Rapid Assessment Of Avoidable Blindness Survey And The Survey Research In Mianning

Objective:To estimate the prevalence of visual impairment(VI),the cause of Eyesight disabled and the situation of Cataract operations in people aged =50 years in Mianning using the Rapid Assessment for Avoidable Blindness methodology,and to explore the reason of influencing cataract surgery's coverage and the low vision after the operation in this prefecture.In comparison with the data of the second national sample survey for disabled persons of Sichuan in 2006,to evaluate the advantages and disadvantages of two kinds of survey.Methods:1.We enrolled 2850 residents of Mianning prefecture in sichuan province,who ? 50 years of age were make an investigation of the Rapid Assessment for Avoidable Blindness from June to August,2006.57 clusters of 50 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 simple vision chart.Lens status and cause of VI were determined using direct ophthalmoscopy and Portable slit lamp.2.Reorganizing the data of the second national sample survey for disabled persons of sichuan province in 2006 so that it can be compared with the data of VI in people aged ?50 years in Mianning.Results:1.Of 2850 enumerated residents,2817 were examined(98.8%).Referred to the visual impairment standard of WHO,537 were visual disabled.The prevalence of VI was 19.1%.111 of them were bilateral blindness.The prevalence of blindness was 3.9%(95%confidence interval[CI],3.2-4.7%).69 of them were severe visual impairment.The prevalence of SVI was 2.4%(95%CI,1.8-3.1%).3 57 of them were visual impairment The prevalence of VI was 12.7%(95%CI,10.5-14.9%).87.4%of them were avoidable blindness.The main cause of blindness were untreated cataract(55.9%of blindness),posterior segment disease(14.7%),corneal lesion(6.3%).The cataract surgical coverage was only 57.1%,and 58.5%of operated eyes had good outcome with available correction(VA>0.3).The main barrier to cataract surgery was that the patients didn't know the cataract can be treated.2.This investigation found that 2479 of 125641 clients were visual disabled.71.1%of visual disabled(1778)was people aged ?50 years old:679 of them were blind.The prevalence of blindness was 1.64%.279 of them were SVI.The prevalence of SVI was 0.67%.820 were VI.The prevalence of VI was 1.99%.The main cause of blindness was cataract,followed by posterior segment disease,and corneal lesion.Conclusions:1.The prevalence of blindness in people aged = 50 in Mianning was 3.9%,87.4%of them were avoidable blindness.The main cause of blindness was still untreated cataract.2.People in Mianning faced the huge challenges of blindness owing to the low coverage and large amount of patients need cataract surgery.It needed to press on with efforts in Publicity and education and hardware facilities.3.The RAAB is quick,simple,accurate as an investigation methodology of rapid assessment of avoidable blindness.