Cross-linking is a medical procedure that combines the use of ultra-violet light and riboflavin eye drops. In a cross-linking procedure, Riboflavin (vitamin B2) is dripped onto the cornea and then exposed to ultra violet light. The light causes the riboflavin to fluoresce, which leads to the formation of bonds between collagen molecules or collagen cross-linking. The Avedro KXL Accelerated Cross-linking procedure is performed in minutes, while traditional procedures typically take one hour.
Recently the ophthalmology community has seen a marked increase in the prominence of corneal collagen cross-linking as a treatment strategy for progressive keratoconus and post-lasik ectasia. This interest has arisen from a body of evidence documenting the biomechanical and cellular changes induced by cross-linking. The findings of this research provide a rationale for its use in keratoconus to retard the progression of this disease. A rapidly growing number of clinical reports suggest a consistent stabilizing effect of cross-linking along with a variable improvement in corneal shape and visual function in some patients. As a first-line treatment the greatest aim of cross-linking is to reduce and stop keratoconus in the early phase of the condition, and to treat the progressive vision loss that occurs which can lead to corneal transplantation.
 Grant R Snibson FRANZCO; Collagen cross-linking: a new treatment paradigm in corneal disease – a review; Clinical and Experimental Ophthalmology 2010; 38: 141–153 doi: 10.1111/j.1442-9071.2010.02228.x