Corneal transplantation is a surgery that removes your damaged cornea and replaces it with healthy cornea tissue from a donor.

The cornea is the clear outer layer that covers the front of your eye. It helps protect the rest of your eye from germs and debris. It also helps focus light into your eye. Different health problems can damage your cornea. They can make it cloudy (opaque) or change its shape. If this happens, your vision can get worse. In some cases, corneal diseases can even lead to blindness.

The types of corneal transplantation include:

• Endothelial keratoplasty. This is the most common form of the surgery. It's a type of partial-thickness corneal transplantation. Only the inner layer of the cornea is removed. It's replaced with a very thin layer of corneal tissue from a donor who has died (cadaver donor).
• Penetrating keratoplasty. This is the oldest form of corneal transplantation. It's now done less often. The center part of your damaged cornea is removed. It's replaced with a clear full-thickness cornea from a cadaver donor.

If you have scarring or damage to your cornea, your vision can be damaged. Your eye doctor may need to treat the underlying cause of the damage to your cornea. If the damage is severe enough, you might also need corneal transplantation to fix your sight. Conditions that might require this procedure include:

• Bullous keratopathy.
• Problems from cataract surgery.
• Corneal dystrophy.
• Corneal scar.
• Corneal swelling.
• Infection of the cornea.
• Corneal injury.
• Keratitis.
• Keratoconus.

If the damage to your cornea is minor, it may heal on its own. You may not need this procedure. If you have a very badly damaged cornea, a procedure called phototherapeutic keratectomy may be another option. This method uses a laser to etch away part of your damaged cornea. But this method is not right for all types of cornea damage.

If you need corneal transplantation, ask your eye doctor if a full-thickness or partial-thickness transplantation would be best for you. Talk with them about the treatment that makes the most sense for you.

All procedures have risks. Some possible risks of this procedure include:

• Bleeding.
• Cataracts.
• Corneal infection.
• Detachment of the new cornea.
• Inflammation.
• New refractive errors, requiring glasses or contact lenses.
• Glaucoma getting worse.
• Severe infection inside the eye (endophthalmitis).
• Severe infections on the surface of the eye (eye ulcer or abscess).
• Retinal detachment.

There is also a risk that the surgery won't work and that you will have impaired vision.

Another major possible problem is rejection of the donated cornea. Your immune system might recognize that the tissue is foreign. It may start to attack the tissue. This can cause the transplant to fail. If this happens, you will likely need another procedure. To reduce your risk of vision loss from rejection, ask your eye doctor about the symptoms of rejection. If you have any of these symptoms, see your eye doctor right away. Early treatment may prevent vision loss.

Your risk for problems from this surgery may be different based on your age, your other health conditions, and the reason for your corneal transplantation. Ask your eye doctor about your own risks for corneal transplantation.

Your eye doctor will give you information about how to get ready for corneal transplantation. You may need to stop taking certain medicines before the procedure. Follow any directions you are given for not eating or drinking before the surgery.

Your eye doctor may want to use special tools to shine a light in your eye and examine your cornea. You may need to have your eyes dilated for this eye exam. You also might need computerized corneal mapping. This will give your eye doctor more information about your cornea.

Talk with your eye surgeon about what will happen during your surgery. The details may vary. In general, during the procedure:

• You may be given general anesthesia to put you to sleep. If this is the case, you will sleep deeply through the surgery and won't remember it afterward.
• In other cases, you may be awake but drowsy during the surgery. You will be given medicine to help you relax. In this case, your doctor may use anesthetic eye drops and shots (injections) to make sure you don't feel anything.
• Your surgeon will remove the central part of your damaged cornea.
• If you have penetrating keratoplasty, your surgeon will use a very fine thread to sew the new donated cornea in place. If you have endothelial keratoplasty, your surgeon will place an air or gas bubble inside your eye to keep the new tissue in place, instead of stitches (sutures) or thread.
• An antibiotic ointment may be applied to your eye to help prevent infection.
• Your eye will be patched and covered.

Ask your eye doctor about what to expect after your surgery. In most cases, you will be able to go home the same day. Plan to have someone go home with you after the procedure.

Follow your eye doctor's instructions about eye care and medicines. You may need to take antibiotic eye drops to help prevent infection. Your eye may be a little sore after the procedure. But you should be able to take over-the-counter pain medicines. You may need to wear an eye patch for a day or so. You will also need to take medicines to prevent rejection of your new cornea. Ask your eye doctor if you should not do any certain activities as you recover. Don't rub your eyes.

You will need close follow-up care to monitor your condition and find out how well the procedure worked. You may have a scheduled appointment the day after the procedure. Your stitches may be removed at a follow-up visit. But this might not be until much later.

Tell your eye doctor right away if you have any signs of problems, including rejection. These might include symptoms such as:

• Decreased vision.
• More pain.
• More redness.
• More sensitivity to light.

Before you agree to the test or the procedure, make sure you know:

• The name of the test or procedure.
• The reason you are having the test or procedure.
• What results to expect and what they mean.
• The risks and benefits of the test or procedure.
• What the possible side effects or complications are.
• When and where you are to have the test or procedure.
• Who will do the test or procedure and what that person's qualifications are.
• What would happen if you did not have the test or procedure.
• Any alternative tests or procedures to think about.
• When and how you will get the results.
• Who to call after the test or procedure if you have questions or problems.
• How much you will have to pay for the test or procedure.