Corneal Collagen Crosslinking through Conventional and Transepithelial Technique for Keratoconus

Abstract

Corneal crosslinking is a keratoconus treatment technique that increases corneal rigidity by strengthening it through the photopolymerization of stromal collagen fibers. This effect is achieved through photo-oxidation, which takes place in the stroma after O² is released through the photostimulation of sensitive substances (Riboflavin at 0.1%) after submitting to controlled ultraviolet radiation (uVA3mW/cm²). In order to let the Riboflavin molecule into the stroma with conventional crosslinking, it is necessary to de-epithelize the cornea in an area with a diameter of 9 mm, and which is also 50 to 60 microns deep. seeing as this deepithelization has been associated to pain and higher risk of post-treatment infections, pharmacological vehicles such as carboximetilceluloseorbenzalkoniumchloride have been recently suggested, as they open up the epithelial membrane, weakening cell junctions and allowing passage, absorption and diffusion of the Riboflavin into the stroma, while at the same time preserving the epithelium; this technique is called transepithelial corneal crosslinking. Few studies have been performed in the world and there are no references to the study being performed in south America. In optometry, keeping the epithelium could allow corneal re-shaping through accelerated orthokeratology immediately after treatment, managing to decrease theconical corneal curvature in a stable, not reverting way, reason why interdisciplinary and multidisciplinary work could offer more therapeutic and functional benefits topatients with keratoconus.