The Prevalence And Causes Of Visual Impairment In An Elderly Chinese Tujia Ethnic Rural Population:the Chongqing Minority Eye Study

Purpose To investigate the prevalence and causes of visual impairment in an elderly Tujia Ethnic rural population in south-wast China.Method A Random cluster sampling study was conducted in 50 years and older of Tujia ethnic group living in the Qianjiang and Youyang of Chongqing.Blindness and low vision were defined according to World Health Organization criteria.The prevalence of visual impairment(VI)was estimated,and causes were identified based on best-corrected visual acuity(BCVA)as well as presenting visual acuity(PVA).Results We conducted ocular examinations in 2122 participants(83.02%participation rate).Using the WHO criteria,the prevalence of visual impairment,low vision and blindness based on PVA was 11.2%(BCVA,6.2%)and 4.0%(BCVA,1.8%).According to the United States criteria,the prevalence of low vision and blindness was 25.5%(BCVA,10.0%)and 4.9%(BCVA,2.5%),respectively.Low vision and blindness were significantly associated with age(P < 0.05)and level of educational background(P<0.001),It was not associated with gender(P>0.05).Taking the BCVA,cataract(79.3%)was the most common cause for visual impairment followed by age-related macular degeneration(10.7%),corneal opacity(4.1%),posterior capsular opacification(3.6%).The majority of PVA-defined visual impairment cases were attributable to cataract(50.0%)and uncorrected refractive error(35.7%).Conclusion The prevalence of VI in elderly Tujia Ethnic rural population is higher than that in development countries or arears and Hans。The main cause of VI is treatable,for example cataracts and uncorrected refractive error,is high among the elderly Tujia nationality.They would,therefore,benefit from a more aggressive and depth eyecare program as a blindness-prevention strategy to an increasing number of elderly people and those with little or no education.