title: Configuration of the drainage angle, intraocular pressure, and optic disc cupping in subjects with chronic angle-closure glaucoma.
abstract: OBJECTIVE
  To investigate the relationship between drainage angle configuration with untreated intraocular pressure (IOP) and optic disc cupping in subjects with chronic angle-closure glaucoma (CACG).
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  Two hundred seventy-five Asian subjects with CACG who participated in a randomized controlled trial that investigated the IOP-reducing effect of latanoprost and timolol.
  
  
  METHODS
  Chronic angle-closure glaucoma was defined as the presence of glaucomatous optic neuropathy (with or without a visual field defect), an anterior chamber angle in which the pigmented trabecular meshwork was not visible for at least 180 degrees on gonioscopy, and evidence of peripheral anterior synechiae (PAS) in association with elevated IOP of 21 mmHg or more. Static and dynamic gonioscopy were performed, the angles were graded in each quadrant according to the Shaffer scheme, and the number of clock hours of PAS was recorded. The untreated IOP and vertical cup-to-disc ratio were correlated with mean angle width and extent of PAS.
  
  
  METHODS
  Mean angle width, clock hours of PAS, IOP, and vertical cup-to-disc ratio.
  
  
  RESULTS
  Most subjects were female (75%), and the mean age was 62.9+/-9.4 years. The mean angle width was 0.77+/-0.53 and the mean number of clock hours of PAS was 4.77+/-3.2 hours. Untreated IOP correlated with angle width (r = -0.23; P<0.001) and clock hours of PAS (r = 0.22; P<0.001). Vertical cup-to-disc ratio also correlated with angle width (r = -0.17; P = 0.004) and PAS (r = 0.28; P<0.001). Performing a multiple linear regression using baseline IOP as the outcome variable with age, gender, clock hours of PAS, and angle width as predictors, there was a 0.39-mmHg (95% confidence interval, 0.15-0.63) increase in baseline untreated IOP for each unit increase in clock hours of PAS (P = 0.002).
  
  
  CONCLUSIONS
  In subjects with CACG, the extent of PAS and a narrower width of the drainage angle were associated with higher untreated IOP and a larger vertical cup-to-disc ratio.
authors.affiliation: Glaucoma Department, Singapore National Eye Centre, Singapore. tin11@pacific.net.sg
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
authors.forename: Marcus C C
authors.initials: MC
authors.lastname: Lim
authors.forename: Yiong-Huak
authors.initials: YH
authors.lastname: Chan
authors.forename: Prin
authors.initials: P
authors.lastname: Rojanapongpun
authors.forename: Paul T K
authors.initials: PT
authors.lastname: Chew
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000378:metabolism / Q000473:pathology*; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001082:Aqueous Humor / Q000378:metabolism; D002908:Chronic Disease; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000188:drug therapy; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D000077338:Latanoprost; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000188:drug therapy; D011446:Prospective Studies; D011461:Prostaglandins F, Synthetic / Q000627:therapeutic use; D013999:Timolol / Q000627:therapeutic use; D014129:Trabecular Meshwork / Q000378:metabolism / Q000473:pathology*
chemical_list: D000959:Antihypertensive Agents; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost; D013999:Timolol