title: Association between baseline angle width and induced angle opening following prophylactic laser peripheral iridotomy.
abstract: OBJECTIVE
  To evaluate the association between baseline angle width and laser peripheral iridotomy (LPI)-induced opening of the anterior chamber angle.
  
  
  METHODS
  Anterior segment optical coherence tomography images captured before and after LPI were analyzed to determine the angle opening distance at 250 μm (AOD250), 500 μm (AOD500), and 750 μm (AOD750) from the scleral spur; trabecular-iris space area at 500 μm (TISA500) and 750 μm (TISA750) from the scleral spur; angle recess area at 750 μm (ARA750) from the scleral spur; and trabecular-iris angle (TIA). Differences in preoperative and postoperative measurements for the anterior chamber angle width parameters were compared by paired Student's t-tests. Univariate and linear mixed-effects regression models were used to examine the association between baseline and LPI-induced opening of anterior chamber angle width parameters.
  
  
  RESULTS
  Eighty-four eyes of 52 primary angle closure suspects were included in the analysis. AOD250, AOD500, AOD750, TISA500, TISA750, ARA750, and TIA significantly increased following LPI by paired Student's t-tests (all P < 0.0001). Lower baseline measurements were significantly associated with greater postoperative opening in all anterior chamber angle width parameters in both univariate and linear mixed-effects regression analyses (all P < 0.05).
  
  
  CONCLUSIONS
  Our results showed significant opening of the anterior chamber angle width after LPI and demonstrated an inverse association between baseline and LPI-induced opening of the anterior chamber angle width, such that eyes with a more crowded anterior chamber angle undergoing LPI had a greater magnitude of increase in anterior chamber angle width after the procedure.
authors: Department of Ophthalmology, University of California, San Francisco, CA 94143-0730, USA.
authors: Roland Y
authors: RY
authors: Lee
authors: Toshimitsu
authors: T
authors: Kasuga
authors: Qi N
authors: QN
authors: Cui
authors: Guofu
authors: G
authors: Huang
authors: Mingguang
authors: M
authors: He
authors: Shan C
authors: SC
authors: Lin
mesh_terms: D000368:Aged; D000867:Anterior Chamber / Q000473:pathology / Q000601:surgery; D001766:Blindness / Q000517:prevention & control*; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000473:pathology / Q000601:surgery*; D006801:Humans; D032801:Iridectomy / Q000379:methods*; D007498:Iris / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000473:pathology / Q000517:prevention & control; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014129:Trabecular Meshwork / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
keywords: angle opening distance; angle recess area; laser peripheral iridotomy; trabecular–iris angle; trabecular–iris space area
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