title: Association of lens vault with narrow angles among different ethnic groups.
abstract: OBJECTIVE
  To compare lens vault between open-angle and narrow-angle eyes in African-, Caucasian-, Hispanic-, Chinese- and Filipino-Americans.
  
  
  METHODS
  In this prospective study, 436 patients with open angle and narrow angle based on the Shaffer gonioscopic grading classification underwent anterior-segment optical coherence tomography. The Zhongshan Angle Assessment Program was used to calculate lens vault. The narrow-angle group included 32 Chinese-Americans, 22 Filipino-Americans, 26 African-Americans, 24 Hispanic-Americans and 73 Caucasian-Americans. The open-angle group included 56 Chinese-Americans, 29 Filipino-Americans, 45 African-Americans, 27 Hispanic-Americans and 102 Caucasian-Americans. Linear mixed effect regression models, accounting for the use of both eyes and adjusting for age, sex, pupil diameter and spherical equivalent, were used to test for the ethnicity and angle coefficients. Tukey's multiple comparison test was used for pairwise comparisons among the open-angle racial groups.
  
  
  RESULTS
  Significant difference in lens vault was found among the open-angle racial groups (P = 0.022). For the open-angle patients, mean values for the lens vault measurements were 265 ± 288 µm for Chinese-Americans, 431 ± 248 µm for Caucasian-Americans, 302 ± 213 µm for Filipino-Americans, 304 ± 263 µm for Hispanic-Americans and 200 ± 237 µm for African-Americans. Using Tukey's multiple comparison for pairwise comparisons among the open-angle racial groups, a significant difference was found between African-American and Caucasian-Americans groups (P < 0.001). P values for the rest of the pairwise comparisons were not statistically significant. No significant difference was found among the narrow-angle racial groups (P = 0.14). Comparison between the open angle and narrow angle within each racial group revealed significant difference for all racial groups (P < 0.05).
  
  
  CONCLUSIONS
  Among all the ethnicities included in this study, narrow-angle eyes have greater lens vault compared to open-angle eyes. With the exception of the comparison between African-Americans and Caucasian-Americans, differences in lens vault measurements among the racial groups with open angle were statistically insignificant. Our data suggest that other factors may play a greater role in predisposing Asian races to angle closure.
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, CA, USA.
authors.forename: Roland Y
authors.initials: RY
authors.lastname: Lee
authors.forename: Guofu
authors.initials: G
authors.lastname: Huang
authors.forename: Qi N
authors.initials: QN
authors.lastname: Cui
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Shan C
authors.initials: SC
authors.lastname: Lin
mesh_terms: D000368:Aged; D005006:Ethnicity; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis / Q000208:ethnology*; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000208:ethnology*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D007908:Lens, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular