Keratoplasty Surgery: Surgeries

Keratoconus Eye Disease

What is keratoplasty or corneal transplantation?
In corneal transplant, also known as keratoplasty, a patient’s damaged cornea is replaced by the cornea from the eye of a human cadaver. This is the most common type of human transplant surgery and has the highest success rate. Eye banks acquire and store eyes from donors to supply the need for transplant corneas.

When keratoplasty is needed?
Corneal transplant is used when vision is lost because the cornea has been damaged by disease or traumatic injury, and there are no other viable options. Some of the conditions that might require corneal transplant include the bulging outward of the cornea (keratoconus), a malfunction of the cornea’s inner layer (Fuchs’ dystrophy), and painful corneal swelling (pseudophakic bullous keratopathy).

Other conditions that might make a corneal transplant necessary are tissue growth on the cornea and Stevens-Johnson syndrome, a skin disorder that can affect the eyes. Some of these conditions cause cloudiness of the cornea; others alter its natural curvature, which also can reduce vision quality. Injury to the cornea can occur because of chemical burns, mechanical trauma, or infection by viruses, bacteria, fungi, or protozoa.

The herpes virus produces one of the more common infections leading to corneal transplant. Corneal transplants are used only when damage to the cornea is too severe to be treated with corrective lenses. Occasionally, corneal transplant is combined with other eye surgery such as cataract surgery to solve multiple eye problems with one procedure.

Keratoplasty Description:PK method
The cornea is the transparent layer of tissue at the front of the eye. It is composed almost entirely of a special type of collagen. It normally contains no blood vessels, but because it contains nerve endings, cornea damage can be very painful. Over 90% of all corneal transplants in the world are penetrating keratoplasty (PK method).

Who performs the procedure and where is it performed?
Corneal transplants are performed by an ophthalmologist, who is a corneal specialist and is expert at transplants and corneal diseases. Patients might be referred to a corneal specialist by their ophthalmologist or optometrist. Surgery is performed in a hospital setting, usually on an outpatient basis. Some surgeons may also perform the procedure at an ambulatory surgery center designed for outpatient procedures.

Description:
Surgeons may discuss the need for corneal transplants after other viable options to remedy corneal trauma or disease have been discussed. No special preparation for corneal transplant is needed. Some ophthalmologists may request that the patient have a complete physical examination before surgery. Any active eye infection or eye inflammation usually needs to be brought under control before surgery.

In a corneal transplant, a disc of tissue is removed from the center of the eye and replaced by a corresponding disc from a donor eye. The circular incision is made using an instrument called a trephine, which resembles a cookie cutter. In one form of corneal transplant, penetrating keratoplasty, the disc removed is the entire thickness of the cornea and so is the replacement disc. The donor cornea is attached with extremely fine sutures.

Surgery is performed under general anesthesia and requires around 45 minutes.

Aftercare:
Corneal transplant is often performed on an outpatient basis, although some patients need brief hospitalization after surgery. The patient will wear an eye patch at least overnight. An eye shield or glasses must be worn to protect the eye until the surgical wound has healed. Eye drops will be prescribed for the patient to use for several weeks after surgery. Some patients require medication for at least a year. These drops include antibiotics to prevent infection as well as corticosteroids to reduce inflammation and prevent graft rejection.

For the first few days after surgery, the eye may feel scratchy and irritated. Vision will be somewhat blurry for as long as several months. Sutures are often left in place for six months, and occasionally for as long as two years. Some surgeons may prescribe rigid contact lenses to reduce corneal astigmatism that follows corneal transplant.

Patients can expect restored vision after the healing process is complete. In some patients, this might take as long as a year. Patients with keratoconus, corneal scars, early bullous keratopathy, or corneal stromal dystrophies have the highest rate of transplant success. Corneal transplants for keratoconus patients have a success rate of more than 90%.