Rapid assessment of avoidable blindness in Kunming, china.

OBJECTIVE: To estimate the magnitude and causes of visual impairment (VI) in people aged > or = 50 years in Kunming using the Rapid Assessment for Avoidable Blindness methodology, and to assess the prevalence of a pupillary defect in participants diagnosed as cataract visually impaired. DESIGN: Population-based cross-sectional survey. PARTICIPANTS: We enrolled 2760 residents of Kunming prefecture in southwest China, >50 years of age. METHODS: Forty-six clusters of 60 people were selected based on population proportional to size. Households from each cluster were selected using compact segment sampling (CSS) or quota sampling when CSS was not feasible. Visual acuity (VA) was assessed using a tumbling E chart. Lens status and cause of VI were determined by ophthalmologists using direct ophthalmoscopy through a dilated pupil where necessary. The pupillary reaction was assessed on undilated pupils when VI was detected. MAIN OUTCOME MEASURES: Prevalence of blindness (VA6/18). The main barrier to cataract surgery was cost. CONCLUSIONS: Cataract remains the most important cause of preventable blindness in this poor region of China, and affordable provision of surgery would help to address this problem. Some cases of cataract blindness may not be preventable owing to preexisting comorbidity, as detected by the presence of a pupillary defect