[A prevalence survey of blindness and visual impairment in adults aged equal or more than 60 years in Beixinjing blocks of Shanghai, China].

Objective: To investigate the prevalence rate of blindness and low vision and the leading cause of blindness in residents aged > or = 60 years in Beixinjing blocks, Shanghai.

Methods: A cross-sectional study was carried out by Shanghai First People's Hospital, affiliated Shanghai Jiaotong University and Shanghai Beixinjing Community hospital from November 2007 to April 2008. Randomly cluster sampling method was used, and all the individuals aged > or = 60 years in 8 communities from Beixinjing blocks, Shanghai was enrolled in this study. The pinhole visual acuity and presenting visual acuity 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 camara. Assigned ophthalmologic doctors assured the leading blind causes of every blind person. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out.

Results: 3851 individuals were examined, and the response rate was 92.73%. According to WHO diagnostic criteria: 29 persons were diagnosed as blindness, 11 male (37.93%) and 18 female (62.07%). 104 persons were diagnosed as low vision, 37 male (35.58%) and 67 female (64.42%). The prevalence rates of blindness and low vision were 0.75% and 2.70%. The leading causes of blindness were macular degeneration, cataract, corneal diseases, and retinal detachment. According to presenting vision diagnostic criteria: 61 persons were diagnosed as severe binocular blindness, 20 male (32.79%) and 41 female (67.21%). 66 persons were diagnosed as slight binocular blindness, 27 male (40.91%) and 39 female (59.09%). 276 persons were diagnosed as monocular blindness, 120 male (43.48%) and 156 female (56.52%). The prevalence of severe binocular blindness, slight binocular blindness and monocular blindness was 1.58%, 1.71% and 7.17%, respectively. The leading causes of blindness were macular degeneration, cataract, ametropia and corneal diseases.

Conclusion: The leading cause of blindness was macular degeneration. The prevalence of degenerative retinopathy in this area is on the rise.