title: Degree of angle closure and extent of peripheral anterior synechiae: an anterior segment OCT study.
abstract: OBJECTIVE
  To evaluate the relationship between angle width as determined by anterior segment optical coherence tomography (AS-OCT) and the presence of peripheral anterior synechiae (PAS).
  
  
  METHODS
  This was a prospective observational case series in which 203 subjects with primary angle closure or open angles were recruited. Images of the nasal, temporal and inferior angles were obtained with AS-OCT in dark conditions. Subjects then underwent gonioscopy by an independent examiner who was masked to the AS-OCT findings. PAS were identified by gonioscopy and defined as abnormal adhesions of the iris to the angle that were at least half a clock hour in width and present to the level of the anterior trabecular meshwork or higher. The total clock hours of PAS were recorded.
  
  
  RESULTS
  Sixty-eight subjects (33.5%) were PACS, 76 subjects (37.4%) had PAC/PACG, 14 (6.9%) had primary open angle glaucoma, and 45 (22.2%) subjects were normal with open angles. There was a weak but significant correlation between the angle opening distance (AOD), trabecular iris space area (TISA) and angle recess area (ARA) with clock hours of PAS (Spearman's correlation coefficients = -0.30, -0.32 and -0.32, respectively, p<0.001). The mean values of the AOD, TISA and ARA in the nasal, temporal and inferior quadrants were significantly less in eyes with PAS compared with those without (p<0.001, Mann-Whitney U test). Analysis by quadrant showed that these parameters were smaller in the nasal and temporal quadrants in eyes with PAS (p<0.01).
  
  
  CONCLUSIONS
  Angle width determined by AS-OCT and the extent of PAS were weakly correlated, and angle width was significantly smaller in eyes with PAS.
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751.
authors.forename: D H W
authors.initials: DH
authors.lastname: Su
authors.forename: D S
authors.initials: DS
authors.lastname: Friedman
authors.forename: J L S
authors.initials: JL
authors.lastname: See
authors.forename: P T K
authors.initials: PT
authors.lastname: Chew
authors.forename: Y-H
authors.initials: YH
authors.lastname: Chan
authors.forename: W P
authors.initials: WP
authors.lastname: Nolan
authors.forename: S D
authors.initials: SD
authors.lastname: Smith
authors.forename: D
authors.initials: D
authors.lastname: Huang
authors.forename: C
authors.initials: C
authors.lastname: Zheng
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: P J
authors.initials: PJ
authors.lastname: Foster
authors.forename: T
authors.initials: T
authors.lastname: Aung
mesh_terms: D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology*; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000150:complications* / Q000473:pathology*; D006068:Gonioscopy; D006801:Humans; D007499:Iris Diseases / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D000267:Tissue Adhesions / Q000175:diagnosis / Q000209:etiology / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods; D014129:Trabecular Meshwork / Q000473:pathology