Corneal thickness and intraocular pressure in the Barbados Eye Studies

Objectives: To describe the distribution of central corneal thickness (CCT) and evaluate its relationship to intraocular pressure (IOP) in the predominantly black population of the Barbados Eye Studies (BES). Methods: Participants received a standardized examination, including pachymetry, applanation tonometry, and a comprehensive ophthalmologic evaluation. Analyses were based on data from all eyes, and generalized estimating equation methods were applied to account for the correlation between eyes. Results: Among the 1142 consecutive participants with pachymetry measurements, the mean age was 64.3 years, and 58% were women. Black participants tended to have thinner corneas (mean thickness, 529.8 μm) than mixed (black and white) (537.8 μm) and white participants (545.2 μm), respectively. Among black participants, increasing values of CCT were significantly related to younger age (P<.001), diabetes history (P=.03), and refractive error (P=.03); a marginally significant relationship (with thinner corneas) was found with a clinical diagnosis of glaucoma (P=.07). Intraocular pressure was not associated with CCT in this population. Conclusions: Although other studies have reported a positive correlation between CCT and IOP, such a relationship was not substantiated in the black BES population. Black participants tended to have thinner corneas than white participants, whereas younger individuals, as well as those with a history of diabetes and more positive refractive errors, had thicker corneas.