Corneal Collagen Cross-Linking (CCR)

Corneal collagen crosslinking (CXL) is a minimally invasive procedure often performed via surgery that prevents progression of corneal ectasia, which is forward bulging of the cornea, and works on specific types such as keratoconus and post-LASIK ectasia. The process of cross-linking of the collagen is best described as the ability of collagen fibrils to form strong bonds with other adjacent fibers, and this crosslinking often occurs naturally through age via an oxidative deamination reaction, and this can often occur prematurely leading to conditions such as ectasia. Three main components form the mechanism behind CXL: a photosynthesizer that absorbs light energy via the corneal stroma at a wavelength of 370 nm, a UV light source, specifically UV-A light exposure, and the resulting photochemical reaction, consisting of reactive oxygen species that generate covalent bonds between collagen molecules and with collagen and peptidoglycan,. This procedure is approved for individuals who have keratoconus, the thinning of the cornea over time, and post-LASIK ectasia, where the cornea bulges forward after various eye surgeries such as SMILE, LASIK, OR PRK surgery. Although the procedure is expensive (starting at $2,500), it can prevent the need for more serious surgery. 

Before and after CXL side-by-side depicting the change in the strength of collagen interactions

https://eyewiki.aao.org/Corneal_Collagen_Cross-Linking#:~:text=Corneal%20collagen%20cross-linking%20is%20a%20technique%20which%20uses,irregular%20changes%20in%20corneal%20shape%20known%20as%20ectasia.

https://www.allaboutvision.com/conditions/corneal-crosslinking.htm

https://www.hopkinsmedicine.org/wilmer/services/cornea/cxl.html