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CORNEA
TRANSPLANT
TRANSPLANT SURGERY…WHAT TO EXPECT Although only 20-25% of those with keratoconus ultimately require corneal transplant surgery, for those who do, it is a crucial and sometimes frightening decision. However, those who know what to expect before, during and after surgery are better prepared and feel more in control of their health care. In keratoconus, a corneal transplant is warranted when the cornea becomes dangerously thin or when sufficient visual acuity to meet the individual’s needs can no longer be achieved by contact lenses due to steepening of the cornea, scaring or lens intolerance. Lens intolerance occurs when the steepened, irregular cornea can no longer be fitted with a contact lens, or the patient cannot tolerate the lens. Once the decision has been made, you will be less anxious and feel more in control if you know what to expect – what the “normal” routine is for this type of surgery. The more information you have, the more prepared you will be. It is a good idea to check with your insurance company prior to scheduling your surgery to check your coverage and any pre-authorization requirements. Ask exactly what will be covered and what will not. Ask especially about your post operative office visits, glasses and/or contact lenses. A few days prior to surgery a general medical examination and routine laboratory tests (such as blood count and EKG) are done to insure that you are well enough to undergo surgery. You should not use aspirin for 2 weeks prior to surgery, since it tends to cause bleeding during surgery. Antibiotic drops are generally started one day before surgery to protect the eye from infection. Do not eat or drink anything after midnight before the surgery (ask your doctor about taking prescription medications the day of the surgery). In most cases, the surgery is done on an outpatient basis- you enter the hospital or surgery center a few hours prior to surgery and leave that same day- generally a few hours after the surgery. In the “pre-op” waiting area, you will be “prepped”- medication will be given to help you relax before surgery. A needle attached to tubing will be inserted to deliver fluids and medications into your vein and EKG leads will be attached to your chest in order to monitor your heart. These are standard safety precautions. Local or general anesthesia can be used for this procedure. The decision as to which type is used should be discussed with your surgeon preoperatively and is based on your age, general health, length of surgery, and your doctor’s preference and your anxiety level. In the operating room, your eyelids are carefully washed and covered with a sterile plastic drape. Oxygen is occasionally provided by a plastic tube placed near the nose. Patients often doze off during the operation, and most are left with vague recollections of a short procedure, although some remember all of it. The entire procedure is done under a microscope. A circular cookie cutter-like instrument, called a trephine, is used to remove the center of the diseased cornea. A "button" of similar size is cut from the donor cornea. This donor tissue is then sewn in place with extremely fine nylon sutures. At the conclusion of the procedure, a patch and shield are applied to protect the eye. You will then be taken to the recovery room to wait until you are fully awake before being discharged. After surgery, you should rest the remainder of the day. Post surgical pain varies from person to person. Typically there is either no pain or only slight soreness for a few days which is usually relieved by Tylenol. Discuss pain management with your surgeon before the surgery and fill prescriptions to have available if needed afterwards. The
operated eye is patched until the surface epithelium (top layer of the
cornea) is healed, usually 1 to 4 days. Do not remove the patch.
The doctor will see you the day after surgery, remove the patch and determine
if it needs to be worn longer. You will also receive detailed instructions
at this visit. It’s a good idea to bring someone with you- two pair
of ears are better than one! Be sure you really understand the instructions,
ask questions if something is unclear.
After the patch is removed, it is important to protect the eye from accidental bumps or pokes. Typically, for several months after surgery, patients wear glasses during the day and a metal or plastic shield at night to protect the eye from trauma while sleeping. Since the new cornea is delicately sutured in place, a direct blow to the eye must be avoided. Contact sports are discouraged after corneal transplant. Otherwise, normal activity can be resumed within a few days. After the first day, shaving, brushing teeth, bathing, light housework, bending over, walking, reading, and watching TV will not hurt the eye. Because the cornea has no blood supply, the transplant heals relatively slowly. Sutures are left in place for three months to one year, and in some cases if the vision is good, they are left in permanently. The sutures are buried and therefore don't cause discomfort. Occasionally, they do break and then need to be removed. Often they are removed, adjusted or loosened to improve vision. Suture adjustment and removal are simple, painless office procedures. The sutures used in corneal transplants are made of a monofilament nylon and are quite small (22 microns - 1/3 the thickness of a human hair). There are many different suturing patterns used by surgeons the world over. All of these suture techniques are effective. Some are utilized because of the surgeon’s preference and training. Other suturing techniques are employed depending on the specific problem for which the transplant is being done. In some cases, surgeons will use 16 individual ("interrupted") sutures; others use a continuous ("running") suture, which is much like a hemstitch. Still others routinely use a combination of both types. In all cases, the results are more or less equivalent. Vision gradually improves as the new cornea heals. There is often useful vision within a few weeks. However, in some cases, it may take several months to a year for full vision to develop. To prevent rejection of the new cornea, steroid eye drops are used for several months after surgery. In some cases, low dosage steroid drops are continued indefinitely. Unlike oral steroids, steroid eye drops cause no side effects elsewhere in the body. Occasionally other eye medications are necessary. It is important to call immediately (including weekends, evenings, and holidays) if you notice any unusual symptoms, including Redness, Sensitivity to lights, Vision loss, or Pain ("RSVP"). Flashing lights, floaters, and loss of peripheral vision should also be reported immediately. Postoperative care is extremely important and by far the most time-consuming part of having a corneal transplant. The eye is checked the day after surgery, several times in the first two weeks, at gradually longer intervals over the first year, and usually yearly thereafter. There is every reason to believe your graft will succeed and last a lifetime. With proper care and prompt attention to any sign of rejection the graft will remain clear and healthy. TRANSPLANT
TERMS
Medical terminology is a language of its own. It can be confusing and alarming if you don’t know what the words mean. This will help you sort out the language of transplant surgery: Atopic or Atopy - conditions associated with allergy like: asthma, eczema, hayfever Donor tissue - the part of the cornea that is transplanted Epikeratophakia - a thin disk of donor cornea is sutured to the patient’s cornea after the patient’s epithelium (top layer) has been removed to add thickness. Filaments - string or ribbon-like threads of epithelial cells and mucous that attach to the outer surface of the cornea. Host tissue - cornea of the patient, the part of the patient’s cornea that is left in place when the central portion is removed to be replaced with the donor tissue. Hydrops – a condition in which the back surface of a thin cornea ruptures, allowing fluid to waterlog the cornea, making it opaque instead of clear. Kerato - (prefix) pertaining to the cornea Keratoplasty - (corneal transplant) is the excision of all layers of the central portion of the cornea and replacement with a clear cornea from a human donor. Penetrating Keratoplasty - (corneal transplant) full thickness layers of the cornea are replaced with a full thickness layer from a donor. The entire thickness of cornea is removed and replaced by full thickness donor corneal tissue. Keratometer - a device used to measure corneal curvature. Keratophakia - the surgical removal part of the surface of the cornea and its replacement with a donor cornea that is reshaped and transplanted to the patient’s cornea. Lamellar Keratoplasty - (Non-Penetrating Keratoplasty) the outer two thirds of the cornea is removed and replaced with donor cornea. Keratomileusis - patient’s cornea is removed, frozen, reshaped on a computer assisted lathe- then returned to it’s original position. LASIK - "laser assisted in situ keratomileusis." It is a refractive surgery procedure for the correction vision in which a thin layer of the front of the cornea is lifted surgically and the underlying cornea is reshaped using an excimer laser. It is not a procedure applicable to keratoconus. Donor Tissue - eye tissue removed upon a donor’s death for transplantation. Trephine - a surgical instrument, a cutting tool, used to make a precise circular cut in tissue. Sutures - stitches, usually of a nylon material that are used to sew the new cornea tissue in place. Graft-host junction - where the donor cornea and patient’s cornea meet and are sutured. Keratic precipitates - (KPs) inflamatory cells that adhere to the innermost layer of the cornea and signal a rejection episode. Decentration - off centered position VISION AFTER A CORNEAL TRANSPLANT Vision varies a great deal after a transplant and continues to change for many months. It may start out very poor and gradually improve or be very good immediately after surgery and then worsen. It could take up to a year to develop good, stable vision. The more severe the keratoconus is, the more likely it is to see a dramatic improvement immediately after surgery. This is due to the dramatic change that occurs when the bulging and distorted cone is replaced with a new smooth donor graft. While some patients develop good vision while the sutures are still in place, best, most stable vision usually occurs after all the sutures are removed. Suture removal occurs at different times for different patients. It depends on the rate of healing, which is faster in younger people. The majority of keratoconus patients have their sutures removed 6-12 months after surgery. An
important question is the level of uncorrected vision that can be expected
after surgery. Will glasses be an option, or will contact lenses
still be needed? A small percentage of transplant patients do obtain
uncorrected vision good enough that neither glasses nor contacts are needed
after surgery, but in the majority of cases, some form of vision
correction is needed after surgery. Although vision may not be perfect
after surgery, it is nearly always a lot better than it was before.
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