At the Rand Eye Institute, Since DSEK (Descemet’s Stripping Endothelial Keratoplasty) became available, Corneal Transplants are seldom needed
Imagine replacing a corneal transplant operation with a 20 minute outpatient procedure that does not require stitches or local anesthetic injections. Well, this is now possible for many people. Instead of removing the whole thickness of the cornea and suturing a new donor cornea into position, the eye surgeon can now replace just the inner layer of cells (endothelium) and achieve better results with diminished healing time. It’s like replacing the wallpaper instead of replacing the wall. The patient can go home right after surgery without even having to have an eye patch. Let’s look at this in more detail.
The cornea is a transparent dome on the front of the eye. The cornea is just like a watch glass; it lets the light in but prevents the fluids inside the eye from leaking out. Corneal edema (swelling) produces a loss of transparency of this normally clear tissue and frequently is the basis for decreased vision. Corneal edema is caused by a loss of a special layer of cells, the endothelium. The endothelium is a very thin layer of cells found on the inner surface of the cornea that actively pumps fluid out of the cornea in order to maintain the remarkable clarity of the cornea. These cells are not capable of dividing, replacing or repairing themselves: When we lose these cells and there are no longer enough cells to keep the cornea dehydrated, the cornea swells and becomes clouded – blurry vision ensues. The only treatment for visually significant corneal swelling is to replace these cells. In the old days, this meant replacing the whole cornea.
In the past, replacing the endothelial cells could only be done with the surgeon performing a full thickness corneal transplant. A full thickness corneal transplant requires a local anesthetic injection and the complete removal of the center of the cloudy cornea followed by replacement with a similar sized piece of clear corneal tissue from a donor cornea. The edge between the new cornea and old cornea takes almost a year to heal so the new cornea must be sutured in place with very fine stitches to maintain strength and stability of the transplanted tissue. After the operation, it usually takes 3 to 6 months and sometimes longer to obtain your best vision.
After surgery, glasses or contact lenses are commonly required. As the stitches loosen or are removed, the curvature of the cornea may change requiring a number of changes in your glasses. After a year, an additional procedure, a laser vision correction can be performed to reduce the astigmatism and the dependence on eyeglasses.
The corneal transplant is a wonderful procedure and has restored eyesight to millions. The results of corneal transplantation are excellent, but as you can see, it takes a long time to heal. That is why it is such a wonderful thing to be able to replace full thickness corneal transplantation with the new partial thickness DSEK procedure. This is now an option for many who would otherwise necessitated a full thickness transplant.
DSEK is safer because all of the work is done through a microscopically small incision instead of a large one and very few restrictions are necessary after surgery.
In the DSEK procedure, only the thin layer of donor corneal tissue containing the endothelial cells is transplanted. This is a very delicate procedure, but when this paper thin layer is placed just right, on the underside of the recipient’s cornea, the endothelium adheres to the back surface of the recipient’s cornea and automatically clears the cornea within days instead of months.
Although DSEK is one of the most sophisticated and precise microsurgical procedures performed by an eye surgeon, as far as the patient is concerned, a big procedure has now been replaced by a much simpler, outpatient procedure that allows you to return to normal activities and restores your vision sooner.