Purpose To compare anterior segment parameters between eyes of Chinese and Caucasians using anterior segment optical coherence tomography and to evaluate the association between these parameters and anterior chamber angle width between the two ethnic groups.
Methods 60 Chinese and 60 Caucasians, 30 with open angles and 30 with narrow angles (defined as Shaffer grade ≤2 in ≥3 quadrants during dark room gonioscopy) in each group, were consecutively enrolled. One eye of each subject was randomly selected for imaging in a completely darkened room. Measurements, including anterior chamber depth (ACD), scleral spur-to-scleral spur distance (anterior chamber width (ACW)), anterior chamber angle width, iris convexity and iris thickness, were compared between the groups. The associations between angle opening distance and biometric measurements were evaluated with univariate and multivariate regression analyses.
Results There were no differences in age, axial length, anterior chamber angle measurements, pupil diameter and iris convexity between Chinese and Caucasians in both open-angle and narrow-angle groups. However, the ACD and ACW were smaller and the iris was thicker in Chinese. In the multivariate analysis, the ACD was the most influential biometric parameter for angle opening distance in both Chinese and Caucasians. After adjusting the effects of axial length, age and sex, ACD and ACW were significantly smaller in Chinese.
Conclusions Chinese eyes had smaller ACD, smaller ACW and greater iris thickness than Caucasians. ACD was the most influential parameter in determining the angle width in both ethnic groups.
- Anterior chamber angle
- anterior segment biometry
- scleral spur-to-scleral spur distance
- anterior segment optical coherence tomography
- anterior chamber depth
- primary angle closure
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Funding Educational Foundation of America, Westport, Connecticut, USA.
Competing interests CL, RR, JL and RW have received research support in the form of instruments from Heidelberg Engineering.
Ethics approval This study was conducted with the approval of the Clinical Research Ethics Committee in Hong Kong and New York.
Provenance and peer review Not commissioned; externally peer reviewed.