A Study of Central Corneal Thickness and Corneal Endothelial Changes in Type 2 Diabetes Mellitus

Abstract

BACKGROUND Corneal endothelium plays an important role in maintaining the corneal transparency. Evaluation of corneal endothelial cell morphology and central corneal thickness (CCT) is important in a wide range of disorders. Type 2 diabetes mellitus is one of the emerging health problems which also affects the corneal endothelial morphology and CCT. Aims and Objectives-To compare CCT and corneal endothelial changes in type 2 diabetics and non-diabetic controls and to assess their correlation with duration of diabetes and HbA1c levels. MATERIALS AND METHODS A total of 200 eyes of type 2 diabetic subjects and 200 eyes of non-diabetic age and gender matched controls, presenting to the Department of Ophthalmology, Christian Medical College, Ludhiana were included in the study. The study was conducted over a period of one year and eight months. The CCT and corneal endothelial changes were measured using a specular microscope. Data was analysed using SPSS software version 21 using independent t-test, chi-square test and Spearmen correlation test. RESULTS The diabetic subjects had increased central corneal thickness, less endothelial cell density and more standard deviation and hexagonality of the corneal endothelium than the non-diabetic controls (P<0.05). Coefficient of variation for cell size was significantly higher for diabetics (P<0.05). It was observed that the central corneal thickness and corneal endothelial parameters had statistically significant correlation with the duration of diabetes mellitus. Whereas when correlated with HbA1c only CCT and CV had a statistically significant correlation (p=0.041 and p=0.001 respectively). CONCLUSION Diabetics have thicker corneas, less corneal endothelial cell density and hexagonality, and more irregular cell size. Therefore, routine assessment of central corneal thickness and corneal endothelial structure may be beneficial in all diabetic patients along with retinopathy assessment.