What to Expect From a Corneal Transplant

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 healthy corneal tissue from a deceased donor.

This surgery may be necessary to restore quality vision if your cornea is damaged (due to an eye injury, for instance) or impacted by an infection or another ocular (eye) condition.

Reasons for 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.

The National Eye Institute estimates that about 47,000 corneal transplants were performed in the United States in 2014. They are needed for several eye conditions, including:

• 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 painful small 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 vision.

Who Is Not a Good Candidate?

Your ophthalmologist will consider your condition carefully and assess your need for a corneal transplant. If your vision is improved by wearing glasses or contact lenses, you are unlikely to be a candidate for this procedure.

Other reasons that might preclude you from being a candidate include having pseudophakic or aphakic corneal edema, or a history of glaucoma. A 2009 study in Ophthalmology found that having either type of corneal edema (swelling) increased the risk of graft failure significantly when compared with people who had Fuchs' dystrophy (27% vs. 7%). Those who had prior glaucoma surgery with preoperative glaucoma medication use had a substantially increased graft failure rate as well.

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

Penetrating keratoplasty (PK), also called a full-thickness corneal transplant, is done when both the front and inner layers of the cornea are diseased or damaged, requiring replacement of the entire cornea.

It takes longer to recover from PK than from other types of corneal transplants, and it is possible for it to take up to a year or more after the transplant for vision to be restored completely. Furthermore, there is a slightly higher risk that the body will reject the donor cornea compared with other types of corneal transplants.

Partial-Thickness Corneal Transplant

In some cases, only the front and middle layers of the cornea need to be removed via a procedure known as deep anterior lamellar keratoplasty (DALK), or a partial-thickness corneal transplant. With this, the endothelial layer (the thin back layer) is kept in place. DALK is often used to treat keratoconus, or bulging of the cornea. 

It takes less time to recover after DALK than after PK, and the risk of rejection is lower as well.

Endothelial Keratoplasty

When the endothelium—the innermost layer of the cornea—is damaged, the cornea swells. In this case, an endothelial keratoplasty is performed; this procedure uses healthy donor tissue to replace this layer of the cornea. Endothelial transplants are used to treat conditions affecting mostly the back layer of the cornea, such as Fuchs' dystrophy and bullous keratopathy.

The two types of endothelial keratoplasty include Descemet's stripping endothelial keratoplasty (DSEK) and Descemet's membrane endothelial keratoplasty (DMEK). Both procedures remove damaged cells from Descemet’s membrane, an inner layer of the cornea, through a small incision. The new tissue is then put in place; sometimes this requires a few stitches.

These procedures can treat astigmatism, and recovery can be quicker than with penetrating keratoplasty for certain conditions. The risk of rejection of the new cornea is lessened due to the fact that most of the cornea is left untouched.

Donor Recipient Selection Process

The Eye Bank Association of America (EBAA) is able to fulfill all the demand for corneas in the United States and provide approximately 28,000 corneas for use internationally, so there is no wait involved, as there can be with some organ transplants.

Recovery of the donor eye tissue takes place within hours of death. The preservation medium used in the United States will keep the cornea’s cells alive for 14 days after recovery, but most transplants occur within a week of recovery.

Types of Donors

Healthy corneas are obtained from individuals who, before their death, gave consent for such a donation. Procured corneas are thoroughly tested to ensure they are safe and healthy to use.

Aside from those suffering from infections or a few highly communicable diseases such as HIV or hepatitis, most people are suitable cornea donors. The donor's blood type does not have to match that of the recipient, and age, eye color, and quality of vision (e.g., nearsighted, farsighted) are irrelevant.

The donated eyes and the donor’s medical and social history are evaluated by all eye banks in accordance with the EBAA's strict Medical Standards, as well as with Food and Drug Administration (FDA) regulations. The EBAA also provides standards for eye banks to use in training personnel to evaluate donor eyes; only corneas that have met strict evaluation guidelines set forth by the EBAA and FDA are distributed.

Before the Surgery

Once you decide to have a corneal transplant, your ophthalmologist will spend some time planning the entire procedure with you. The date of your surgery will depend on when an acceptable donor cornea is available.

Your ophthalmologist will need to know about any medications you take, both prescription and nonprescription. You may need to temporarily stop taking some before the surgery. If you take aspirin on a regular basis, for example, you will be asked to stop taking it two weeks before the procedure because it can cause bleeding during surgery. Your ophthalmologist will have you use antibiotic eye drops one day before the surgery to protect the eye from infection.

You will also be encouraged to make an appointment with your regular healthcare provider. You will be asked to undergo routine laboratory tests such as a complete blood count (CBC) and an electrocardiogram (EKG) to make sure you are healthy enough to undergo surgery. A healthcare provider will examine your eyes and conduct special tests to make sure your eye is ready for surgery as well.

Keep in mind that you will not be able to drive right after the transplant, so you should make arrangements for someone to drive you home after the procedure.

Surgical Process

Corneal transplants are performed on an outpatient basis.

Once you enter the operating room, your eyelids will be cleansed and covered with a sterile drape. You will be given either local anesthesia with a sedative or general anesthesia, depending on what your healthcare provider thinks is best in your case. The surgeon will put eye drops in your eye and then place a microscope over it.

During a full-thickness penetrating keratoplasty procedure, a circular instrument called a trephine is used to remove the center of the cornea. A piece of donor corneal tissue is cut to fit and then sewn into place with sutures made of a monofilament thread that is about one-third the thickness of a human hair.

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 zigzag 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.

With traditional transplants performed with a trephine, it could take from six to 12 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. Healing is usually 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 wear an eye patch after surgery and then rest in a recovery room before being discharged. You may be asked to lie on your back for a while to make sure the donor tissue stays in place.

After Surgery

You will wear an eye patch for anywhere from one to three days. To prevent rejection of the new cornea, you may be asked to use steroid eye drops for a few months after surgery; in some cases, other eye medications are necessary as well.

You must be very diligent about instilling your eye drops just as prescribed. One of the most important components of your postoperative care is to keep all your medical appointments.

Your ophthalmologist will usually see you the day after your surgery. They will examine the eye 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.

Sometimes a corneal transplant can cause other eye problems, such as:

• Infection
• Bleeding
• Detached retina (where the tissue lining the back of the eye pulls away from the eye)
• Glaucoma (through increased pressure inside the eye)

Your surgeon will give you recommendations to follow regarding resuming normal activity, such as bathing, bending over, reading, walking, or watching TV. In particular, bathing and bending over may be restricted, since bending can cause increased eye pressure, which you’ll want to avoid.

Using your eye will not hurt it or affect healing, but you should avoid any rigorous sports or rough contact with the face or the eye. In addition, avoid getting the eye wet with water, especially standing water and bathwater, to reduce the risk of infection. Your surgeon is also likely to tell you not to rub your eyes, and they may recommend you continue wearing an eye shield for the first week or two after surgery to protect your eye at night while you sleep.

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

Prognosis

Over 95% of all corneal transplant operations successfully restore the corneal recipient’s vision, according to the EBAA.

Some people, however, may need more than one corneal transplant. While the original transplant lasts a lifetime for a portion of transplant recipients, typically donor corneas last around 10 to 15 years, depending on how young or old the recipient is.

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. Learning more about what is involved in a corneal transplant can hopefully ease most of your concerns.