Influence of Type 2 Diabetes Mellitus on the Corneal Endothelium and Central Corneal Thickness After Phacoemulsification

Diabetes mellitus may compromise corneal endothelium and increase central corneal thickness, potentially influencing recovery after phacoemulsification. In this retrospective cohort study, we reviewed 45 patients (76 eyes) who underwent phacoemulsification from November 2023 to May 2024. The diabetes group included 36 eyes of patients with type 2 diabetes mellitus, and control group included 40 eyes of non-diabetic patients. Specular microscopy was performed preoperatively and 1 month postoperatively to assess endothelial cell density, percentage of hexagonal cells, coefficient of variation, and central corneal thickness. Endothelial cell density decreased significantly in diabetes group (2577.25 ± 191.22 to 1899.19 ± 682.59 cells/mm²; p < 0.001). In the control group, ECD decreased significantly from 2460.35 ± 307.80 to 1786.18 ± 702.56 cells/mm² (p < 0.001). There was no intergroup difference in endothelial cell density preoperatively (p > 0.05), whereas difference after cataract surgery was significant (p < 0.05). The percentage of hexagonal cells and coefficient of variation did not differ significantly within or between groups (p > 0.05). Central corneal thickness was higher in diabetes group both preoperatively (545.61 ± 32.45 vs 522.74 ± 36.49 μm) and postoperatively (556.32 ± 21.07 vs 536.69 ± 36.63 μm), with significant intergroup differences at both time points (p < 0.05); within-group changes were not significant (p > 0.05). Compared with controls, eyes with type 2 diabetes mellitus showed lower postoperative endothelial cell density and persistently higher central corneal thickness 1 month after phacoemulsification.