Understanding Corneal Transplantation

Side view of eye with inset showing layers of cornea.Corneal transplantation is a surgery to replace a cornea that has problems. The cornea is the eye’s outermost layer. It is a clear, strong layer on the front of your eye. It helps protect your eye from dirt and germs. It also helps control how light enters your eye.

Why a corneal transplantation is done

Some health problems can damage a cornea. It can turn cloudy and not clear (opaque). Its shape can become distorted. These things can harm your eyesight. In some cases, they can even cause blindness. A corneal transplantation removes the damaged cornea and replaces it with one that has been donated. Most people have good eyesight for many years after corneal transplantation.

Some conditions that can damage a cornea and lead to corneal transplantation are:

  • Bulging of the cornea (keratoconus)

  • Swelling of the cornea (bullous keratopathy)

  • Scarring of the cornea

  • Buildup of substances on the cornea (corneal dystrophy)

  • Inflammation of the cornea (keratitis)

  • Infection of the cornea

  • Injury

  • Complications after cataract surgery

Types of corneal transplantation

There are 4 main types of corneal transplantation:

  • Penetrating keratoplasty. A surgeon removes the central part of your damaged cornea. It is replaced with a clear cornea from a donor who has died (deceased donor). This donor cornea is sewn onto the eye. 

  • Deep anterior lamellar keratoplasty.  A surgeon removes the front part of the cornea (the stroma) and replaces it with a clear stroma from a deceased donor

  • Descemet stripping automated endothelial keratoplasty (DSAEK).  A surgeon removes the back part of the cornea (called Descemet's membrane) and the endothelium. They are replaced with endothelium and stroma from a deceased donor.

  • Descemet membrane endothelial keratoplasty (DMEK).  A surgeon removes Descemet's membrane and the endothelium. They are replaced with Descemet's membrane and endothelium from a deceased donor, without stroma.

These surgeries may be full thickness or partial thickness. This is a measure of how much tissue is removed and replaced. Your healthcare provider will tell you which type is best for you.

How corneal transplantation is done

Your procedure will be done by an eye surgeon. The surgery can be done in several ways. The surgeon will remove the central part of your damaged cornea. He or she may use a very fine thread (sutures) to sew the donor cornea in place. Or an air bubble will be put on your eye to keep the new cornea in place. This is used instead of sutures.

Risks of corneal transplantation

All procedures have risks. Risks of corneal transplantation are:

  • New refractive errors (changes in vision) that need correcting with eyeglasses or contact lenses

  • Infection of the cornea

  • Worsening of glaucoma

  • Bleeding in the eye

  • Sore on the eye (ulcer or abscess)

  • Blood vessels growing in the cornea caused by the sutures

  • Detachment of the new cornea

  • Clouding of the eye’s lens (cataract)

  • Detached retina

  • Eye inflammation

  • Surgery fails to fix your eyesight

Another serious risk is rejection of the donor cornea. Your immune system may attack the new cornea. This can cause the transplant to fail. If this happens, you will likely need another corneal transplantation. To lower your risk for rejection, talk with your eye doctor about the symptoms of rejection. Contact your eye doctor if you have any of these symptoms. Early treatment may prevent loss of your eyesight.

Your risks may differ based on your age, your overall health, and the cause of your damaged cornea. Talk with your doctor about which risks apply most to you.