Corneal abnormalities in diabetes

To compare corneal thickness and endothelial morphology in patients with diabetes mellitus and age-matched normal subjects, and to determine whether the duration of diabetes mellitus, severity of diabetic retinopathy, and glycemic control are correlated with these measurements.

Single center, case-control study.

Sixty eyes of thirty diabetic patients and sixty eyes of thirty healthy nondiabetic subjects were studied.

Corneal thickness was measured by ultrasonic pachymeter. Corneal endothelial morphology was examined with a contact specular microscope.

Corneal endothelial cell density, mean,cell area, coefficient of variation, percentages of hexagonal cells, and corneal thickness were measured.

There was statistically significant increased corneal endothelial cell density and decreased mean endothelial cell area in the diabetic patients. The diabetic corneas had an increased coefficient of variation of endothelial cell area, a decreased percentage of hexagonal endothelial cell and an increased corneal thickness compared with the control subjects, but these differences were not statistically significant. The duration of diabetes mellitus was significantly correlated with pleomorphism, polymegathism and corneal thickness. Severity of diabetic retinopathy was correlated with endothelial cell density, but these correlations were low. The corneal changes were not correlated with glycemic control.

The diabetic corneas tended to be thicker and had more pleomorphism and polymegathism, though this was not statistically significant. Duration of diabetes mellitus correlated significantly with these corneal changes. This suggests that corneal changes should be evaluated and confirmed before intraocular surgery in chronic diabetic patients.