title: Biometric Factors Associated With Acute Primary Angle Closure: Comparison of the Affected and Fellow Eye.
abstract: OBJECTIVE
  To compare ocular biometric and anterior segment parameters between the affected and fellow eye in subjects with acute primary angle closure (APAC).
  
  
  METHODS
  We evaluated 76 subjects with unilateral APAC who had undergone bilateral laser peripheral iridotomy before enrollment. Imaging was done using anterior segment optical coherence tomography and a customized software was used to measure the following: angle opening distance (AOD750); trabecular-iris space area (TISA750); iris thickness (IT750); iris curvature (ICURV); iris area (IAREA); anterior chamber depth; area and volume (ACD; ACA and ACV); anterior chamber width (ACW); anterior vault (ACD+LV); lens vault (LV); and pupil diameter (PD). We used A-scan ultrasonography to measure axial length (AL) and lens thickness (LT). Mean differences in ocular biometric and anterior segment parameters were assessed using linear mixed model adjusting for PD.
  
  
  RESULTS
  A total of 53 subjects (36 females, 67.9%) with a mean age of 62.7 ± 8.1 years were analyzed after excluding 17 unanalyzable images in at least one eye. Affected eyes had shallower ACD, smaller ACA, ACV, anterior vault, TISA750, AOD750, and ICURV (all P < 0.05). Axial length, ACW, LV, LT, IAREA, and IT750 did not differ between the eyes. In the affected eyes, IT750 was significantly associated AOD750 (P < 0.05); whereas in the fellow eyes, IT750 and AL was predictive of AOD750 (all P < 0.05).
  
  
  CONCLUSIONS
  Eyes with previous APAC had smaller anterior segment dimensions when compared with their fellow eyes. Iris thickness was the strongest predictor of angle width in both affected and fellow eyes.
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Eray
authors.initials: E
authors.lastname: Atalay
authors.affiliation: Singapore Eye Research Institute, Singapore 2Duke-NUS Graduate Medical School, Singapore.
authors.forename: Monisha E
authors.initials: ME
authors.lastname: Nongpiur
authors.affiliation: Singapore Eye Research Institute, Singapore 2Duke-NUS Graduate Medical School, Singapore.
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Singapore National Eye Centre, Singapore.
authors.forename: Shamira A
authors.initials: SA
authors.lastname: Perera
authors.affiliation: Singapore Eye Research Institute, Singapore 3Singapore National Eye Centre, Singapore 4Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
mesh_terms: D000208:Acute Disease; D000869:Anterior Eye Segment / Q000473:pathology*; D001699:Biometry; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000503:physiopathology; D006068:Gonioscopy / Q000379:methods; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D041623:Tomography, Optical Coherence / Q000379:methods*