title: Risk of acute angle closure and changes in intraocular pressure after pupillary dilation in Asian subjects with narrow angles.
abstract: OBJECTIVE
  To evaluate the risk of primary acute angle closure (AAC), changes in intraocular pressure (IOP), and associated risk factors after pupil dilation in Asian subjects with narrow angles (primary angle-closure suspects [PACS]).
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  A total of 471 subjects aged more than 50 years with narrow angles in Singapore.
  
  
  METHODS
  This study was part of a prospective trial of PACS. Subjects underwent a detailed ophthalmic evaluation including gonioscopy, biometry, pachymetry, and ultrasound biomicroscopy. All subjects underwent pupil dilation with 1% tropicamide eye drops at the baseline visit, before any laser or medical intervention. Intraocular pressure was measured using Goldmann applanation tonometry by the same observer before and 1 hour after pupil dilation. A dose of oral acetazolamide was given before the patient left the clinic.
  
  
  METHODS
  Intraocular pressure before and after dilation, and an AAC event.
  
  
  RESULTS
  The mean age of the 471 subjects was 63.0 ± 6.9 years (mean ± standard deviation); 75.4% were women, and 92.8% were Chinese. Of the 471 participants, 3 (0.64%; 95% confidence interval [CI], 0.13-1.85) developed AAC within 6 hours of dilation despite pretreatment with oral acetazolamide. Twenty-two subjects (4.67%; 95% CI, 2.95-6.99) showed a postdilation increase in IOP of ≥ 5 mmHg in either eye, 6 subjects (1.27%; 95% CI, 0.47-2.75) had an IOP increase of ≥ 8 mmHg in either eye, and 4 subjects (0.85%; 95% CI, 0.23-2.16) had a postdilation IOP of >25 mmHg in either eye. Narrower gonioscopic angle width, that is, having a lower mean gonioscopic modified Shaffer grading (coefficient β -0.51; standard error 0.19; P=0.01), and predilation IOP level (coefficient β -0.17; standard error 0.04; P < 0.001) were significant risk factors for IOP increase after dilation in multivariate linear regression analysis.
  
  
  CONCLUSIONS
  The risk of AAC among Asian subjects with narrow angles was low after pupillary dilation with tropicamide and oral acetazolamide prophylaxis. The presence of narrower angle width by gonioscopy was the only clinical parameter identified for a significant IOP increase after pupil dilation.
authors: Singapore Eye Research Institute and Singapore National Eye Center, Singapore.
authors: Raghavan
authors: R
authors: Lavanya
authors: Mani
authors: M
authors: Baskaran
authors: Rajesh S
authors: RS
authors: Kumar
authors: Hon-Tym
authors: HT
authors: Wong
authors: Paul T K
authors: PT
authors: Chew
authors: Paul J
authors: PJ
authors: Foster
authors: David S
authors: DS
authors: Friedman
authors: Tin
authors: T
authors: Aung
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage; D000208:Acute Disease; D000368:Aged; D044466:Asian People; D001699:Biometry; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000453:epidemiology* / Q000503:physiopathology / Q000601:surgery; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D032801:Iridectomy; D007498:Iris / Q000601:surgery; D053685:Laser Therapy; D008297:Male; D033401:Microscopy, Acoustic; D008875:Middle Aged; D009184:Mydriatics / Q000008:administration & dosage*; D011446:Prospective Studies; D011680:Pupil / Q000187:drug effects*; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D014065:Tonometry, Ocular; D014331:Tropicamide / Q000008:administration & dosage
chemical_list: D009184:Mydriatics; D014331:Tropicamide; D000086:Acetazolamide