title: [The prevalence and its screening methods of primary open angle glaucoma in defined population-based study of rural and urban in Beijing].
abstract: OBJECTIVE
  The purpose of the study is to determine the prevalence of primary open-angle glaucoma (POAG) in persons aged 40 or above in Beijing, China.
  
  
  METHODS
  From June 2001 to October 2001, the screening population was identified by a door-to-door census in five metropolitan resident areas in the north of Beijing and three villages in a county south to Beijing. The screening included visual acuity, frequency doubling perimetry (FDP, C-20 screening program), non-contact tonometry, slit lamp microscopy, anterior chamber depth (Van Herick method), and fundus photography. The suspect glaucoma and definite glaucoma patients were asked to have an examination of Octopus 1-2-3 perimetry (G1X TOP threshold program), repeat tonometry, gonioscopy and fundus stereo-photography at Beijing Tongren Hospital.
  
  
  RESULTS
  There were 4451 subjects who were examined at the study sites. The response rates in rural and urban were 79.58% and 87.13%, respectively. In this 40 years-old or above population, the prevalences of POAG were 1.97% in rural men, 2.07% in urban men, 1.04% in rural women and 1.42% in urban women. In this study, 92.30% POAG patients in rural and 87.30% POAG patients in urban were new diagnosed cases. The prevalence of POAG increased with age and the change was exponential. In 50% POAG patients first IOP measurement was less than 21 mm Hg (1 mm Hg = 0.133 kPa). The prevalence of monocular eye blindness was 15.40% and 10.90% in rural and urban, respectively.
  
  
  CONCLUSIONS
  Owing to use fundus photography and integrated evaluation of optic disc, it is possible to diagnose in earlier stage of POAG. This study identifies more patients with POAG than any previous population-based studies of China, and is similar to other studies of Asia such as in India and Singapore. The reason of lower POAG prevalence in rural women than in urban may be that the anterior chamber depth of rural women is shallower than that of urban women. It may cause difficult to differentiate the chronic primary angle closure glaucoma from POAG at screening sites, so the part POAG patients may be included in primary angle closure glaucoma patients.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Ophthalmic Center, Capital University of Medical Sciences, Beijing 100730, China. xuliang@public.bta.net.cn
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Chen
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Luo
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Rong-Xiu
authors.initials: RX
authors.lastname: Zhang
authors.forename: Xiu-Ying
authors.initials: XY
authors.lastname: Sun
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Zheng
authors.forename: Wei-Xian
authors.initials: WX
authors.lastname: Song
authors.forename: Yu-Ying
authors.initials: YY
authors.lastname: Shi
authors.forename: Shi-Yuan
authors.initials: SY
authors.lastname: Zhang
authors.forename: Bao-Chen
authors.initials: BC
authors.lastname: Sun
authors.forename: Jia-Liang
authors.initials: JL
authors.lastname: Zhao
authors.forename: Bin-Rong
authors.initials: BR
authors.lastname: Ma
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D005260:Female; D005451:Fluorescein Angiography; D005902:Glaucoma, Open-Angle / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data; D017678:Sex Distribution; D014065:Tonometry, Ocular; D014505:Urban Population / Q000706:statistics & numerical data; D015351:Vision Screening / Q000379:methods*