Prevalence and causes of visual impairment in population more than 50 years old: The Shaanxi Eye Study

To assess the prevalence and causes of visual impairment (VI) in the elderly Chinese rural population in Shaanxi Province. A population-based, cross-sectional study design was used to determine the extent of VI in Chinese people over the age of 50 years in Shaanxi Province. Visual acuity and best-corrected visual acuity were measured using the logarithm of minimum angle of resolution chart. Blindness and low vision were defined according to WHO criteria. The major cause of VI was identified for all participants who were visually impaired. A total of 1912 residents completed a standard questionnaire and underwent a detailed eye examination, and the response rate was 90%. The overall prevalence of blindness and low vision were 1.5% and 8.2%. There was no statistically significant differences between genders in the prevalence of blindness and low vision (P > .05). The prevalence of blindness and low vision was higher among older individuals (P < .05) and lower (P < .05) among those with the highest education level. Cataract, corneal opacity, and glaucoma were considered as the main causes of blindness, which accounted for 67.9%, 10.7%, and 7.1%, respectively. Cataract, refractive error, and age-related macular degeneration were always considered as the leading causes of low vision, which accounted for 66%, 14.7%, and 5.8%, respectively. Cataract, corneal opacity, and glaucoma were the main causes of blindness and low vision in the population aged 50 years or more. The prevalence of these diseases that causes blindness and low vision was higher than that reported in other studies.