A healthy cornea ? the transparent, dome-shaped surface of your eye ? is an essential component of sharp, clear vision. It accounts for a large part of your eye's focusing power. Any condition that distorts your cornea or diminishes its transparency can harm your vision ? sometimes severely. One treatment option may be a cornea transplant (keratoplasty).

Cornea transplants are one of the most common organ and tissue transplants performed.

A number of conditions can be treated with a cornea transplant, including:

• Thinning of the cornea

• Cornea scarring, caused by infection or injury

• Clouding of the cornea

• Swelling of the cornea

• Corneal ulcers, including those caused by infection.
  

 

In the most common type of cornea transplant — called penetrating keratoplasty — your surgeon cuts through your entire cornea to remove a small button-sized disc. An instrument that acts like a cookie cutter, called a trephine, makes this precise circular cut. The donor cornea, cut to fit, is placed in the opening. Your surgeon then uses a fine thread to stitch the new cornea into place. The stitches are removed at a later visit to your eye doctor. The entire surgery takes about an hour, depending on your individual condition.

With some types of cornea problems, a full-thickness transplant isn't always the best treatment. Partial-thickness (lamellar) transplants may be used in certain situations.

 

• Deep lamellar transplant. This transplant replaces only the innermost of your cornea's five layers. A small incision is made in the side of your eyeball to allow for removal of your cornea's inner layer without injuring the outer layers. A donor graft replaces the removed portion. This procedure is still being studied.

• Surface lamellar transplant. Although it's very uncommon, eye damage may only involve the outer layers of the cornea. These layers, too, can be removed and replaced with a donor graft.

What are the risks of cornea transplant?

Cornea transplants are relatively safe and have been performed for many years. But, like any surgery, cornea transplants carry the risk of complications. Common signs and symptoms that might represent complications include:

• Decreased vision

• Increased reddening of your eye

• Pain

• Sensitivity to light

• Light flashes or floaters.
  

Though rare, serious complications can occur, including:

• Infection

• Wound problems, such as a broken stitch, which can be uncomfortable and impede healing

• Imperfections on the outermost layer of the cornea, which can cause haze or scarring

• Bleeding

• Swelling in the front of the eye, including inflammation of the iris (iritis)

• Glaucoma — abnormally high pressure inside your eyeball, which can lead to optic nerve damage and vision loss