For the past 50 years, replacing a damaged cornea with donor tissue has been the standard for patients requiring corneal transplantation. Today, corneal specialists are able to target replacement of just the diseased endothelial (inner) layer of the cornea for select patients whose inner corneal layer is not working properly and causing their cornea to become swollen. This is done through a procedure called Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK).
DSAEK begins with only a small incision on the side of the cornea. The inner layer of the cornea is removed and a donor layer is put in to place. The entire procedure takes approximately one hour.
Leaving the front surface on the cornea without sutures or incisions allows for quicker healing and recovery times, and the patient’s natural astigmatism (if any is present) is not affected by sutures that can distort the cornea. Additionally, as there are no large wounds or sutures in the front of the cornea, there is less risk for wound rupture or discomfort from broken or loose sutures.
Patients who undergo a typical corneal transplant may not see well for up to a year or so. In comparison, DSAEK patients usually recover good vision within several months or possibly weeks. The corneal shape is also more stable earlier in the post-operative period. In addition, there is at least some theoretical advantage of introducing less foreign tissue perhaps decreasing the risk of rejection.
Since the recovery period is much quicker with DSAEK, patients with two diseased corneas can be considered for treatment of the second eye much more quickly.
Final visual results are not known until after many months, and patients are asked to return to the office frequently during the first year.
Obtaining a Donor Cornea from the Eye Bank
At present, the only source of corneal tissue is from donor tissue. The transplanted corneas come from a donor who has willed his or her cornea for transplantation, or whose family has donated the cornea after the donor’s death. It may be upsetting to look upon the dying patient as a source of replacement tissue, but for most families, the opportunity to give sight to another human is comforting.
All corneas are screened for HIV and Hepatitis, as well as other infectious diseases. The waiting period is usually about four to six weeks. Surgeries are tentatively scheduled with the hospital, however there will usually (a 70-80 % chance) be a cornea available on the day of surgery. If not, patients are rescheduled soon after their original date.
Blood samples, EKG, and/or chest X-rays are required (some testing depends upon your age and health status) to clear you for surgery.
The Day Before Surgery
On the day before surgery, our office contacts patients to let them know if an appropriate donor has been found. If so, a nurse from the hospital informs patients in the late afternoon or early evening regarding what time to arrive for surgery. Patients are not allowed to eat or drink anything after midnight.
The Day of Surgery
Corneal transplant surgery is normally done on an outpatient basis and patients are at the hospital for at least 5 hours. All patients should have someone to drive them home.
A nurse interviews the patient about their general state of health and an anesthesiologist will screen you prior to surgery (most corneal transplant surgeries are performed under local anesthesia).
If local anesthesia is used, the physician will inject medication around your eye that will temporarily prevent pain and movement. It will also block your vision during surgery. Sterile drapes will be placed to isolate the eye having the surgery and adequate ventilation will be provided.
If general anesthesia (less frequent) is used, patients awaken in the recovery room and will then be moved to a room in the hospital after an hour.
To assure that your donor cornea remains secure, very fine stitches will be placed around the outer edge of your cornea with the aid of a microscope.
A patch and protective shield are placed over the operated eye when surgery is complete.
Patients stay in the hospital for at least an hour after surgery. They are able to walk to the bathroom with the assistance of the nursing personnel and may sit for meals.
Patients who had local anesthesia are able to resume their regular diet. Patients who had general anesthesia receive liquids for their first meal but are able to resume a regular diet the following day.
The Day After Surgery
The eye dressing will remain in place until the morning following the surgery when patients have their first post-operative appointment. The doctor will remove the patch and protective shield the next morning. Patients are permitted to wear glasses during the day, and a shield must be worn at night. One or the other should be worn at all times.
Eye pain following a corneal transplant is usually minimal. Antibiotic, dilating and steroid drops will be instilled to prevent infection and rejection of the donor cornea.
Post-transplant Cornea Care
Antibiotic and dilating drops will be prescribed for one month. Steroid drops may be prescribed for at least one year. Patients and their families are instructed on the proper techniques for instilling eye drops.
If you do not have enough eye medication at home, call us with the name of the medication and the phone number of your pharmacy. It is crucial that you receive every dose of your medication. Please plan ahead if your drops are running low. Avoid running out in the evening or on a weekend or holiday.
You may clean around your eye, but do not rub the eye. If there is crusting, use a clean, wet washcloth to gently wipe the eye once or twice a day. Never put the washcloth into the eye or use the same part of the washcloth twice. Avoid putting any pressure on the eye.
Over the following weeks, you should avoid strenuous activity that causes you to become red in the face, as straining increases pressure in the eye. If it is necessary to cough or sneeze, do so with your mouth open. Do not lift, push, or bend with your head lower than your heart.
Patients are allowed to return to the following activities unless otherwise instructed not to do so by the doctor:
• Patients may return to school or work if it does not involve strenuous activity or lifting.
• Pending the doctor’s advice, patients may drive a car if the corrected vision in the un-operated eye is 20/40 or better.
• Patients may shower – soap must be prevented from getting into the eye.
• Patients may shampoo their hair with their head tilted backwards. Patients may do light housework (do not lift, push, or bend with your head lower than your heart).
• Patients may do light housework (do not lift, push, or bend with your head lower than your heart).
• Patients may read, watch TV, do needlework until the eye(s) become tired.
Patients are prohibited from doing the following until otherwise approved by the doctor:
• Participate in sports (until approved).
• Strain or do any lifting (any activity which may cause your face to turn red).
• Bend with your head lower than your heart.
The Risks of a DSAEK
There may be mild pain, redness, stinging and/or itching for one week after surgery that usually responds to Tylenol. Serious infections or bleeding may occur in one out of 1000 patients. There is also a risk of developing high pressure in the eye (glaucoma) that is usually controllable with eyedrops.
During the surgery, the surgeon may find that it is not possible to continue or complete the partial thickness transplant surgery safely. As the safety of the patient’s eye is the highest priority, he may decide to change the surgery to a standard full thickness cornea transplant or halt the surgery altogether and reschedule it when new donor tissue is available.
After the surgery, dislocation of the partial thickness corneal transplant tissue within the eye is possible early in the post-operative period (days to weeks). Should such dislocation occur, repositioning of the tissue under local anesthesia (either in the office or operating room) would be required. If the tissue cannot be repositioned, a repeat partial thickness or full thickness corneal transplant may be necessary.
Your corneal transplant will most likely be successful and indeed, the rejection rate with DSAEK is significantly lower than with Penetrating Keratoplasty, however there is a possibility your body will reject the new inner corneal layer. Please click here to read more about the possibility of cornea tissue rejection.