Keratoplasty

What is keratoplasty?

A corneal transplant or keratoplasty is the transplantation of corneal tissue from a donor to a recipient. This is usually required when the optical features of the recipient’s cornea are deteriorating to such an extent that the formation of a clear image at the back of the eye is impossible. Transplantation is also required if the cornea is damaged either by disease or accident. A corneal transplant allows for most of the affected cornea to be surgically removed and replaced with a healthy, perfectly formed replica of the donor’s cornea. This in turn allows for the restoration of sight in the affected eye. The only source of donor cornea is from a deceased human donor.

Indications

There are many conditions in which corneal transplantation may be considered. The two most common reasons are :

• pseudophakic bullous keratopathy , which is a generic term for corneal oedema with epithelium raised in blisters. It involves a loss of clarity and clouding over of the cornea, due to the gradual impairment of the endothelial cells responsible for keeping the cornea clear and healthy. It can occur for many reasons including hereditary susceptibility, previous eye surgery, or just simply advancing years. 

• or to the loss of the smooth rounded shape of the cornea meaning that light cannot be regularly focused into the eye, as occurs in Keratoconus.

Other problems which may require a transplant include a malfunction of the inner layer of the cornea (Fuchs’ dystophy), hereditary or congenital corneal clouding.
Injury to the cornea can occur because of chemical burns, mechanical trauma, or infection by viruses, bacteria, fungi, or protozoa. Herpes virus is one of the more common infections leading to corneal transplant. 
Surgery would only be used when damage to the cornea is too severe to be treated with corrective lenses.

Success of corneal transplantation

Corneal transplantation (keratoplasty) is the most successful of all tissue or organ transplants. However, factors such as glaucoma, retinal degeneration, or optic nerve disease may affect the final visual result even if the surgery is successful. The success rate of corneal transplantation depends on the cause of the corneal clouding. For example, corneal transplantation for degeneration or swelling, and those for keratoconus both have high success rates ( greater than 90%), while corneal transplants for chemical burns have lower success rates (approximately 65%).

Corneal tissue for transplantation comes from an Eye Bank. The health of the donor material is carefully inspected before it is used for corneal transplantation.

More about keratoplasty

The operation
Possible risks