Population-based survey of prevalence, causes, and risk factors for blindness and visual impairment in an aging Chinese metropolitan population

Int J Ophthalmol. 2017 Jan 18;10(1):140-147. doi: 10.18240/ijo.2017.01.23. eCollection 2017.

Abstract

Aim: To assess the prevalence, causes, and risk factors for blindness and visual impairment among elderly (≥60 years of age) Chinese people in a metropolitan area of Shanghai, China.

Methods: Random cluster sampling was conducted to identify participants among residents ≥60 years of age living in the Xietu Block, Xuhui District, Shanghai, China. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were checked by the Early Treatment Diabetic Retinopathy Study (ETDRS) visual chart. All eligible participants underwent a comprehensive eye examination. Blindness and visual impairment were defined according to World Health Organization (WHO) criteria.

Results: A total of 4190 persons (1688 men and 2502 women) participated in the study, and the response rate was 91.1%. Based on PVA, the prevalence of blindness was 1.1% and that of visual impairment was 7.6%. Based on BCVA, the prevalence of blindness and visual impairment decreased to 0.9% and 3.9%, respectively. Older (≥80 years of age) women, with low educational levels and smoking habits, exhibited a significantly greater chance for blindness and visual impairment than did those with high educational levels and no smoking habits (P<0.05). Based on PVA and BCVA, the main causes of blindness were cataract, myopic maculopathy, and age-related macular degeneration (AMD).

Conclusion: Our findings help to identify the population in need of intervention, to highlight the need for additional eye healthcare services in urban China.

Keywords: blindness; cross-sectional study; prevalence; risk factor; visual impairment.