Central corneal thickness in Northwestern American Indians/Alaskan Natives and comparison with White and African-American persons.

Abstract

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. Cross-sectional comparative, observational study. 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. Average AI/AN CCT was 554.8 +/- 33.9 microm. AI/AN CCT was found to be thicker than that of African Americans (528.5 +/- 33.2 microm) but similar to that of White persons (551.9 +/- 28.3 microm). CCT was greater in AI/AN females than in AI/AN males (557.6 +/- 33.3 microm vs 550.1 +/- 34.5 microm; 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 microm) and those who did not have glaucoma (556.6 microm). 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.