Corneal Transplant Surgery or Keratoplasty

Who's eligible and what should you expect?

Extreme close up of human eye
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The cornea is the clear front part of the eye that covers the iris, pupil, and anterior chamber. A corneal transplant, or keratoplasty (KP), involves surgically removing the central part of the cornea and replacing it with clear and healthy corneal tissue donated by an eye bank.

If you think or have been told you need a corneal transplant, 

Who Needs a Corneal Transplant?

Good vision requires the cornea to be clear, smooth, and healthy. Light cannot focus properly inside the eye if the cornea is scarred, swollen, or damaged. The result is blurry vision or glare.

A corneal transplant may be needed if your cornea is damaged or unhealthy. Healthy corneas are obtained from eye banks after being donated by human donors. Donated corneas are thoroughly tested to ensure they are safe and healthy to use.

The National Eye Institute estimates that about 40,000 corneal transplants are performed each year in the United States. They are needed for several eye conditions, including the following:

  • Keratoconus: Keratoconus is a condition in which the normally round cornea becomes thin and develops a cone-like bulge.
  • Corneal clouding: Many conditions may cause the cornea to become swollen and cloudy, such as Fuchs’ dystrophy and pseudophakic bullous keratopathy. In severe cases, the cornea may develop small, painful blisters on the surface.
  • Corneal infection: Infections of the cornea may be bacterial, fungal, or viral. Severe corneal infections may cause scarring, thinning, or perforation of the cornea. (Herpes simplex is a common viral infection that may lead to scarring.)
  • Corneal dystrophy: Some hereditary conditions (dystrophies) can cause the cornea to become opaque or irregular.
  • Corneal injury: Injuries to the cornea may cause corneal scarring that can affect the vision

Your ophthalmologist will look at your condition carefully to assess your need for a corneal transplant. 

Types of Corneal Transplants

Three types of corneal transplants are used today. Your ophthalmologist will determine which procedure is most suitable for you based on your condition.

Full-Thickness Corneal Transplant

If both the front and inner corneal layers are damaged, your entire cornea may need to be replaced. Also known as penetrating keratoplasty (PK), full thickness cornea transplant involves replacing the full thickness of the diseased or damaged cornea with a clear donor cornea.

PK has a longer recovery period compared to other types of cornea transplants. It may take up to a year or longer for the complete vision to be restored. PK carries a slightly higher risk than other types of corneal transplants that the donor cornea will be rejected. Rejection sometimes occurs as the body’s immune system attacks the new corneal tissue.

Partial-Thickness Corneal Transplant

Sometimes the front and middle layers of the cornea are damaged and only those layers need to be removed. The endothelial layer (the thin back layer) is kept in place. This transplant is referred to as deep anterior lamellar keratoplasty (DALK) or partial thickness corneal transplant.

DALK is commonly used to treat keratoconus or bulging of the cornea. Recovery time after DALK is shorter than after a full cornea transplant. Rejection of the new cornea is also less of a risk than a full thickness corneal transplant.

Endothelial Keratoplasty

In some eye conditions, the innermost layer of the cornea (endothelium) is damaged. The damage causes the cornea to swell, affecting your vision.Endothelial keratoplasty is a surgery that replaces this layer of the cornea with healthy donor tissue. It is known as a partial transplant, as only the inner layer of tissue is replaced.

There are two types of endothelial keratoplasty: DSEK (or DSAEK) and DMEK. Endothelial transplants are used to treat conditions affecting mostly the back layer of the cornea such as Fuchs dystrophy and bullous keratopathy. It avoids a large surgical wound, minimizes visual distortion from astigmatism, and provides a more rapid visual recovery than penetrating keratoplasty for certain conditions.

Each type removes damaged cells from an inner layer of the cornea called Descemet’s membrane. The damaged corneal layer is removed through a small incision, then the new tissue is put in place, sometimes using a few stitches. Most of the cornea is left untouched, lowering the risk of rejection of the new cornea after surgery.

Before the Surgery

Once you decide to have a corneal transplant, your ophthalmologist will spend some time with you to plan the entire procedure. A  date will be chosen for surgery, but be aware that the date may change if a good donor cornea is not available on that date.

Your ophthalmologist will need to know about any medication you take, including both prescription and non-prescription. You may need to temporarily stop taking the medication before the surgery.

You will also be encouraged to make an appointment with your primary care doctor. You will be asked to undergo routine laboratory tests such as a blood count and an EKG to make sure you are healthy enough to undergo surgery. Your doctor will examine your eyes and conduct special tests to make sure your eye is ready for surgery.

Keep in mind that you will not be able to drive after the transplant surgery. You should make arrangements for someone to drive you home after surgery.

During the Surgery

Either local or general anesthesia may be used in most cases. Your doctor will discuss with you what type of anesthesia is best for you. Once you enter the operating room, your eyelids will be cleansed and covered with a sterile drape. Oxygen will be given to you by a plastic tube placed near your nose. The surgeon will then place a microscope over your eye.

During a full-thickness penetrating keratoplasty procedure, a circular instrument called a trephine is used to remove the center of the cornea. A button of donor corneal tissue is also cut to fit. The donor tissue is sewn into place with fine sutures.

Alternatively, many surgeons are now using a femtosecond laser to cut a patient’s cornea and donor tissue. The laser allows the tissue to be cut in zig-zag patterns and at controlled depths for maximum precision. This allows the incision of the patient’s tissue and the donor cornea to fit together like a puzzle piece.

With traditional transplants performed with a trephine, it could take from six to twelve months to stabilize and to obtain better vision. However, with the femtosecond laser, the precise incision heals faster, allowing more rapid suture removal and better vision.

In the EK or endothelial keratoplasty procedure, only the back layer of the cornea is replaced. The patient tends to heal much faster with this procedure, as the entire cornea is not being replaced. After the procedure is complete, an eye shield will be applied to protect the eye. You will then be taken to a recovery room to rest before being discharged.

After the Surgery

The eye is usually patched anywhere from one to three days. Your eye doctor will usually see you the very next day and remove the eye patch. He or she will examine the surgery to monitor healing and watch for rejection of the tissue, using the acronym RSVP as a guide:

  • Redness - Sudden eye redness is a sign of rejection.
  • Sensitivity - A rejection often causes significant light sensitivity.
  • Vision - A rejection can cause blurry, foggy or cloudy vision.
  • Pain - A sudden increase in eye pain or foreign body sensation can be a sign of a rejection.

After the first or second day after surgery, you may return to normal activities such as brushing your teeth, bathing, bending over, reading, walking or watching TV. Using your eye will not hurt your eye or affect healing, but should avoid any rigorous sports or rough contact with the face or the eye. It may be recommended to continue wearing an eye shield for the first week or two after surgery just to protect your eye at night while you sleep.

You must be very diligent about instilling your eye drops just as the doctor prescribes. One of the most important components of your post-operative care is to keep all your doctor’s appointments. Your doctor will need to know if the tissue begins to be rejected. One out of every four transplant recipients experiences a graft rejection. If caught early, however, it can usually be reversed with medication.

After a few months, the cornea will be stable enough to be measured for new eyeglasses. In some cases, astigmatism or nearsightedness may develop, but eyeglasses can easily correct the problem.  In other cases, a special contact lens may be needed to cover any distortion remaining on the cornea.

A Word From Verywell

Facing the fact that you need a corneal transplant may be difficult. A corneal transplant is major eye surgery and you are right to be concerned about it. However, with today’s technology, most people who undergo a corneal transplant experience a relatively uneventful process. Learning more about what is involved in a corneal transplant will put most of your concerns at ease.

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Article Sources

  • Boyd, Kierstan. About Corneal Transplantation. American Academy of Ophthalmology. Sep 2017.