Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans, and Japanese in a glaucoma clinic.
ABSTRACT To characterize the central corneal thickness (CCT) of Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American patients in a multiethnic glaucoma practice.
Retrospective study (chart review).
Glaucomatous (n = 600) and nonglaucomatous (n = 201) eyes of 801 patients examined in a San Francisco glaucoma clinic from June 2002 to April 2004 who met inclusion criteria were included in the study. The 6 racial (ethnic) groups represented in the study were Caucasian (n = 186, 23.2%), Chinese (n = 157, 19.6%), Japanese (n = 121, 15.1%), Hispanic (n = 116, 14.5%), Filipino (n = 114, 14.2%), and African American (n = 107, 13.4%).
Central corneal thickness was measured by means of ultrasound pachymetry in Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American participants with glaucomatous and normal eyes. The relationship between CCT and race was investigated using multivariate regression analyses, controlling for confounders. One eye of each of 801 participants was included for analysis.
Correlation of mean CCT with race, glaucoma diagnosis, age, spherical equivalent, gender, and history of ocular surgery.
The mean CCT of all participants was 542.9 mum. Central corneal thicknesses of Chinese (555.6 microm), Caucasian (550.4 microm), Filipino (550.6 microm), and Hispanic (548.1 microm) participants did not significantly differ. The CCT of Japanese participants (531.7 microm) was significantly less than that of Caucasians, Chinese, Filipinos, and Hispanics (all, P< or =0.001) and greater than that of African Americans (P = 0.03). African Americans had a CCT (521.0.0 microm) less than that of all races (P< or =0.05). Glaucoma suspects and patients with normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and chronic angle-closure glaucoma (CACG) had corneas significantly thinner than those of normal participants (P< or =0.004), whereas ocular hypertensives had significantly thicker corneas (P<0.0001). Among all participants, decreasing values of CCT were significantly related to older age (P<0.01). Less negative or more positive refractive errors, gender, and history of ocular surgery were not associated with changes in CCT (P = 0.38, P = 0.50, and P = 0.97, respectively).
Studies examining individual Asian subpopulations in isolation suggest that differences in CCT may exist among different Asian groups. The results of this study indicate that CCT does, in fact, vary among Asian subpopulations; Japanese have thinner corneas than Chinese and Filipinos. Caucasians, Chinese, Hispanics, and Filipinos have comparable CCT measurements, whereas the corneas of African Americans are significantly thinner. Additionally, older individuals; glaucoma suspects; and participants with NTG, POAG, PEX, and CACG have thinner corneas. Ocular hypertensives, however, have thicker corneas.
- SourceAvailable from: Prakash AdhikariJournal of Clinical Research and Ophthalmology. 11/2014; 1(2):107.
- [Show abstract] [Hide abstract]
ABSTRACT: Purpose: The purpose of this study is to provide better understanding of the Ocular Response Analyzer (ORA) and how reliable it is to produce intraocular pressure (IOP) measurements that are free of the effects of corneal stiffness parameters, and stiffness estimates that are independent of IOP. Materials and Methods: A numerical parametric study that closely represents the in-vivo conditions of the human eye and the ORA procedure was conducted to determine the correlation coefficient r2 between ORA output and the values of true IOP and a number of stiffness parameters, namely corneal thickness, curvature and age. For the purpose of this exercise, the ORA output was put in the form k1P1+k2P2 where k1 and k2 were variables and P1 and P2 were ORA’s measured applanation pressures. Two separate clinical datasets involving Moorfields Eye Hospital, London and the University of New South Wales, Sydney participants, respectively, were used to validate the numerical results. Results: The numerical study results show a strong association between (k1P1 + k2P2) and the true IOP over a wide range of k1 and k2 values apart from a narrow region approximately extending from (k1 = +2, k2 = −2) to (k1 = −2, k2 = +2). On the other hand, (k1· P1 + k2· P2) was found to have a strong association with CCT, R and age (the stiffness parameters) over the same narrow region, beyond which the association was weak. Similar trends were found with the two clinical datasets. Conclusions: The results of this study show the potential of the ORA to provide reliable IOP measurements with weak dependence on the cornea’s stiffness parameters and the considerably reduced reliability in producing stiffness estimates that are unaffected by IOP values.Current Eye Research. 12/2014;
- [Show abstract] [Hide abstract]
ABSTRACT: Background: Few, and inconsistent, studies have showed high heritability of some parameters of the anterior segment of the eye; however, no heritability of anterior chamber volume (ACV) has been reported, and no study has been performed to investigate the correlation between the ACV and central corneal thickness (CCT). Methods: Anterior segment measurements (Pentacam, Oculus) were obtained from 220 eyes of 110 adult Hungarian twins (41 monozygotic and 14 same-sex dizygotic pairs; 80% women; age 48.6 ± 15.5 years) obtained from the Hungarian Twin Registry. Results: Age- and sex-adjusted heritability of ACV was 85% (bootstrapped 95% confidence interval; CI: 69% to 93%), and 88% for CCT (CI: 79% to 95%). Common environmental effects had no influence, and unshared environmental factors were responsible for 12% and 15% of the variance, respectively. The correlation between ACV and CCT was negative and significant (r ph = -0.35, p < .05), and genetic factors accounted for the covariance significantly (0.934; CI: 0.418, 1.061) based on the bivariate Cholesky decomposition model. Conclusion: These findings support the high heritability of ACV and central corneal thickness, and a strong genetic covariance between them, which underscores the importance of identification of the specific genetic factors and the family risk-based screening of disorders related to these variables, such as open-angle and also angle closure glaucoma and corneal endothelial alterations.Twin research and human genetics : the official journal of the International Society for Twin Studies. 10/2014; 17(5):397-404.