Causes of Visual Impairment and Blindness in the 2006 and 2014 Nine-Province Surveys in Rural China

Purpose To investigate the primary causes of visual impairment and blindness in rural China. Design Population-based, cross-sectional study. Methods Geographic cluster sampling was used in randomly selecting residents from a rural county/district within 9 provinces in the East Coast, Inland Middle, and West regions of mainland China. Persons aged 50 years or older were enumerated through household visits and invited to examination sites for visual acuity testing and ocular examination. Causes of vision impairment and blindness in 2014 were compared with data from an earlier 2006 survey. Results Mild visual impairment (20.4% prevalence) was caused by uncorrected refractive error in two thirds of cases and by cataract in nearly another one fourth; moderate-to-severe visual impairment (10.3% prevalence) was caused by cataract in over onec half of cases and by uncorrected refractive error in another one fifth; blindness (1.66% prevalence) was caused by cataract in approximately one half of cases and in another one fourth by retinal disease. Primary causes of visual impairment and blindness in cataract-operated eyes were uncorrected refractive error, posterior capsule opacity, and retinal disease. From 2006 to 2014, the proportion of visual impairment caused by uncorrected refractive error increased, but rates for unoperated cataract were reduced. Conclusions Uncorrected refractive error and unoperated cataract are the 2 primary causes of mild, moderate, and severe visual impairment in rural China, with unoperated cataract and retinal diseases primary causes for blindness. An effective public health strategy to increase service delivery for these causes would lead to substantial reduction in vision impairment and blindness.