title: Screening for primary angle closure in Mongolia: a randomised controlled trial to determine whether screening and prophylactic treatment will reduce the incidence of primary angle closure glaucoma in an east Asian population.
abstract: OBJECTIVE
  To describe the methods used and initial results of a prospective study designed to determine whether screening and prophylactic treatment will reduce the incidence of primary angle closure glaucoma (PACG) in Mongolia.
  
  
  METHODS
  A total of 4725 individuals aged 50 years and above were recruited to the study and randomised to intervention or control groups. All subjects had non-mydriatic optic disc examination. The intervention arm had measurement of anterior chamber depth (ACD) by A-scan ultrasound and intraocular pressure (IOP) with Tonopen. Gonioscopy was performed on test positive cases (ACD <2.53 mm or IOP >or=24 mm Hg either eye). Those with occludable angles were offered laser iridotomy. Primary outcome will be incidence of PACG at 5 year follow up.
  
  
  RESULTS
  Glaucoma was diagnosed in 128 (2.7%) subjects. Of the remaining 4597, 2293 were randomised to intervention. Intervention as allocated was received by 2280 (99.4%) individuals. 160 (23.4%) of 685 test positive cases had occludable angles, of which 156 were treated with iridotomy.
  
  
  CONCLUSIONS
  This trial is a further step in determining whether screening and prophylactic treatment for primary angle closure in east Asian populations will reduce the incidence of glaucoma.
authors.affiliation: Department of Epidemiology and International Eye Health, Institute of Ophthalmology, London, UK. winnienolan@hotmail.com
authors.forename: W P
authors.initials: WP
authors.lastname: Nolan
authors.forename: J
authors.initials: J
authors.lastname: Baasanhu
authors.forename: A
authors.initials: A
authors.lastname: Undraa
authors.forename: D
authors.initials: D
authors.lastname: Uranchimeg
authors.forename: S
authors.initials: S
authors.lastname: Ganzorig
authors.forename: G J
authors.initials: GJ
authors.lastname: Johnson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D008986:Mongolia / Q000453:epidemiology; D009898:Optic Disk / Q000473:pathology; D011446:Prospective Studies