Assessment of the Effect of Corneal Collagen Cross-Linking on Corneal Endothelium in Patients with Keratoconus

Background: Keratoconus, was a non-inflammatory, conical ectasia of cornea that often exhibits bilateral asymmetric progression over time. Objective: Evaluation of corneal endothelium alterations subsequent to Corneal Collagen Cross-linking (CXL) for management of progressive keratoconus. Patients and methods: Included 30 eyes from twenty-four individuals diagnosed with keratoconus. Endothelial cell density (ECD), coefficient of variation (CV) and percentage of hexagonal cells (HEX) evaluated by specular microscopy. Together with central corneal thickness (CCT) recorded by using Pentacam. All were evaluated prior to CXL and one month subsequent. Results: One month after CXL, the mean ECD increased from 2740.87 ± 202.56 cells/mm² to 2751.20 ± 226.35 cells/mm². The mean HEX also increased from 66.23 ± 7.54% preoperatively to 66.70 ± 7.979% postoperatively. Additionally, the mean CV decreased from 29.35 ± 4.306% preoperatively to 28.95 ± 4.495% postoperatively. However, changes in ECD, HEX, CV weren`t statistically significant (p=.281, p=.229, p=.052 respectively). CCT decreased from a mean of 476.01 ± 44.03 μm pre-CXL to 471.95 ± 43.33 μm one-month post-CXL, but again this difference was not statistically significant (p=0.06). No statistically significant relationships among duration of procedure, amount of energy and changes in CCT, ECD & HEX or CV (P > .05). Furthermore, the correlation between keratoconus stage and changes in CCT, HEX, and CV didn`t reveal any statistically significant relationships (P > .05). Conclusions: No substantial alterations were seen in corneal endothelial characteristics, as assessed by specular microscopy, after cross-linking in keratoconic eyes.