to assessthe Prevalence and related risk factorsof PrimaryoPen angle glaucoma (POAG) in a rural PoPulation in Shaanxi Province. ·METHODS: By using a stratified, cluster-based, random samPlingtechnique, 8 500 Personsof all ages were selected randomly, fromthe North,the South andthe Middleof Shaanxi Province from Julyto December in 2006. All ParticiPants had an interview with a standard questionnaire andthose questions relatedto glaucomaof Previous diagnosis andtreatment, family history andoutbreak history.then a detailed and relative eye examination was Performed, including logarithmofthe minimum angleof resolution visual acuity, external eye examination with slit-lamP biomicroscoPy and fundus examination.the intraocular Pressure(IOP) was measured with Perkins aPPlanationtonometrytothose Persons aged 50 yearsoldor more andthose with susPected increased IOP. A further examination was Performedtothose Persons with susPicious glaucoma, including rePeatedtonometric examination, gonioscoPy, dark roomtest, automated visual fieldtesting, et al . ·RESULTS: Atotalof 6 815 amongthe eligible 8 500 Personsof all ages were interviewed and examined from Julyto December in 2006, a resPonse rateof 80.18%. Nine ParticiPants were foundto have POAG, withthe Prevalenceof 0.13%, age ranging from 38to 80 years (mean year: 62.0). Inthose aged 30 yearsoldor more,the Prevalenceofthe disease was 0.23%, 0.28% and 0.39% forthose morethan 40 and 50 yearsold, resPectively.the rateof susPicious POAG was 0.18% (12 cases) with age ranging from 35to 77 years (mean year: 54.7). With multiPle logistic analyses,the Prevalence increased significantly with age (P =0.023).Otherthan increasing age, myoPia was also a strong risk factor for POAG.of 9 ParticiPants with POAG,only 2 cases (22.22%) had been Previously diagnosed. Noone with POAG was received anytreatment Previously. 66.67%(6 cases) ParticiPants with POAG suffered from visual imPairment in various degrees secondaryto POAG.the Percentageof blindness in either eye was 33.33%. ·CONCLUSION:the Prevalenceof POAG is closetothat fromother Chinese PoPulations, increasing with age. A majorityof glaucoma was undiagnosed and untreated Previously.