Prevalence and causes of visual impairment and blindness in Sichuan province of China.

Abstract

To describe the prevalence and causes of low vision and blindness in a population within Sichuan province in southwestern China. A stratified, multi-phased and cluster probability sampling design was employed to enumerate 125641 participants from 40351 households within 38 counties/cities. Participants underwent a comprehensive eye examination, including standardized visual acuity (VA) tests using logarithm of the minimum angle resolution charts. Prevalence was age- and gender-standardized to the 2000 China Census. Population-weighted prevalence of blindness was 0.77% (95%CI: 0.72-0.82, n=966) and low vision was 1.22% (95%CI: 1.14-1.27, n=1513). Overall, the prevalence of visual disability was 1.40% in the urban population, and 2.22% in the rural population (P<0.01). Cataract was the leading cause of visual disability (55.7%, n=1381), and was of similar frequency in both urban and rural populations. Retinal disease was the second leading cause(9.7%, n=236), but was more common in urban than in rural participants (34.3% vs 2.7%, P<0.01). Corneal disease accounted for 6.5% (n=161) of cases of visual disability, and was more common in the rural population (7.2% vs 3.9%, P=0.006). We estimate that 1.72 million people suffer from visual disability within Sichuan province, of which 525000 are blind, the focus of blindness prevention should be in rural area.