Confocal microscopy in corneal crosslinking

Conventional riboflavin ultraviolet A (UVA) cross-linking (CXL) represents an evolving therapy for the conservative treatment of progressive keratoconus and postoperative ectasia.1,2 The physiochemical basis3,4 of conventional CXL lies in the photodynamic type I to II reactions induced by the interaction between 0.1% riboflavin molecules absorbed in corneal tissue and UVA rays delivered at a 5.4 J/cm2 energy dose for 30 minutes, releasing reactive oxygen species that mediate cross-link formation between and within collagen fibers, increasing biomechanical corneal resistance against ectasia and intrinsic anticollagenase activity.5-8 Since a conventional CXL procedure (3 mW/cm2 for 30 minutes8) requires a long overall time (approximately 50 to 60 minutes), new high irradiance accelerated CXL (ACXL) treatment protocols based on the physical principles stated in Bunsen-Roscoe law of reciprocity have been recently investigated