Central corneal epithelial thickness in diabetic patients: a cross-sectional study

Purpose of the study: a cross-sectional study was conducted to compare the central corneal epithelial thickness (CCET) between patients with diabetes mellitus (DM) and age and gender matched controls. We also explored correlation between CCET and duration of DM, DM control and severity of diabetic retinopathy (DR).

Material and methods. The study included 111 diabetics aged 57.62 ± 11.02 years and 111 controls of comparable age — 53.74 ± 15.98 years who underwent a comprehensive ophthalmology evaluation. Optical coherence tomography of anterior segment was performed on all participants to measure the central corneal thickness (CCT) and CCET. Demographic data and data on duration of DM and blood sugar control were recorded.

Results. The mean CCT was significantly higher in diabetics (Mean = 514.8 ± 31.15 μm) compared to controls (Mean = 500.87 ± 32.34 μm; p-value = 0.001 with 95% CI 5.527 to 22.33). The mean CCET was lower in cases (Mean = 50.15 ± 4.49 μm) compared to controls (Mean = 50.6 ± 5.67 μm; p-value = 0.513) however, it was not statistically significant. A significant difference in CCT was observed between controls and patients with severe nonproliferative DR and proliferative DR (p = 0.034), but no significant difference in CCET was found between any subgroups of degree of DR (p > 0.05). There was no correlation between CCET and Hb_A1с levels and duration of DM.

Conclusion. CCET showed no significant difference between diabetics and controls. There is no correlation between CCET and blood sugar control and duration of DM. Hence, corneal epithelial thickness may not be a contributory factor for diabetic keratopathy.

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