Prevalence of blindness and causes of visual impairment among adults aged 50 years or above in southern Jiangsu Province of China

Objective: The prevalence of blindness and low vision among adults aged = 50 years in southern Jiangsu Province were surveyed and estimated. Methods: Cluster sampling was employed from January to September 2010 to randomly select 6,722 individuals aged = 50 years in 28 clusters from southern Jiangsu Province. The survey was preceded by a pilot study, which refined operational methods and conducted quality assurance evaluation. Eligible individuals were registered for visual acuity measurement and eye examination. Results: A total of 6,155 individuals were recruited, and a response rate of 91.50% was obtained. The prevalence of bilateral blindness and low vision were found to be 0.76% and 1.37%, respectively. Subjects with monocular blindness and low vision were 3.27% and 3.48%, respectively. Among the individuals evaluated, 201 were detected to have monocular blindness and 47 with bilateral blindness. In addition, 55 of the 201 subjects with monocular blindness were found to suffer from low vision of the other eye. Among the 295 subjects with blind eyes, 116 (39.32%), 31 (10.51%), and 28 (9.49%) were caused by cataract, high myopia macular degeneration, and atrophic eyeballs, respectively. In the 437 subjects with low-vision eyes, 223 (51.03%), 41 (9.38%), and 41 (9.38%) had cataract, high myopia macular degeneration, and age-related macular degeneration, respectively. Conclusions: Blindness and low vision are caused by descending cataract, age-related macular degeneration, high myopia macular degeneration, and atrophic eyeballs.