What is a corneal transplant? Is it safe?A corneal transplant involves replacing a diseased or scarred cornea with a new one. When the cornea becomes cloudy, light cannot penetrate the eye to reach the light-sensitive retina. Poor vision or blindness may result.In traditional corneal transplant surgery, the surgeon removes the central portion of the cloudy cornea and replaces it with a clear cornea, donated through an eye bank. A trephine, an instrument like a cookie cutter, is used to remove the cloudy cornea. The surgeon places the new cornea in the opening and sews it with a very fine thread. The thread stays in for months or even years until the eye heals properly (removing the thread is quite simple and can easily be done in an ophthalmologist's office). Following surgery, eye drops to help promote healing will be needed for several months.
Corneal transplants are very common in the United States; about 40,000 are performed each year. The chances of success of this operation have risen dramatically because of technological advances, such as less irritating sutures, or threads, which are often finer than a human hair; and the surgical microscope. Corneal transplantation has restored sight to many, who a generation ago would have been blinded permanently by corneal injury, infection, or inherited corneal disease or degeneration.
Even with a fairly high success rate, some
problems can develop, such as rejection of the
new cornea. Warning signs for rejection are
decreased vision, increased redness of the eye,
increased pain, and increased sensitivity to
light. If any of these last for more than six
hours, you should immediately call your
ophthalmologist. Rejection can be successfully
treated if medication is administered at the
first sign of symptoms.
If you experience any such problems after surgery, please contact us, as we always have someone on call to examine you or can arrange for you to be seen locally.
More recent developments in corneal transplant allow safer surgery for patients with faster healing and more stable long-term results. They have their own unique advantages and disadvantages, but our doctors can tell you if you are a candidate.
In 1998, Dutch ophthalmologist Gerrit Melles, MD described a technique in which the inside layers of the cornea were manually dissected and selectively replaced (Melles et al, 1998). In 2001, Mark Terry, MD described a modified technique in which the dissection was performed with viscoelastic and termed his technique deep lamellar endothelial keratoplasty, or DLEK (Terry & Ousley 2001). The manual dissection is tedious and involves a steep learning curve. Dr. Melles has since developed a technique that involves stripping of Descemet’s membrane instead of a lamellar dissection, which has been termed Descemet’s stripping endothelial keratoplasty, or DSEK (Melles et al, 2004).
Endothelial transplantation offers several advantages including less postoperative astigmatism, faster visual recovery, and stronger wound integrity (Terry & Ousley 2001). Theoretically, there is less risk of rejection since less of the patient’s tissue is replaced. Finally, there is the potential to make more efficient use of transplant tissue—using the endothelium for DLEK, DSEK, or DSAEK in one patient and the stroma for a lamellar graft in another. It is useful in patients with varying types of endothelial dysfunction, including Fuchs Dystrophy, Pseudophakic Bullous Keratopathy (PBK), Aphakic Bullous Keratopathy (ABK), and Posterior Polymorphous Dystrophy (PPMD) (Melles et al, 1998, Terry & Ousley 2001).
Dr. Rosenwasser is experienced in both DLEK, DSEK, and DSAEK corneal transplants as well as the DALK procedure for keratoconus. Dr. Rosenwasser has done over 600 endothelial keratoplasties by the Fall of 2009
Deep anterior lamellar keratoplasty is a technique in which the front 95% of the cornea is removed, allowing patients to keep their own endothelium.
The surgery offers more safety and stability to patients during surgery. It also reduces the risk of rejection and transplant failure.
This technique takes longer to perform than a traditional transplant. It may be a good option for certain patients, for example, those with keratoconus or corneal scarring.