A cornea transplant is an operation to replace part of the cornea with corneal tissue from a donor. This operation is sometimes called keratoplasty. The cornea is the transparent, dome-shaped surface of the eye. Light enters the eye through the cornea. It plays a large role in the eye’s ability to see clearly.

A cornea transplant may:

• Restore vision.
• Reduce pain.
• Improve the appearance of a damaged or diseased cornea.

Most cornea transplant operations are successful. But cornea transplant carries a small risk of complications, such as rejection of the donor cornea.

Why it’s done

A cornea transplant is most often used to restore vision to a person with a damaged cornea. A cornea transplant also can relieve pain or other symptoms associated with cornea diseases.

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

• A cornea that bulges outward, called keratoconus.
• Fuchs dystrophy, a genetic condition.
• Thinning or tearing of the cornea.
• Cornea scarring, caused by infection or injury.
• Swelling of the cornea.
• Corneal ulcers not responding to medical treatment.
• Complications caused by previous eye surgery.

Risks

Cornea transplant is relatively safe. Still, it does carry a small risk of serious complications, such as:

• Eye infection.
• Pressure increase within the eyeball, called glaucoma.
• Problems with the stitches used to secure the donor cornea.
• Rejection of the donor cornea.
• Bleeding.
• Retinal problems, such as retinal detachment or swelling.

Symptoms of cornea rejection

The body’s immune system can mistakenly attack the donor cornea. This is called rejection. Rejection might require medical treatment or another cornea transplant.

Make an urgent appointment with your eye doctor if you notice symptoms of rejection, such as:

• Loss of vision.
• Eye pain.
• Red eyes.
• Sensitivity to light.

Rejection occurs in about 10% of cornea transplants.

How you prepare

Before cornea transplant surgery, you will undergo:

• A thorough eye exam. Your eye doctor looks for conditions that might cause complications after surgery.
• Measurements of your eye. Your eye doctor determines what size donor cornea you need.
• A review of all medications and supplements you’re taking. You may need to stop taking certain medications or supplements before or after your cornea transplant.
• Treatment for other eye problems. Unrelated eye problems, such as infection or swelling, can reduce your chances of a successful cornea transplant. Your eye doctor will treat those problems before your surgery.

Finding a donor cornea

Corneas used in transplants come from people who have died. Corneas from people who died from unknown causes are not used. Corneas from people who had previous eye surgery, eye disease or certain conditions, such as diseases that are passed from one person to the next, also are not used.

Unlike people who need organs such as livers and kidneys, people needing cornea transplants don’t require tissue matching. In the United States, donor corneas are widely available, so there’s usually not a long waiting list.

Operations to transplant a portion of the cornea

A cornea transplant removes either the entire thickness or the partial thickness of the diseased cornea and replaces it with healthy donor tissue. Your cornea surgeon will decide which method to use. These types of operations include:

• Penetrating keratoplasty. This operation involves a full-thickness cornea transplant. Your surgeon cuts through the entire thickness of the irregular or diseased cornea to remove a small button-sized disk of corneal tissue. A special instrument is used to make this precise circular cut.

  The donor cornea, cut to fit, is placed in the opening. Your surgeon then uses stitches, also called sutures, to keep the new cornea in place. The stitches might be removed at a later visit with your eye doctor.

• Endothelial keratoplasty. There are two types of endothelial keratoplasty. These operations remove diseased tissue from the back corneal layers. The layers include the endothelium and a layer of tissue called the Descemet membrane, which is attached to the endothelium. Donor tissue replaces the removed tissue.

  The first type of operation, called Descemet stripping endothelial keratoplasty (DSEK), uses donor tissue to replace up to one-third of the cornea.

  The second type of operation, called Descemet membrane endothelial keratoplasty (DMEK), uses a much thinner layer of donor tissue. The tissue used in DMEK is extremely thin and fragile. This operation is more challenging than DSEK but is commonly used.

• Anterior lamellar keratoplasty (ALK). Two different methods remove diseased tissue from the front corneal layers, including the epithelium and the stroma. However, they leave the back endothelial layer in place.

  The depth of cornea damage determines the type of ALK operation that’s right for you. Superficial anterior lamellar keratoplasty (SALK) replaces only the front layers of the cornea. This leaves the healthy stroma and endothelium intact.

  A deep anterior lamellar keratoplasty (DALK) operation is used when cornea damage extends deeper into the stroma. Healthy tissue from a donor is then attached to replace the removed portion of the cornea. This process is known as grafting.

• Artificial cornea transplant. If you aren’t eligible for a cornea transplant with a donor cornea, you might receive an artificial cornea. This operation is known as keratoprosthesis.