Corneal endothelial morphology in type 2 diabetes mellitus, a comparative study among Nepalese population

To access and compare the corneal endothelial morphology between type two diabetic patients (T2DM) and non-diabetic controls, and to explore their associations with diabetes duration, HbA1c levels and severity of diabetic retinopathy in a Nepalese cohort as diabetes can lead to morphological changes in the corneal endothelium, yet data specific to the Nepalese population remain limited. A hospital-based, cross-sectional, comparative study was conducted involving 220 eyes (110 diabetic and 110 control). Non-contact specular microscopy (NIDEK CEM-530) was employed to access endothelial cell parameters, including endothelial cell density (ECD), coefficient of variation (CV), percentage of hexagonal cells (HEX), and central corneal thickness (CCT). Diabetic corneas exhibited significantly lower ECD (2728.68 ± 216.40 vs. 2847.74 ± 194.97 cells/mm², p < 0.001) and HEX (64.93 ± 4.88% vs. 66.15 ± 4.09%, p = 0.0045), alongside higher CV (32.49 ± 4.26% vs. 31.01 ± 3.08%, p = 0.003) and CCT (545.63 ± 29.93 μm vs. 534.32 ± 27.29 μm, p = 0.004). Longer duration of diabetes (≥ 10 years) correlated with reduced ECD (p = 0.013). Eyes with DR demonstrated more pronounced endothelial dysfunction, (p < 0.05). HEX showed a negative correlation with HbA1c (p = 0.038). T2DM significantly alters corneal endothelial morphology and function, with worsening changes associated with prolonged diabetes, poor glycemic control, and advanced DR. These findings underscore the need for routine endothelial evaluation in diabetic patients to mitigate surgical risks and monitor corneal health.