If you have a condition that has affected your cornea (the normally clear front part of your eye) and the vision is affected your doctor may determine that you need a corneal transplant. This involves having surgery to replace your cornea with a cornea that has been donated by someone who has died. The cornea you will receive is referred to as the donor cornea. The donor cornea to be used for your transplant will be provided by a licensed and certified Eye Bank. The good news is that there is enough awareness about organ donation and typically there is a donor available for the restoration of your sight. Because the cornea does not have a direct blood supply, you do not have to be matched to your donor. This is also advantageous that you do not have to suppress your body’s entire immune system with pills. You will however, need to suppress the eye’s immune system with steroid drops. You will likely be on a steroid drop for the rest of your life after your transplant.
The cornea is the normal clear window over the colored part of your eye (iris). When the cornea is diseased, it loses its clarity or shape, and compromises your vision. A variety of conditions can lead to needing a transplant. Traditional corneal transplants are full thickness – or remove the entire cornea. Some patients are candidates for a partial thickness transplant. Your doctor will inform you of their opinion.
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” fluid out of the cornea and keeping its clarity. If this layer of cells is not functioning properly then the cornea swells and loses its clarity. If this is the only portion of your cornea that is diseased, then you may be a candidate for a partial transplant (DSAEK).
Both types of surgery are performed on an outpatient basis either under sedation and local anesthesia or under general anesthesia.
Partial Thickness Cornea Transplant (DSAEK)
There are several different corneal transplant procedures available to help restore vision in patients with corneal problems. The traditional corneal transplant procedure involves replacing the entire damaged cornea with a healthy one from a human donor, which is usually obtained from an eye bank. However, technological advances have allowed for the development of specialized procedures that replace only the damaged part of the cornea, while leaving the healthy parts intact.
Short for Descemet's stripping and automated endothelial keratoplasty, DSAEK replaces only the innermost layers of cells within the cornea, known as the endothelium. 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 cut specially to replace these cells and sized appropriately for your eye. The donor tissue is carefully folded and inserted into the eye. The donor tissue is then positioned inside the eye and then the surgeon injects an air bubble underneath the cornea. It is this air bubble that allows for adherence of the new transplant. A few stitches are placed to close the incision. These are buried and do not usually ever need to be removed.
After surgery, it is important that you remain positioned supine (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 Cornea Transplant (Penetrating Keratoplasty)
A full thickness cornea transplant also know as a penetrating keratoplasty is a surgical form of corneal transplantation that removes the entire (all layers of the cornea) and a new 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 and the stitches are usually removed after a year. It may take this long for vision to be restored to satisfactory levels as well, requiring many patients to wear glasses or contact lenses after this procedure, but may be the only option to restore vision in severe corneal disease.
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