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Standard Epithelium-Off CXL Procedure

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(A) Standard “epithelium-off” CXL procedure: Following fully informed consent, CXL is typically performed under topical anaesthesia. In the standard epithelium-off technique the central 8–9 mm of the corneal epithelium is debrided to enable adequate stromal Riboflavin absorption (Caporossi et al., 2006). Following epithelial debridement, Riboflavin 0.1%, suspended in a dextran T500 20% solution, is applied every 3–5 min for at least 20 min to allow sufficient stromal absorption prior to UVA exposure (Wollensak et al., 2003a). Intra-operative pachymetry is advocated by many surgeons to monitor corneal thickness prior to UVA exposure and apply hypotonic Riboflavin drops if it thins excessively during Riboflavin administration. The central 8–9 mm of the cornea is then irradiated with UVA, at 3 mW/cm2 for 30 min. After treatment, topical …show more content…

Spoerl confirmed the need for complete central epithelial debridement to allow sufficient stromal absorption of Riboflavin and reported no changes in the biomechanical properties of corneal tissue where the CXL was performed with the epithelium intact (Spoerl et al., 2000). Despite these findings, some clinicians have chosen to perform CXL with the epithelium intact (Chan et al., 2007) or partially disrupted (Samaras and Lake, 2010) or with the use of femtosecond-created intra-stromal pockets in an attempt to reduce post-operative discomfort and help visual recovery (Kanellopoulos, 2009). The use of repeated applications of tetracaine 1% to try to loosen epithelial tight junctions has been tried (Chan et al., 2007). Other investigators have utilized limited full-thickness epithelial debridement in a grid pattern, with remaining islands of intact epithelium to aid post-operative epithelial healing (Samaras and Lake,

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