title: Ethnic difference of the anterior chamber area and volume and its association with angle width.
abstract: OBJECTIVE
  To compare the anterior chamber area/volume (ACA/ACV) and their relationship with the drainage angle between adult Caucasians and Chinese.
  
  
  METHODS
  Study groups were comprised of four age- and sex-matched cohorts: American Caucasians, American Chinese, southern mainland Chinese, and northern mainland Chinese. All subjects were consecutively recruited from general ophthalmology clinics except for southern mainland Chinese participants who were drawn from an ongoing population-based study. Anterior segment optical coherence tomography (ASOCT) images were obtained under dark conditions. Customized software was used to analyze structural indices including ACA/ACV, angle opening distance (AOD), anterior chamber depth (ACD), anterior chamber width (ACW), lens vault (LV), corneal arc depth (CAD), iris thickness (IT), iris curvature (ICurv), and iris area (IArea).
  
  
  RESULTS
  Data from 121, 124, 121, and 120 participants were obtained of American Caucasians, American Chinese, and southern and northern mainland Chinese, respectively. After multiple linear regression analysis, adjusting for age, sex, pupil diameter (PD), and axial length (AL), ACA/ACV was positively associated with ACD, ACW, CAD, and corneal radius of curvature (CR) but negatively related with ICurv and IArea. Ethnic Chinese had significantly smaller ACA (β = -0.18, P = 0.022) and ACV (β = -3.9, P = 0.001) than Caucasians. ACV contributes the most to AOD variation for both Chinese (standardized regression coefficient [SRC] = 0.47, P < 0.001) and Caucasians (SRC = 0.59, P < 0.001).
  
  
  CONCLUSIONS
  Compared with Caucasians, ethnic Chinese had smaller ACA/ACV independent of ACD, ACW, ICurv, IArea, PD, CR, and AL. ACA/ACV is the most prominent contributor to angle width variation for both Chinese and Caucasians in this study.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Wang
authors.forename: Meng
authors.initials: M
authors.lastname: Qi
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Lingling
authors.initials: L
authors.lastname: Wu
authors.forename: Shan
authors.initials: S
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000867:Anterior Chamber / Q000473:pathology*; D005006:Ethnicity; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000208:ethnology* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014481:United States / Q000453:epidemiology