Influence of diabetes mellitus on corneal thickness

Introduction. Ultrastructural changes in corneas of patients with diabetes mellitus have been previously described. Objective. The aim of this study was to compare central corneal thickness (CDR) values in diabetic patients without retinopathy at the stage of diabetic nonproliferative and proliferative retinopathy and CDR in a control group of healthy subjects. Methods. The study included 121 diabetic patients and 125 healthy subjects matched according to gender and age. Each patient underwent ophthalmological examination involving a dilated fundus examination and CDR measurement using the ultrasound pachymeter. The eyes of diabetic patients were classified according to Early Treatment Diabetic Retinopathy Study into three groups: without diabetic retinopathy (NDR), with nonproliferative diabetic retinopathy (NPDR) and a group with proliferative diabetic retinopathy (PDR). Only one eye of each subject was chosen for the study. Results. The mean CDR value was significantly higher in the diabetic group (570.52±31.81 μm) compared with the control group (541.42±27.82 μm). The difference between the two groups was statistically significant (p<0.0001). The highest mean CDR value was recorded in the PDR group (585.97±28.58 μm), followed by the NPDR group (570.84±30.27 μm), whereas the lowest mean CDR value was recorded in the NDR group (559.80±31.55 μm). There was a statistically significant difference in CDR between the NDR and PDR groups, as well as between the NPDR and PDR groups (p<0.001, p<0.05 respectively). No significant difference was recorded between the NDR and NPDR groups (p>0.05). Conclusion. CDR of diabetic patients was higher compared to healthy subjects. The highest mean value of CDR was registered in the PDR group, followed by the NPDR and the NDR groups