Is there a correlation between diabetes mellitus and central corneal thickness?

PURPOSE: To evaluate the association of central corneal thickness (CCT) with diabetes mellitus and compare it with age and sex-matched healthy controls. MATERIALS AND METHODS: This study included 245 eyes of 245 subjects (one eye per subject). One hundred diabetic patients constituted the study group and 145 were healthy controls. The study group was subdivided into 3 subgroups: subgroup 1 (no diabetic retinopathy), subgroup 2 (nonproliferative diabetic retinopathy), and subgroup 3 (proliferative diabetic retinopathy). CCT was determined with ultrasonic pachymeter. None of the patients had glaucoma, retinal laser treatment, and history of ocular surgery. Statistical analyses were performed by analysis of variance and Kruskall-Wallis tests. Correlation analysis was performed to assess the association between disease duration and glycosylated hemoglobin levels among subgroups. RESULTS: Demographic characteristics of study and control groups were similar (P>0.05). The mean CCT was significantly greater in study group (564±30 μm) compared with control group (538±35 μm) (P=0.001). In addition, mean CCT was found to be greater in subgroup 3 (582±23 μm) compared with subgroups 1 (565±32 μm) and 2 (558±31 μm); but the difference did not reach statistical significance (P=0.056). Also, there was no significant correlation in respect to the level of glycosylated hemoglobin and disease duration among the subgroups. CONCLUSIONS: We found that the central cornea of diabetic patients is thicker when compared with nondiabetic patients. Thicker central cornea associated with diabetes mellitus should be taken into consideration while obtaining accurate intraocular pressure measurements in diabetics.