Intraoperative OCT for Monitoring Corneal Pachymetry during Corneal Collagen Cross-Linking for Keratoconus

Biomechanical reinforcement of the cornea by collagen cross-linking (CXL) using riboflavin and ultraviolet A (UV-A) irradiation is a well-established treatment for halting the progression of keratoconus. Corneal pachymetry is one of the most important factors with respect to the safety of CXL. In addition to the initial pachymetric changes, significant changes in corneal pachymetry may occur during the different steps of the procedure, highlighting the role of intraoperative pachymetric measurements. Intraoperative optical coherence tomography (OCT) can be used safely and effectively to monitor the corneal pachymetry during CXL. Among the advantages of this technology is its ability to provide a more detailed profile of the corneal thickness in a noncontact manner compared to the ultrasound method. These features are especially advantageous for monitoring corneal pachymetry in the setting of CXL in KCN patients, considering the marked irregularity of the epithelium and stroma in these patients. OCT has also been used for evaluation of other aspects of the CXL procedure like evaluation of in vivo riboflavin penetration in to the corneal stroma