What is Corneal Transplant?
Corneal transplant is an outpatient surgical procedure that restores vision impaired by thinning, damage, or clouding of the cornea.
The cornea is the clear, domed part of the eye and is essential to vision because it focuses light coming into the eye into the retina. The cornea can become damaged from a variety of medical conditions including diabetes or from an injury.
Corneal transplants are performed by ophthalmologists and in most cases patients are awake and alert during the procedure. A sedative may be given to keep the patient calm during the procedure and a local anesthetic is used to numb the eye area. Corneal Transplant recipients normally go home the same day. Length of recovery depends on the type of transplant performed.
Each year organ donors give sight back to over 40,000 people according to The Eye Bank of America. The Kellogg Eye Center of the University of Michigan says that corneal transplants are the most common and most successful transplant surgery performed.
Who Gets Corneal Transplants?
Thanks to numerous eye banks and plentiful donors the wait for corneal transplants is usually short.
Individuals with impaired vision due to a damaged or diseased cornea may be considered for corneal transplant. Damage is often caused by infection or eye injury.
-Sometimes the cornea becomes scarred, swollen or permanently discolored after injury.
-Macular degenerative, diabetes and other conditions can cause keratoconus (corneal thinning). Other diseases that damage the cornea are hereditary corneal failure and corneal dystrophies.
-Fuchs’ dystrophy, an inherited disease which causes the inner layer of the eye to slowly die creating swelling and clouded eyes.
Three Transplant Techniques
There are three common techniques for corneal transplantation. In all three techniques a dime sized portion of a healthy donor eye is required. The donor’s cornea (sometimes called the window to the eye) is removed postmortem and surgically attached to the recipient’s eye to replace the damaged or diseased cornea and restore clearer vision.
Penetrating Keratoplasty (PKP)
A.k.a.Full-thickness corneal transplant. PKP is the oldest and most invasive of the three approaches. PKP replaces the entire corneal area. This is a relatively safe procedure that has been common in America for many years. This technique is recommended for significant damage when all of most of the cornea is dead.
The disadvantage to this technique is that since the entire cornea (the full thickness) is replaced and several sutures are used recovery time is longer than DSAEK and DEK surgeries.
Descemet Stripping Endothelial Keratoplasty (DSAEK)
DSEAK is called a sutureless transplant and is frequently recommended to treat corneal swelling. Unlike PKP this approach leaves most of the cornea undisturbed and replaces only the endothelial layer. Instead of replacing the cornea DSAEK grafts a portion of a donor cornea onto the existing cornea.
A single small incision is made to place the graft requiring only one suture. Advantages to this less invasive procedure are faster recovery and a stronger eye with less risk of astigmatism post surgery. Disadvantage to DSAEK is that it doesn’t correct vision in scarred or irregularly shaped corneas.
Deep Anterior Lamellar Keratoplasty (DALK)
DALK is more invasive than DSAEK but less aggressive than PKP. DALK offers patients with corneal scarring or keratoconus a less aggressive option than PKP. DALK leaves the endothelium (the thin inner layer of the cornea) intact replacing the rest of the cornea.
Since DALK does not disturbing this thin inner layer of the cornea transplant recipients are less likely to reject the donor tissue of the new cornea. This is a good option for individuals with higher risk of organ rejection and provides an opportunity for donated tissue that is not suitable for PKP transplants due to disease of injury to the endothelial layer.
Which Procedure Is Right For Me?
The best way to choose a corneal transplant technique is to find an ophthalmologist that you are comfortable with, listen to their recommendations and be sure you understand the procedure.
-Be sure you understand what is causing your vision problem. Is your cornea diseased or damaged and why?
-Have a general checkup with your primary physical and be sure to tell them which procedure has been recommended. Think of this like a second opinion about your health and a screening for potential risk factors.
-Be able to describe the procedure your ophthalmologist has recommended. Explaining something is the best way to check your own understanding.
-Know what to expect after the surgery. How long will it take for you to recover? What are the possible complications? How much of your vision should the procedure restore and how long should the improvement last?
Corneal Transplant-University of Michigan Kellogg Eye Center, Kellogg Eye Center
Cornea Donation and Transplant Statistics, Eye Bank Association of America
Paul B. Griggs, MD, Corneal Transplant, Medicine Plus Medical Encylopedia
Paul B. Griggs, MD, Corneal Transplant, UCLA System Health Resources