A corneal transplantation is a procedure which replaces damaged tissue on the eye's clear surface.
It is sometimes referred to as a cornea transplant, keratoplasty, or corneal graft. As this type of surgery is a tissue or organ transplantation, viable donor corneas need to be obtained from eye banks.
In addition to conventional corneal transplantation using a full-thickness corneal button to replace the damaged or scarred by corneal tissues, our specialists offer two newer types of corneal transplants
- a deep anterior lamellar keratoplasty (DALK) and a Descemet's stripping endothelial keratoplasty (DSEK).
Deep Anterior Lamellar Keratoplasty
DALK is a partial-thickness corneal transplant that replaces the thinned or scarred corneal stroma (the bulk of corneal tissue) while preserving the two innermost layers of the patient's cornea (Descemet's membrane and the endothelium). The bulk of the patient's diseased outer cornea will be removed and replaced by a healthy donor tissue. The patient's healthy endothelial layer keeps the cornea clear and compact by removing fluid from the bulk of the cornea.
The major advantage of this type of surgery is to retain the patient’s own healthy endothelium without transplanting the donor endothelium. That way it limits the risk of a potentially blinding graft rejection of the donor endothelial cells which may occur with conventional penetrating keratoplasty (full-thickness corneal transplant).
In addition, DALK is a safer alternative to the conventional penetrating keratoplasty because it does not need to cut out the cornea completely to open the eye as in the full-thickness corneal transplantation. DALK can be used in patients with extremely thin corneas (keratoconus or corneal ectasia after LASIK); superficial corneal scarring induced by contact lens or herpes infection; and patients with hereditary corneal stromal dystrophies with corneal opacities.
Descemet's Stripping Endothelial Keratoplasty
DSEK is a partial-thickness corneal transplant that replaces the patient's diseased endothelial cells in the back surface of the cornea while preserving the his/her normal epithelium and stroma (the bulk of corneal tissue) in the outer layers. This procedure involves removing the diseased endothelial layer along with Descemet’s membrane and replacing the innermost corneal layers with a thin tissue layer containing donor endothelial cells.
Because DSEK does not need to open the eye completely during the surgery as in the conventional full-thickness corneal transplantation, DSEK is a safer alternative to the conventional penetrating keratoplasty. The risk of graft rejection is potentially less than the conventional penetrating keratoplasty because only a small amount of donor tissue is transplanted and the majority of the patient's cornea remains in place.
DSEK is a surgical option for patients who have damage to endothelial cells in the inner cornea due to cataract surgery or glaucoma (optic nerve damage from high intraocular pressure) or for those who have hereditary Fuchs’ corneal dystrophy (in which the endothelial cells start to degenerate at much younger ages). Without healthy endothelial cells to pump water out of the eye, the fluid becomes retained in the corneal stroma and causes corneal cloudiness with a decreased vision.
As DSEK does not require stitches to hold the donor tissue in place, it does not induce additional astigmatism (irregular corneal curvatures) and thus has a faster vision recovery time than the conventional penetrating keratoplasty, which does require multiple stitches to secure the donor tissue on host cornea.