Published: Apr. 14, 2010
Updated: Feb. 6, 2012
The Duke Eye Center performs more than 200 cornea transplants (keratoplasties) every year, with outstanding outcomes. Our cornea specialists offer several advanced alternatives to traditional “full thickness” transplant methods that can result in better outcomes and shorter recovery times.
Newer techniques include DSEK (Descemet's stripping endothelial keratoplasty) and DALK (deep anterior lamellar keratoplasty). These methods, available for adult and pediatric patients, selectively remove only the diseased layers of the cornea while leaving intact normal areas, thereby decreasing the risk of complications encountered with full-thickness transplantation.
The cornea is the transparent covering over the front of the eye. It is like the window that you look through to see the world.
Diseases of the cornea can negatively affect vision by distorting it (keratoconus) or by making it less transparent (edema from loss of cells or scarring from a variety of causes). When this window becomes distorted or scarred it disturbs light coming into the eye causing poor vision or even blindness.
If the vision cannot be corrected using non-surgical means, it may become necessary to replace the diseased cornea for vision correction.
This is traditional full thickness conventional cornea transplant. Though it was first described over 100 years ago, improvements in instrumentation and technique have made modern PKP one of the most successful transplantations available in medicine today.
In PKP, your surgeon removes the central portion of the diseased cornea and replaces it with a clear donor cornea. The new cornea is placed in the opening and is sewn in with a very fine thread. The thread stays in until the eye heals properly. Following surgery, eye drops are used to help promote healing.
Endothelial cells line the inside/back of the cornea and are responsible for keeping the cornea clear. When they stop working, the cornea can swell with fluid, eventually losing transparency.
In DSEK, only the diseased endothelial cells (and its backing membrane – Descemet's membrane) is removed. It is then replaced with healthy endothelial tissue from a donor cornea. These healthy endothelial cells help to clear the cornea that they are transplanted onto.
DALK is the opposite of DSEK. For corneal diseases affecting the outside/front of the cornea (such as scars or distorted corneas), DALK is used to remove only the front 95 percent of the cornea, leaving the back intact. The healthy, clear front of a donor cornea replaces the removed tissue and is sewn into place.
Selective, layered corneal transplant approaches such as DALK and DSEK could eventually replace full-thickness transplants altogether. Both procedures offer faster recovery time, and because only the diseased cornea is replaced, they better retain the structural integrity of the eye. DALK in particular offers a much lower risk of rejection because the body generally does not sense the donor tissue in the outside layers of the cornea.
Current research is exploring the use of femtosecond lasers to help remove and prepare the donor tissue in such a way that the donor tissue can “dove-tail” into the patient’s own cornea, reducing the amount of suturing needed.
All patients should ask their surgeons about the full risks, benefits, and alternatives of all the different types of keratoplasties and whether they are suitable for them.
Learn more about cornea and external eye disorders: