title: Ultrasound biomicroscopic features associated with angle closure in fellow eyes of acute primary angle closure after laser iridotomy.
abstract: OBJECTIVE
  To investigate the frequency of appositional angle closure and related anatomic characteristics in fellow eyes of Chinese subjects with acute primary angle closure (APAC) after laser peripheral iridotomy (LPI).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Consecutive subjects with APAC presenting from April 2006 to September 2006 at the Glaucoma Service of Peking University Eye Center, Peking University Third Hospital.
  
  
  METHODS
  Under dark conditions, fellow eyes were divided into 2 groups based on the detection of appositional angle closure by ultrasound biomicroscopy (UBM). For all subjects, UBM parameters were measured to evaluate the different anatomic features between the 2 groups. Darkroom provocative tests (DRPTs) and gonioscopy were performed to investigate the relationship between angle closure and intraocular pressure.
  
  
  METHODS
  Central anterior chamber depth (ACD); angle opening distance(500) (AOD(500)); angle recess area(750) (ARA(750)); trabecular-iris angle (T-I angle); trabecular-ciliary process distance (TCPD); peripheral iris thickness (IT(1)); iris-zonule distance (IZD); and the position of the iris insertion.
  
  
  RESULTS
  Thirty-four post-LPI fellow eyes of 34 patients with APAC (8 men, 26 women; mean +/- standard deviation age 66.3+/-7.2 years, range 54-83) were included. Peripheral anterior synechiae (PAS) were not observed in any subject. Appositional angle closure was observed in at least 1 quadrant in 13 (38.2%) of the 34 patients. Compared with eyes without appositional closure, eyes with appositional closure showed significantly lower AOD(500), ARA(750), and T-I angle in 4 quadrants; shorter TCPD in the inferior and temporal quadrants; and thicker IT(1) in the superior and nasal quadrants (P<0.05). The DRPT results were positive in 3 (11.1%) of 27 eyes with appositional closure in 0 to 2 quadrants and in 3 (75.0%) of 4 eyes with appositional closure in 3 to 4 quadrants (P = 0.0164).
  
  
  CONCLUSIONS
  Under dark conditions, more than one third of fellow eyes of APAC showed appositional angle closure after LPI. The anatomic findings indicate a narrower angle, a more anterior position of the ciliary body, and a thicker peripheral iris in fellow eyes of APAC after LPI may be associated with an increased risk for progressive angle closure.
authors.affiliation: Peking University Third Hospital, Peking University Eye Center, Beijing, PR China.
authors.forename: Bao-qun
authors.initials: BQ
authors.lastname: Yao
authors.forename: Ling-ling
authors.initials: LL
authors.lastname: Wu
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000000981:diagnostic imaging*; D002924:Ciliary Body / Q000000981:diagnostic imaging; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000000981:diagnostic imaging* / Q000601:surgery; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D032801:Iridectomy / Q000379:methods*; D007498:Iris / Q000000981:diagnostic imaging* / Q000601:surgery; D053685:Laser Therapy; D008297:Male; D033401:Microscopy, Acoustic; D008875:Middle Aged; D014065:Tonometry, Ocular; D014129:Trabecular Meshwork / Q000000981:diagnostic imaging*