IOP, CCT decrease significantly with age in Chinese study

Am J Ophthalmol. 2011;152(3):454-462.

A Chinese population had lower IOP than did similar European cohorts, possibly because of lower body mass index and blood pressure in the Chinese population, a large study found.

"In summary, the distribution of CCT and IOP in our study is similar to that in the majority of East Asian population-based reports," the study authors said. "The IOP distribution, however, is lower than that in most European-derived cohorts, despite similar distributions of CCT."

The Liwan Eye Study, a population-based analysis performed in Southern China, included 1,405 patients. Optical central corneal thickness (CCT), ultrasound CCT, IOP, refractive error, corneal curvature, axial length, body mass index and histories of hypertension and diabetes were analyzed.

Mean age of the 1,348 subjects with IOP data available was 64.8 years. Data from right eyes were analyzed.

Multiple regression models showed that CCT diminished significantly with age (P < .001) and increased with corneal curvature (P < .001) and diabetes (P = .037). Data showed significant positive associations (P < .001) between IOP and greater CCT, body mass index and hypertension.

IOP also declined with age (P = .003). This finding contrasted with many analyses of European populations showing an increase in IOP with age.

Among 65 subjects with ocular hypertension, mean CCT was 555 µm, significantly higher than among subjects with normal IOP (P = .01).

The correlation between ultrasound CCT and IOP in Chinese, Mongolian, Japanese, Latino, Singaporean, Dutch and mixed European populations reported in other studies suggested similar corneal biomechanics across ethic groups, the authors said.