title: Detection of narrow angles and established angle closure in Chinese residents of Singapore: potential screening tests.
abstract: OBJECTIVE
  To assess the performance of peripheral and central anterior chamber depth (ACD) measurements, and autorefraction, in identifying Chinese people with occludable drainage angles or established primary angle closure.
  
  
  METHODS
  Population-based cross-sectional analysis.
  
  
  METHODS
  Subjects aged 40 years and older were drawn from a representative sample of Chinese Singaporean residents. Limbal chamber depth (LCD) was estimated and central ACD was measured using optical pachymetry and ultrasound. An autorefraction was taken for all subjects. Angle width and the presence of peripheral anterior synechiae were determined by gonioscopy. Receiver operating characteristic curves were generated to show the performance of these tests in detecting occludable angles.
  
  
  RESULTS
  A total of 1090 subjects were examined. The prevalence of occludable angles was 6.5%. LCD measurement performed best in detecting occludable angles (area under the curve [AUC] 0.904, 95% confidence interval [CI] 0.870, 0.937). Optical pachymetry and ultrasound measurement of ACD performed less well (AUC 0.859 and 0.810, respectively), and autorefraction performed poorly in detecting occludable angles (AUC 0.632). LCD also gave the best performance in detecting primary angle closure (AUC 0.782, 95% CI 0.727, 0.837).
  
  
  CONCLUSIONS
  Limbal LCD estimation outperforms other methods of measuring ACD as a screening tool for the detection of occludable drainage angles in the Chinese population of Singapore.
authors.affiliation: Department of Ophthalmology, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074. winnie_nolan@yahoo.com
authors.forename: Winifred P
authors.initials: WP
authors.lastname: Nolan
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
authors.forename: David
authors.initials: D
authors.lastname: Machin
authors.forename: Peng T
authors.initials: PT
authors.lastname: Khaw
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Johnson
authors.forename: Steve K L
authors.initials: SK
authors.lastname: Seah
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Foster
mesh_terms: D000328:Adult; D000368:Aged; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000473:pathology*; D019540:Area Under Curve; D044466:Asian People / Q000208:ethnology*; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological; D005189:False Positive Reactions; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000208:ethnology*; D006068:Gonioscopy; D006801:Humans; D016850:Limbus Corneae / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012846:Singapore / Q000453:epidemiology; D014463:Ultrasonography