Accelerated corneal cross-linking

Corneal cross-linking (CXL) consists in the induction of a tissue biomechanical alteration, which leads to a stiffening, and strengthening of the ectatic corneal tissue. The treatment involves the use of the riboflavin (Vitamin B2) as a photoinducer, an ultraviolet light source and a photochemical reaction that creates a chemical bond between collagen fibrils. The safety of the ultraviolet light parameters depends on wavelength, irradiance and time of irradiation. According to the original standard Dresden protocol, firstly described by Wollensak et al., the maximum efficacy of tissue stiffening is obtained by using 3 mW/cm2 of energy for 30 min, which corresponds to a total energy dose (fluence) of 5.4 J/cm2. The procedure includes the prior epithelium removal and the application of 0.1% riboflavin solution for 30 min followed by 30 min of UVA irradiation.