Variations In Ocular Dimensions And Prevalenc Of Glaucoma In A Rural Population Of Ethnic Bai,Yi And Han In The Yunnan Province Of China

Part 1:Variations in ocular dimensions in a rural population of ethnic Bai,Yi and Han in the Yunnan Province of ChinaPurpose:We aimed to describe the ethnic variations in ocular dimensions among three ethnic groups with similar genetic ancestry living in rural China.Methods:6504 adults(2119 ethnic Bai,2202 ethnic Yi and 2183 ethnic Han)aged 50 years or older participated in the study.Each subject underwent standardized ocular examinations and interviewer-administered questionnaires for risk factor assessment.Central corneal thinkness(CCT)was measured for both eyes using an ultrasound pachymeter.Ocular dimensions including axial length(AL),anterior chamber depth(ACD),vitreous chamber depth(VCD)and lens thickness(LT)were measured using A-scan ultrasonography.Regression and principal component analysis were performed to examine the relationship of ethnicity and other factors with ocular dimensions.Results:The mean CCT readings were 536.4±34.2 ?m in ethnic Bai,532.1±32.1 ?m in ethnic Yi and 529.6 ± 32.7 ?m in ethnic Han adults(P<0.001),respectively.The mean age-and sex-adjusted AL were 23.15±1.23mm,23.04±1.03 mm and 22.95±1.21mm in ethnic Bai,Yi and Han adults,respectively(P<0.001).These figures were 3.42±0.54mm,2.98±0.38mm and 2.86±0.40mm for ACD(P<0.001),15.35±1.35mm,15.73±1.02mm and 15.70±1.26mm for VCD(P<0.001),and 4.35±0.62mm,4.48±0.43 mm and 4.47±0.48mm for LT(P=0.01).Conclusions:This study of more than 6500 multiethnic participants demonstrated a decreasing trend of mean CCT with increasing age across all ethnic groups.There were significant ethnic variations in CCT,with Han ethnicity having the thinnest cornea compared with ethnic minorities.Adults of ethnic Bai had the longer AL(P<0.001),deeper ACD(P<0.001)but shallower VCD(P<0.001)compared with the other two ethnic groups.There were no ethnic variations in LT.Diabetes was associated with shallower ACD.There were significant differences in ocular dimensions among different ethnic groups with small differences in genetics but large variations in cultures and lifestyles.Part 2:Prevalence of glacucoma in a rural population of ethnic Bai,Yi and Han in the Yunnan Province of ChinaPurpose:To estimate the prevalenc of glaucoma in rural multi-ethnic community in the Yunnan Province and to understand the possible difference between Bai,Yi,Han ethnic groups in the prevalenc and type of glaucoma.Methods:The Yunnan Minority Eye Study was conducted from 2011 to 2014 and adopted cluster random sampling strategy.The 8174 older adults aged 50 years or above locating at Dali or Shilin Yi County were selected to receive standardized questionnaire investigation and clinical examination.All subjects was completed the vision acuity check and the intraocular pressure(IOP)measurement.Other ocular dimension was fulfilled with ultrasound equipment including the central corneal thickness(CCT),axial length(AL),anterior chamber depth(ACD),vitrous chamber depth(VCD)and lens thickness(LT).To difine the suspicious subjects according to the intraocular pressure over 21mmHg or some signs found in the fundus observation.All the suspicious subjects should be took fundus photography and visual field examination..Results:There were 6546 participants actually completed glaucoma check including 2133 Bai,2205 Yi and 2208 Han.The response rate was 80.1%in this study.The total age-standardized prevalence of glaucoma was 2.6%in Yunnan Province.The prevalence of primary open-angle glaucoma(POAG)and primary angle-closure glaucoma(PACG)was 1.8%and 0.5%respectively.The prevalence of primary open angle glaucoma(POAG)was significantly higher than the primary angle-closure glaucoma(PACG).The prevalence of all glaucoma in Yi was 4.2%,and the main type of primary open-angle glaucoma(POAG)was 3.2%,and the primary angle-closure glaucoma(PACG)was 0.4%only.The prevalence of glaucoma in Han was 2.6%,and the prevalence of the primary open-angle glaucoma(POAG)and the primary angle-closure glaucoma(PACG)was 1.4%and 0.4%respectively.The lowest prevalence of glaucoma was Bai(2.0%).The prevalence of primary open-angle glaucoma(POAG)and primary angle-closure glaucoma(PACG)was approximately 1.29:1 in Bai.But the prevalence of primary angle-closure glaucoma(PACG)in Bai(0.7%)was the highest among the three ethnic groups.Prevalence of all types of glaucoma was associated with age and gender.Awareness of glaucoma was low in patients(18%).Conclusions:The overall prevalence of glaucoma was 2.6%inYunnan Province,which was agreed with the results of most domestic studies.But the main type of glaucoma was primary open-angle glaucoma(POAG)that suggested the composion of glaucoma in China was changing.There were significant ethnic differences in glaucoma prevalence among Bai,Yi and Han nationalities,as well as various types of glaucoma.The prevention and treatment of glaucoma in Yunnan Province should focus on the elder male Yi population,strengthen the public health education of glaucoma,and improved awareness of glaucoma in the people.