The cornea is the clear part that covers the eye. It helps you to see by focusing the light into the eye. The cornea is made of layers of cells. These layers work together in order to protect your eye and provide clear vision.
Descemet’s membrane
Layers of the cornea, the clear part that covers the eye.
There are different types of corneal transplants. In some instances, only the front and middle layers of the cornea are removed. In others, only the inner layer is replaced. Sometimes, the entire cornea needs to be removed.
What causes cornea problems?
Eye disease and injuries can damage the cornea. Here are some of the usual eye problems that can lead to a damaged cornea:
- Keratoconus, is when the cornea is cone-shaped rather than dome-shaped
- Fuchs’ dystrophy, when cells in the inner layer of the cornea are not working properly
- Eye infections or injuries that cause scarring in the cornea
- Last corneal surgery or other eye surgery that damaged the cornea
Your cornea must be unclouded, smooth, and healthy for good vision. If it is scarred, inflamed, or damaged, light is not focused properly into the eye. As a result, your vision is fuzzy or you see glare.
If your cornea can’t be healed or repaired, your ophthalmologist may suggest a corneal transplant. This is where the diseased cornea is replaced with a healthy and clear cornea from a human donor.
A human donor is a person who chooses to donate (give) his or her corneas after they die to people who need them. All donated corneas are carefully examed to make sure they are healthy and safe to use.
Full-thickness corneal transplant
Your whole cornea may need to be replaced if both the front and inner corneal layers are injured. This is known as penetrating keratoplasty (PK), or full thickness cornea transplant. Your diseased or damaged cornea is removed. Next, the clear donor cornea is sewn into place.
Penetrating Keratopasty (PK) has a longer recovery time than other kinds of cornea transplants. Getting complete vision back after PK can take up to 1 year or longer.
With a PK, there is a slightly higher risk than with other types of corneal transplants that the cornea will be rejected. Meaning that the body’s immune system is attacking the new cornea tissue.
Partial thickness corneal transplant
Sometimes the front and middle layers of the cornea are injured. In this case, only those layers are removed. The endothelial layer, or the slim back layer, is kept in place. This type of transplant is called a deep anterior lamellar keratoplasty (DALK) or partial thickness corneal transplant. DALK is commonly used to treat keratoconus or bulging of the cornea.
Healing time after DALK is shorter than after a full cornea transplant. There are also fewer chances of having the new cornea rejected.
Endothelial Keratoplasty
In some eye conditions, the innermost layer of the cornea called the “endothelium” is injured. This causes the cornea to become inflamed, affecting your vision. Endothelial keratoplasty is a type of surgery that replaces this layer of the cornea with healthy donor tissue. It’s best known as a partial transplant since only this inner layer of tissue is replaced.
There are a few types of endothelial keratoplasty. They are known as:
- DSEK (or DSAEK)
- DMEK
These remove damaged cells from an inner layer of the cornea called Descemet’s membrane. The damaged corneal layer is taken out through a small incision. Then the new tissue is put in place. Just a few stitches—if any—are needed to close the incision. Much of the cornea is left untouched. This lowers the chances of having the new cornea cells being rejected after surgery.
Diseased tissue is removed
Healthy donor tissue is put in place
Some things to know:
- With DSEK/DSAEK surgery, the donor tissue can be very easy to transplant and position because it is thicker than the donor tissue
in DMEK surgery.
- In DMEK surgery, the donor tissue is thin and can be not as easy to transplant. But recovery is quicker because the transplanted tissue is thinner.
- Your eye surgeon will pick the kind of surgery based on your cornea’s condition.
What you can expect when you get a corneal transplant
Days or weeks before your transplant. Your ophthalmologist will speak with you about corneal transplant surgery. You will discuss the reasons behind why you need this surgery, how it can help your vision, and what you can expect during and after the procedure.
Once you made the decision to have a corneal transplant, a day and time will be chosen for surgery. That date could possibly change if a good donor cornea is not ready for you at that time.
Let your ophthalmologist know about all the medications you take. He or she will let you know if you can keep taking them before surgery. You may have to stop using blood thinners before the surgery.
You may have to visit your primary care doctor for a physical exam or for other tests. This will make sure that you are healthy enough to have the transplant surgery.
You will not be able to drive a vehicle after the transplant procedure. You should make appropriate arrangements for someone to drive you home after the procedure.
The day of your transplant. A cornea transplant is considered an outpatient procedure.
Here is what will happen just before and during cornea transplant surgery.
- Eye drops will be placed into your eye or eyes. You may be given other medications to help you relax.
- Your eye surgeon will choose to use either local or general anesthesia so that you do not feel pain. Next, he or she will place a device on your eye to keep it open. Even though your eye is open, you will see little to nothing because of the anesthesia.
- Your eye surgeon will have picked how to transplant the healthy donor cornea based on your specific case.
- In some cases, he or she may take out a circular part of your cornea and replace it with the same portion of the donor cornea, stitching it into place.
- Sometimes he or she will take out only a very thin layer of cells from the front of the cornea, replacing the layer with donor tissue and stitching it into place.
- In other cases, only the injured inner layer of the cornea is removed and a thin disc of healthy donor tissue is placed onto the back surface of the cornea. An air bubble is then placed into the eye to push this new cell layer into place so the cornea can heal correctly.
- Sometimes your ophthalmologist may correct other eye problems during the same surgery, such as cataracts.
- After surgery, your ophthalmologist usually tapes a shield over your eye to keep it safely covered. You will be monitored after surgery to make sure you recover from the anesthesia and can safely go home.
- Your ophthalmologist will go over what to do to care for yourself at home after surgery.
After your transplant. The day after your corneal transplant procedure, you will need to go back to your ophthalmologist’s office to have your eyes examined.
The stitches from the procedure may or may not need to be removed. This will depend on how quickly you heal, the healthiness of your eye, and the kind of stitches used.
As you recover from surgery, there are certain things that are necessary to do to care for your eye:
- Place the eye drops in your eye exactly as the ophthalmologist prescribed.
- Do not put pressure on or rub your eye.
- If needed, take over-the-counter pain medicine. Ask your doctor which ones you can take.
- Wear eyeglasses or some type of eye shield to protect your eyes.
- Speak with your ophthalmologist about when you can get back to doing your usual daily routine.
Contact your ophthalmologist if you have any concerns or questions about how to take care of yourself at home.
Depending on the kind of transplant you had and how your eye are healing, it can take up to a year or more to fully recover from this operation.
Possible problems with a corneal transplant
Organ rejection is when the body’s immune system sees transplanted tissue as something that shouldn’t be there and tries to get rid of it. Rejection is an issue for up to 3 out of 10 people who have a corneal transplant.
Warning signs that your body is trying to reject your cornea transplant include:
- eye pain
- being extra sensitive to light
- redness of the eye
- cloudy or hazy vision
Tell your ophthalmologist right away if you have any of these signs. He or she might be able to stop the rejection with medicine.
Sometimes corneal transplant can cause other eye issues such as:
- infection
- bleeding
- detached retina (when the tissue lining the back of the eye is pulled away from the eye)
- glaucoma (increased pressure inside the eye)
Even when corneal transplants work as they are supposed to, other eye problems could restrict the quality of your vision. For example, the new cornea may not be curved regularly (called astigmatism). Or you could have some type of eye disease such as macular degeneration, glaucoma, or diabetic retinopathy.
Some people may need multiple corneal transplants. The first transplant could be rejected, or other issues might occur. However, a repeat transplant has a higher rate of rejection than the first one.
Summary
Corneal transplant is a procedure that replaces a damaged or diseased cornea with a healthy donor cornea.
There are different types of corneal transplants. In some cases, only some layers of the cornea are replaced with new tissue. Sometimes, the entire cornea must be replaced. Recovering clear vision may take about a year or more after surgery.
There is a chance that the transplanted cornea might be rejected by the body. Sometimes another cornea transplant may be needed.
If you have any concerns about your eyes or your vision, speak with your ophthalmologist. He or she is committed to protecting your sight.
