Abstract
Purpose :
Canada does not have published data on the incidence of visual impairment. Our goal was to determine the 3-year incidence of visual impairment (VI) in Canada and its risk factors.
Methods :
Data from 23,973 adults taking part in the Canadian Longitudinal Study on Aging Comprehensive Cohort baseline and 3-year follow-up exams were included in this prospective 3-year cohort study. Inclusion criteria included being 45 to 85 years of age, community-dwelling, and living near one of the 11 data collection sites across 7 Canadian provinces. Presenting binocular visual acuity was measured using the Early Treatment of Diabetic Retinopathy Study chart. VI incidence was defined as the development at follow-up of visual acuity worse than 20/40 in those with acuity better than or equal to 20/40 at baseline. Logistic regression was used to account for the complex survey design.
Results :
3.99% (95% Confidence Interval (CI) 3.75, 4.25) of Canadian adults developed VI over a 3-year period. There was a high degree of variability in the incidence rates between Canadian provinces with a low of 1.42% in Manitoba and a high of 7.33% in Nova Scotia. Uncorrected refractive error was the leading cause. Risk factors for incident VI included older age (odds ratio (OR)=1.07, 95% CI 1.06, 1.07), Black race (OR=2.64, 95% CI 1.36, 5.14), lower household income (OR=1.73 for those making less than $20,000 per year, 95% CI 1.24, 2.40), current smoking (OR=1.78, 95% CI 1.37, 2.32), and province.
Conclusions :
Incidence of visual impairment is common in older Canadian adults, varies markedly between provinces, and is largely due to treatable causes. Risk factors for VI suggest sub-groups that may benefit from interventions to improve access to eye care.
This is a 2021 ARVO Annual Meeting abstract.