Central Corneal Thickness in Northwestern American Indians/Alaskan Natives and Comparison with White and African-American Persons

Purpose

To determine the demographic factors associated with central corneal thickness (CCT) in Northwestern American Indians/Alaskan Natives (AI/ANs) and to compare these CCT measurements with those of White and African-American persons.

Design

Cross-sectional comparative, observational study.

Methods

We performed ultrasonic pachymetry (DGH-500 Pachette; DGH Technologies, Exton, Pennsylvania, USA) on a random sample of AI/AN subjects from three randomly selected AI/AN tribes in the Northwest United States (n = 429). Pachymetry also was performed on a convenience sample of White (n = 46) and African-American (n = 33) persons. Our main outcome measure was the average of right and left eye CCT.

Results

Average AI/AN CCT was 554.8 ± 33.9 μm. AI/AN CCT was found to be thicker than that of African Americans (528.5 ± 33.2 μm) but similar to that of White persons (551.9 ± 28.3 μm). CCT was greater in AI/AN females than in AI/AN males (557.6 ± 33.3 μm vs 550.1 ± 34.5 μm; P = .03). We found no difference in CCT based on percent AI/AN heritage, age, and keratometry readings. We found no significant differences in mean CCT between AI/ANs with glaucoma (556.2 μm) and those who did not have glaucoma (556.6 μm).

Conclusions

CCT measurements for the Northwest AI/AN population are similar to those of White persons but thicker than those of African-American persons. Although glaucoma is common in AI/ANs, we did not find an association with thin CCT. We need future studies to explore the risk factors for glaucoma in AI/ANs.