A prevalence investigation of blindness and vision impairment in 2009 in older adults of Dachang Blocks of Baoshan District, Shanghai, China

Abstract

To investigate the prevalence of blindness and low vision and the leading causes of blindness in residents aged≥60 years in Dachang Blocks of Baoshan District, Shanghai, China. A cross-sectional study was carried out by Shanghai Eye Disease Prevention & Treatment Center and the Center for Disease Control and Prevention in Baoshan District of Shanghai from October to December in 2009. Randomly cluster sampling was used to identify the adults aged≥60 years who had lived in Dachang Blocks of Baoshan District, Shanghai for more than 10 years. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) based on autorefraction and subjective refraction were measured separately in each eye. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using slit lamp-microscopes direct ophthalmoscopy and non-mydriatic digital camera. And the leading causes of visual impairment were assured. The Chi square test was used between the groups of rate comparison. Of 5199 enumerated subjects≥60 years of age, 87.42% (4545/5199) were examined. All subjects were urban population who were originally changed from the rural population in nearly 10 years. In this population, with best-corrected visual acuity, 30 persons were diagnosed as blindness, 145 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.67%, 3.19%, respectively. Low vision was associated with female gender. It was statistically significant difference (χ2=4.88, P<0.05). The leading causes of blindness were cataract, macular degeneration, ocular absence or atrophy, glaucoma, and diabetic retinopathy or corneal diseases. With presenting visual acuity, 39 persons were diagnosed as blindness, 401 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.86%, 8.82%, respectively. Blindness and low vision were associated with older age. The prevalence of blindness and low vision increased rapidly in aged 75 years or older people. The leading causes of blindness were cataract, uncorrected refractive error, macular degeneration, ocular absence or atrophy, glaucoma. Low vision was associated with female gender. It had statistically significant difference (χ2=13.345, P<0.01). In rapidly urbanized and aging community of Shanghai, cataract, uncorrected refractive error, macular degeneration were the leading causes of blindness with presenting visual acuity. The prevalence of low vision in females was higher than that of males which had statistically significant difference. These kinds of residents needed more targeted eye health education and services.