During a cornea transplant, an ophthalmologist removes a portion of your cornea and replaces it with a new section of cornea from a donor. The procedure is also called a corneal transplant or a keratoplasty. About 40,000 cornea transplants are performed in the U.S. every year.
Your cornea is a clear tissue that covers the front of each eye. Light entering your eye first passes through the cornea, then your pupil (the dark spot at the center of the colored iris), and then your lens.
The cornea must remain clear for you to see properly. However, a number of problems can damage the cornea, affecting your vision. These include:
- Corneal scarring from trauma and infection.
- A degenerative condition in which the cornea becomes thin and misshapen also known as Keratoconus.
- Inherited corneal conditions (dystrophies) like Fuchs’ dystrophy, Lattice dystrophy, and others.
You may need a cornea transplant if your cornea no longer lets light enter your eye properly because of scarring or disease.
Types of Cornea Transplants
The cornea contains five layers. Cornea transplants don’t always transfer all the layers. Types of cornea transplants include:
Penetrating (full thickness) cornea transplant. If the entire thickness of the cornea is unhealthy, a full thickness corneal transplant may be required. This is called a penetrating keratoplasty (PK). Where the DSAEK and DMEK procedures focus on transplanting only the endothelial cell layer of tissue, during a PK procedure a perfectly round circle of cornea is removed from the patient and replaced with donor tissue. This new cornea is sutured into place with a stitch that is thinner than a human hair, for a comfortable healing process.
Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK)
A very common cause of a cloudy cornea is a damaged inside, or endothelial, layer of the cornea. The endothelial layer is one cell layer thick and can be damaged by surgery or trauma or the cells can die too quickly over time (a condition known as Fuchs’ Dystrophy). When there are not enough endothelial cells, water can build in the cornea causing cloudy vision and vision loss. DSAEK is a highly refined technique that replaces just the endothelial layer of the cornea, allowing surgeons to target the specific cause of the patient’s vision loss. In the DSAEK procedure the damaged cells are stripped from the patient’s eye and replaced with a very thin back portion of a donor cornea. This procedure allows your surgeon to literally replace only the damaged area of cornea, allowing a more precise treatment and better overall results. Your surgeon uses an air bubble technique to hold the new tissue in place in the eye for the entire day of surgery so that no sutures are needed.
Descemet membrane endothelial keratoplasty (DMEK) is a new type of partial-thickness corneal graft in which only the innermost corneal layers are replaced, rather than the whole thickness of the cornea, as happens in a conventional full-thickness graft (i.e., penetrating keratoplasty [PK]). In this latest iteration of endothelial keratoplasty, DMEK replaces only the Descemet’s membrane and endothelium, and leaves the patient’s cornea closer to its original condition than other transplant procedures. DMEK offers improved optical quality, fast and often complete visual rehabilitation, fast stabilization of refraction, and small refractive shift.
Lamellar Keratoplasty (LK), Deep Anterior Lamellar Keratoplasty (DALK)
At times, the front portion of the cornea can be damaged while the endothelium is healthy. In ideal circumstances, only the diseased anterior portion of the cornea will be transplanted through either a Lamellar Keratoplasty (LK) or Deep Anterior Lamella Keratoplasty (DALK) procedure. The risks and follow up care are similar to a PK. This alternative is a solution in special situations.
Success Rates of Cornea Transplants
Experts know more about the long-term success rates of penetrating cornea transplants, which use all the layers of the cornea.
Success rates are also affected by the problem that needed to be fixed with the transplant. For example, research has found that the new cornea lasts for at least 10 years in:
- 89% of people with keratoconus
- 73% of people with Fuchs’ dystrophy
- 60% to 70% of people with corneal scarring