A corneal transplantation is a surgical procedure where the irregular or opaque central area of the cornea is replaced by a donated one.
Replacement of the full-thickness of the central cornea area:
Appearance immediately after surgery :
Appearance after a few months :
The transplantation may concern the anterior part: it is then an anterior lamellar graft, indicated in the anterior opacities. This graft is sutured to the surface of the cornea after removing the opaque or irregular portion using a keratome.
LThe graft may concern the posterior part: it is then a posterior lamellar graft, indicated in the endothelial alterations. In this case the graft is inserted into the anterior chamber: the endothelium is removed (Descemet’s Stripping Endothelial Keratoplasty).
An artificial anterior chamber is necessary to prepare the lamellar graft :
Preparation of the corneal flap to be grafted: the cornea is put on the artificial chamber, cut with the keratome, and the trephine
Before and after intervention :
Profile view: posterior graft placed on the posterior surface of the receiving cornea
This treatment aims at reinforcing the bonds between the corneal collagen fibers in order to increase strength of the cornea.
Strengthening the cornea is interesting in case of keratoconus, or of post-LASIK ectasia, or corneas at risk for ectasia. It can stabilize the cornea increasing the resistance.
The principle of corneal collagen cross-linking is to use UV light and a photo-sensitizer, the riboflavin, to strengthen chemical bonds between the collagen fibers.
After removing the corneal epithelium, riboflavin is applied to the cornea and into the stroma in about 30 minutes.
The cornea is then exposed to ultraviolet light (wavelength 365 m) for 30 minutes with a special lamp and watered with riboflavin every two minutes.
The cornea is then protected by a contact lens and a bandage. Antibiotic eye drops and artificial tears are prescribed. The corneal epithelium heals in 2 or 3 days.