title: Prevalence of primary angle closure and primary angle-closure glaucoma in a southwestern rural population of Japan: the Kumejima Study.
abstract: OBJECTIVE
  To determine the prevalence and ocular biometry of primary angle closure (PAC) and primary angle-closure glaucoma (PACG) in a rural population in southwestern Japan.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  All residents aged 40 years or older in Kumejima, Okinawa, Japan.
  
  
  METHODS
  Of the 4632 residents 40 years of age or older, 3762 (participation rate, 81.2%) underwent a detailed ocular examination, including measurement of the best-corrected visual acuity, slit-lamp examination, Goldmann applanation tonometry, static and dynamic gonioscopy, undilated stereoscopic optic fundus photographs, autorefractometry, partial coherence laser interferometry, noncontact specular microscopy, and screening visual field (VF) testing using frequency-doubling technology. If glaucoma or related or other ocular disorders were suspected, the subject was referred for a definitive examination including VF testing with the 24-2 Swedish Interactive Thresholding Algorithm Standard program of the Humphrey Field Analyzer (Carl Zeiss Meditec, Dublin, CA).
  
  
  METHODS
  Prevalence rates of primary angle-closure suspects (PACS), PAC, PACG, and PACG suspects.
  
  
  RESULTS
  Under the standard definitions of the International Society of Geographical and Epidemiological Ophthalmology, the prevalence rates of PACS, PAC, and PACG were 8.8%, 3.7%, and 2.0%. Extending the diagnosis of PAC and PACG to include people with narrow but open angles and primary peripheral anterior synechiae, the prevalence rates of PAC and PACG increased to 6.0% and 2.2%, respectively. Hence, broadening the diagnostic categories in PAC and PACG increased the prevalence rates by 62% and 10%. Twenty-three subjects (0.6%; 95% confidence interval, 0.4%-0.9%) had a history of or were diagnosed with acute PAC. Older age, female gender, hyperopic refractive error, short axial length, and shallow anterior chamber depth were independent predictors of an occludable angle.
  
  
  CONCLUSIONS
  The prevalence of PACG in Kumejima (2.2%) was one of the highest reported in population-based studies, that is, 3.7 times higher than in the Tajimi Study carried out in an urban center located in the central area of the main island of Japan.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan. sshoichi@med.u-ryukyu.ac.jp
authors.forename: Shoichi
authors.initials: S
authors.lastname: Sawaguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakai
authors.forename: Aiko
authors.initials: A
authors.lastname: Iwase
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Haruki
authors.initials: H
authors.lastname: Abe
authors.forename: Goji
authors.initials: G
authors.lastname: Tomita
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000869:Anterior Eye Segment / Q000473:pathology*; D001699:Biometry; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis / Q000453:epidemiology*; D006068:Gonioscopy; D006306:Health Surveys; D006801:Humans; D007429:Intraocular Pressure; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012029:Refraction, Ocular; D012424:Rural Population / Q000706:statistics & numerical data*; D058609:Visual Field Tests; D014794:Visual Fields