title: Angle-closure glaucoma in Asians: comparison of biometric and anterior segment parameters between Japanese and Chinese subjects.
abstract: OBJECTIVE
  To compare anterior segment parameters in Chinese and Japanese subjects with angle closure using anterior segment optical coherence tomography (ASOCT).
  
  
  METHODS
  One hundred and forty-two Japanese and one hundred and ninety-two Chinese subjects with primary angle closure (PAC) or primary angle-closure glaucoma (PACG) were recruited. All participants underwent A-scan biometry and ASOCT imaging (Visante, Carl Zeiss Meditec, Dublin, CA, USA). Customized software was used to measure ASOCT parameters in horizontal ASOCT scans. The parameters were compared, and multivariate analysis was performed to determine predictors of angle opening distance at 750 μm from the scleral spur (AOD750).
  
  
  RESULTS
  Ethnic difference evaluated by multiple linear regression adjusted for age, gender, spherical equivalent, pupil diameter, and axial length showed that Japanese angle-closure subjects had significantly shallower anterior chamber depth (ACD;β = -0.3, p < 0.001), smaller anterior chamber area (ACA; β = -0.21, p = 0.02) and volume (ACV; β = -0.19, p = 0.01), greater lens vault (LV, β = 0.3, p < 0.001), lens thickness (LT; β = 0.48, p < 0.001), greater iris area (IArea; β = 0.19, p = 0.01), and more curved iris (ICurv; β = 0.16, p = 0.04). The significant determinants of AOD750 were iris thickness (IT; β = -0.21, p = 0.04), ICurv (β = -0.17, p = 0.04), pupil diameter (PD; β = -0.34, p = 0.001) and ACV (β = 0.32, p < 0.001) in Japanese; and IT (β = -0.25, p = 0.001), ACV (β = 0.37, p < 0.001), PD (β = -0.26, p = 0.001), and LV (β = -0.18, p = 0.03) in Chinese.
  
  
  CONCLUSIONS
  Compared to Chinese, Japanese angle-closure eyes have smaller and more crowded anterior segment with thicker lenses. ACV, IT, and PD are important factors for angle width in both races. These results suggest possible ethnic differences in angle-closure mechanism(s).
authors: Singapore Eye Research Institute and Singapore National Eye Center, 11 Third Hospital Avenue, Singapore, 168751, Singapore.
authors: Henrietta
authors: H
authors: Ho
authors: Mineo
authors: M
authors: Ozaki
authors: Takanori
authors: T
authors: Mizoguchi
authors: Shamira A
authors: SA
authors: Perera
authors: Daniel H
authors: DH
authors: Su
authors: Mingguang
authors: M
authors: He
authors: Tien Y
authors: TY
authors: Wong
authors: Monisha E
authors: ME
authors: Nongpiur
authors: Tin
authors: T
authors: Aung
mesh_terms: D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology*; D044466:Asian People / Q000208:ethnology*; D001699:Biometry; D002681:China / Q000453:epidemiology; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000208:ethnology* / Q000473:pathology* / Q000601:surgery; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D032801:Iridectomy; D007564:Japan / Q000453:epidemiology; D053685:Laser Therapy; D008297:Male; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology
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