Corneal thickness variation seen among Asian subpopulations

In a study in a multiethnic population in San Francisco, people of Japanese descent were seen to have thinner corneas than their Chinese and Filipino counterparts. Researchers said the differences in corneal thickness observed among the Asian subpopulations in this study help to confirm differences suggested by earlier studies of the groups in isolation.

Elsa Aghaian and colleagues reviewed the charts of 186 white, 157 Chinese, 121 Japanese, 116 Hispanic, 114 Filipino and 107 black patients seen at one glaucoma clinic. Of these patients, 600 had glaucoma and 201 did not. One eye of each patient was included for analysis.

Central corneal thickness was measured by ultrasound pachymetry, and the relationship between central corneal thickness and race was investigated using regression analysis. The main outcome measures were the mean correlation of central corneal thickness with race, diagnosis of glaucoma, age, spherical equivalent, gender and history of ocular surgery.

The mean central corneal thickness of all participants was 542.9 µm. Mean thicknesses did not significantly differ between the eyes of the Chinese, white, Filipino and Hispanic participants. The mean central corneal thickness of the eyes of the Japanese patients was significantly less than the means of those four groups. Blacks had the lowest mean central corneal thickness of any of the groups, significantly thinner than the Japanese mean.

Participants with normal tension glaucoma, primary open-angle glaucoma, pseudoexfoliation glaucoma and chronic angle-closure glaucoma had corneas significantly thinner than participants with normal eyes. Participants with ocular hypertension had significantly thicker corneas than those without (P < .0001).

The study is published in the December issue of Ophthalmology.