To assess the prevalence and causes of visual impairment and blindness in adults living in an urban area of southern China.
Random cluster sampling was used to identify the adults 50 years and older living in the Liwan district of Guangzhou, China. Presenting visual acuity (PVA) with habitual correction and best-corrected visual acuity (BCVA) based on autorefraction and subjective refraction were measured using the Early Treatment Diabetic Retinopathy Study visual chart. Blindness and low vision were defined according to World Health Organization criteria. Eyes with visual impairment were assigned 1 principal cause for the impairment.
Visual acuity measurements were available for 1399 adults 50 years and older (75.3% participation rate). The prevalence of blindness and low vision based on the PVA was 0.6% (95% confidence interval, 0.2%-1.0%) and 10.1% (95% confidence interval, 8.5%-11.7%), respectively. These rates were reduced to 0.5% and 3.1% when the BCVA was considered. Based on the PVA, the principal causes for blindness were cataract (39.6%), glaucoma (11.0%), and myopic maculopathy (6.6%). The majority of low vision cases were attributable to cataract (45.3%) and uncorrected refractive error (43.9%).
The majority of eye diseases leading to visual impairment are potentially treatable in this population.