Night myopia is relatively common among younger individuals, with an estimated prevalence of38% in those 16 to 25 years of age.259