The Effect of Collagen Cross-Linking Procedure on the Material of Intracorneal Ring Segments

Purpose: To assess the potential impact of corneal crosslinking treatment (365nm ultraviolet (UV) A irradiation with riboflavin) on the material properties of Intracorneal Rings Segments (ICRS). Materials and methods: Material properties were studied using FT-IR spectroscopy and UV-Vis spectroscopy. Rings were examined: (1) after installation of riboflavin solution, (2) after irradiation with UV-A light and (3) after instillation of riboflavin solution followed by instillation and coeval irradiation. The experiments followed the standard corneal cross-linking (CXL) protocol of corneal crosslinking treatment. Results: After instillation of riboflavin solution, a permanent intense yellow staining of the samples was observed. UV-Vis spectroscopy confirmed that a certain amount of riboflavin solution was absorbed into the samples after CXL procedure. FT-IR spectroscopic analysis showed alterations in the spectra of ICRS mainly at the 2800-3200 cm(-1) spectral region [modification in band intensities of CH2 (2925cm(-1)) and CH3 (2950cm(-1))]. Conclusions: Our results suggest crosslinking reaction in ICRS material. This should be taken into consideration prior to any CXL treatment of post ICRS-implanted cornea.