The cornea is the clear window over the colored part of your eye (iris). When the cornea is diseased, it may lose its clarity or shape, which can then cause blurred vision. Some conditions are best treated with a corneal transplant where the abnormal or diseased cornea is replaced with healthy tissue from a donor.
Your doctor will inform you of which type of surgery may be best for you depending on which area or layer of your cornea is affected.
Corneal transplants are performed on an outpatient basis either under sedation and local anesthesia or under general anesthesia.
Partial Thickness Corneal Transplant (DSAEK)
The cornea is comprised of 5 layers – the innermost layer (on the inside of the eye) is called the endothelium. The endothelium is a layer of cells that has a very important function of “pumping” the natural fluid out of the cornea and keeping it clear. If these pump cells are not functioning properly in the cornea, the cornea swells with fluid and loses its clarity like a foggy window. If this is the only portion of your cornea that is diseased, then you may be a candidate for a partial transplant (DSAEK) where the endothelium is replaced with healthy pump cells from a donor.
DSAEK (which stands for Descemet's stripping and automated endothelial keratoplasty) replaces only the diseased pump cells, leaving the rest of your cornea intact. This allows the procedure to be performed through a much smaller incision with shorter recovery times and fewer risks than a traditional corneal transplant. It is one of the latest techniques in corneal transplantation.
During the procedure, the surgeon removes the inner layer of diseased endothelial cells. The donor tissue is carefully folded and inserted into the eye. The surgeon injects an air bubble underneath the donor tissue. The air bubble pushes the donor tissue in place, and then the natural pumping function of the endothelial cells allow the donor tissue to adhere to the patient’s cornea.
Eventually the cornea clears as the new endothelial pump cells work to pump out the excess fluid from the swollen cornea.
After surgery, it is important that you remain flat on your back as much as possible for the first 48 hours. This gives the air bubble sufficient time to allow the new donor cornea to attach properly.
Full Thickness Corneal Transplant (Penetrating Keratoplasty)
A full thickness corneal transplant or a penetrating keratoplasty (PK) is a surgical form of corneal transplantation that removes the central section of the patient’s cornea (all layers of the cornea). A new healthy donor cornea is used for replacement. This type of transplant is indicated for those patients that have diseases or scars that affect all layers of the cornea or have corneas that are severely abnormally shaped.
The new cornea is stitched into place using very fine sutures. These stitches are usually removed gradually over the course of a year. Visual rehabilitation with glasses or contacts occurs over this time frame as well.