It is a treatment for patients diagnosed with Keratoconus, which can be applied in the initial phase or as a complementary therapy for the intrastromal corneal rings.
For this procedure, the cornea is first impregnated with vitamin B2 or Riboflavin, and later Ultraviolet (UV) radiation is applied. The combination of Riboflavin and UV radiation produces strengthening of (strengthens) the corneal collagen, increasing the union between the collagen molecules, and thus preventing the progression of the Keratoconus. This procedure is performed at the operating room, in a sterile environment, with topic (topical) anesthesia and ambulatory care. 
The main objective of the crosslinking treatment is to bring the progression of the Keratoconus to a halt, to regulate the corneal topography, and to enhance the effect of the intrastromal corneal rings, all of which improve the quality of the patient's vision. In addition, this procedure can be applied as well to other corneal disorders such as pellucid marginal degeneration, post-lasik ectasia, corneal ulcers, bullous keratopathy, etc.
Riboflavin is applied to the cornea after depithelization of the area, which promotes a better absorption of the vitamin. This vitamin works, on the one hand, as a source of free radicals to produce the crosslinking reaction and, on the other, as a barrier that prevents the UV rays from penetrating the deep corneal layers as well as from affecting other parts of the eye such as the crystalline lens and the retina.