Corneal Transplant (Penetrating Keratoplasty)

The cornea is a clear front dome that covers the iris and pupil. One of its functions is to allow light to enter the eye and for that it must be fully transparent. If something impairs its transparency permanently, such as scarring from an injury, an infection, or an ulcer, some of the incoming light is blocked and vision is impaired.

The cornea’s surface layer, the epithelium, is continually replacing itself with new cells. This is part of another corneal function—protecting the eye from dust and foreign particles. The old cells along with any debris are washed away by the tears as they flow across the sclera (white part) and cornea, and then into a drainage system.

This continual cell replacement means that the corneal surface can heal itself fairly quickly if there is surface damage. When damage is deeper into the cornea, it will create symptoms such as:

Blurriness
Pain
Increased sensitivity to light
Redness
Excess tears

For information about corneal infections, please see our pages on Uveitis and Keratitis. Damage may also arise from any of the corneal dystrophies such as Fuch’s Dystrophy.

When the corneal damage is permanent and interferes with clear vision, the cornea can be replaced in a corneal transplant surgery. Donated human corneas are stored in an eye bank until they are needed. In some situations, a synthetic cornea is used.

Corneal Transplant Surgery

Corneal transplant surgery is also known as corneal grafting and Penetrating Keratoplasty (PK). It replaces the full thickness of the cornea (five layers) and is usually done as an outpatient procedure. Local anesthetic is used and a sedative to help you relax.

A circular cutting device called a trephine is used to make a disc on the cornea about eight millimeters in diameter;
Your eye surgeon then cuts a circular “button”, a graft, from the donor cornea;
Using forceps, he or she positions it precisely over the open disc area and stitches it in place. The sutures are thinner than a human hair.

The procedure takes between one and two hours and at the end your surgeon will place a plastic shield over the eye for protection.

Recovery From a Corneal Transplant Surgery

At first you will have some blurred vision from swelling on the cornea. This will resolve soon and if your job does not pose any danger of eye injury, you can probably return to work in about a week. You will have steroid eyedrops to help your body to accept the new cornea. Rejection is rare because the cornea has no blood vessels.

The sutures will be removed anywhere from three to 17 months after your procedure. During the first three months, your vision will change and fluctuate. After it has stabilized and perhaps also after the stitches are removed, you can be tested for new glasses or contact lenses.

Vision improvement continues for about a year. However, because the new corneal tissue cannot exactly match the curvature of your own remaining corneal tissue, you will probably have some astigmatism and perhaps nearsightedness. Rigid gas permeable (RGP) contact lenses are often the best choice for vision correction, as they help with corneal irregularity.

When your healing is fully complete you may be able to have LASIK or PRK to reduce your dependence on eyewear.

This type of full-thickness corneal transplant is not always necessary. In some cases, just one layer needs to be transplanted. Please see our page on DSEK Surgery.

Find out what a Keratoprosthesis is.

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