Background: To compare the anterior segment biometric parameters amongst adult American Caucasians, American Chinese and mainland Chinese, in order to determine parameters that may contribute to increased risk for angle closure in Chinese.
Design: Cross-sectional clinic-based study
Participants: Four gender- and age-matched cohorts included Caucasians, American Chinese, Southern and Northern mainland Chinese.
Methods: Anterior segment optical coherence tomography was utilized to image the anterior chamber. Customized software was used to calculate the anterior segment parameters.
Main Outcome Measures: Anterior chamber depth, anterior chamber width, lens vault and corneal arc depth.
Results: Data from 121, 124, 121 and 120 subjects were available for American Caucasian, American Chinese, and Southern and Northern Mainland Chinese subjects, respectively. Caucasians had significantly greater anterior chamber depth, anterior chamber width and corneal arc depth than all Chinese groups even after adjustment for refractive status and axial length. In multiple regression analysis, predictors of greater lens vault were female gender, older age and more hyperopic/less myopic status for both racial groups. It was found only in Chinese that female and older subjects tended to have smaller anterior chamber depth, anterior chamber width and corneal arc depth.
Conclusion: The shallower anterior chamber in Chinese than Caucasians is likely attributable to the shorter corneal arc depth in the former group. Moreover, the smaller anterior chamber width contributes to more crowded anterior chambers in Chinese than in Caucasians. The more anteriorly located lens under a less vaulted cornea in Chinese females compared with Chinese males may account for the higher risk of angle closure in this subpopulation.