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Cornea

Understanding Corneal Transplant Surgery

Introduction

Corneal transplant surgery is quite common; some 5,000 transplants are done in the United States every year. In recent years, the chances of success of this operation have risen dramatically because of new advances such as the surgical microscope, finer, less irritating sutures, and better eye banking techniques. In fact, many patients can expect better than a 90% chance of a clear transplant. Even though this surgery is a unique and sometimes frightening experience for you as a patient, we hope that this section will help to guide you through this new experience by answering questions concerning corneal transplant surgery and your role in ensuring its success.

What is the Cornea

Corneal transplant surgery involves removing the diseased cornea surgically and replacing it with a donated cornea. To help you better understand this, let us briefly describe just what the cornea is.
In the healthy eye, the cornea is a clear, dime-sized piece of tissue that fits like a watch crystal over the blue or brown-colored part of the eye called the iris. Light passes through the cornea (just as it would through a window), through the pupil, then through the lens. The cornea and lens focus light rays on the retina in the back of the eye. The retina then transmits the image of sight along nerves to the brain.
The eye is like a camera in which the retina acts as the film and the cornea and lens act like two lenses of the camera. Cloudiness or irregularity of the cornea or of the lens of the eye results in a blurry image, just as a faulty camera lens would result in a poor photograph.
Corneal cloudiness or irregularity can result from many different kinds of diseases, such as infections, injuries, or inherited tendencies towards a cloudy cornea. In addition, the lens of the eye may become cloudy; this is called a cataract. Depending on the problem, a person might need just a new cornea or a new cornea with removal of the cataract.

Obtaining a new cornea is what happens in corneal transplant surgery. This operation is sometimes called corneal graft surgery or penetrating keratoplasty. We will use the term corneal transplant surgery. Your eye is the recipient eye; the other person's cornea is the donor cornea or donor tissue.

The Operation

We perform the surgery while looking through a microscope in order to do this very delicate work with great precision. A trephine, an instrument like a cookie cutter, is used to remove your cloudy cornea. A trephine cuts out the donor graft to ensure that its size and shape are right for the opening made in your cornea. Bleeding is minimal, amounting usually to only one or two drops of blood.

The new corneal transplant is placed in the opening and is sewn or sutured with a very fine thread, often finer than a human hair. This thread or suture stays in for months or even many years until your eye heals properly; in some instances the suture is left in permanently. Removing the suture is quite simple and can be easily done in the office.

Anesthesia

Corneal transplant surgery is routinely performed with either local or general anesthesia. The best method for you will be discussed with you by Dr. Khater.

If the surgery is performed under local anesthesia, you will be temporarily put into a light sleep with an intravenous medication; the local anesthesia will then be injected in the area around the eye. In most instances, patients do not feel or even remember this injection. Afterwards, your eye will be totally numb and the surgery can be performed while you are awake, but lightly sedated.

If the surgery is performed under general anesthesia, you will be put to sleep, and a plastic tube will be placed in your windpipe to breathe for you. Again no eye pain will be experienced.

Both methods of anesthesia are carefully monitored by an anesthesiologist, and both methods can be done on an outpatient basis.

After Surgery

Caring for your corneal transplant after surgery depends, in large measure, on you. We must work together well, and you must follow strictly the instructions on how to care for your precious new transplant. You will need to use eye drops for many months (or years), and we, or your referring ophthalmologist, will need to see you regularly in the office. There will be certain restrictions on your activities in the early period after your surgery. These will be explained later.

Chances of Success

In most cases the successful outcome following corneal transplant surgery depends on the type of corneal disease that was originally present. When the eye receiving a corneal transplant is perfectly healthy except for cloudiness of the central cornea, the chances of a clear transplant are greater than 90%. But to be successful, you must follow the strict schedule of drops and office visits. Failure to follow the prescribed schedule could greatly reduce the chances of successful surgery. Here are some problems that could delay or prevent the return of useful sight in your operated eye.

Primary Transplant Failure: Fortunately, this is rare. It occurs in the first week or two after surgery and is caused by a fault in the donor cornea. The only treatment is to do another transplant with a different donor cornea.

Graft Rejection: This is quite unusual. It happens when the body becomes "allergic" to the graft and can occur at any time two weeks or more after surgery. There is a good chance that this can be successfully treated if you act immediately. There are four danger signs that you must know. If any of these occur and last for more than six hours, you should immediately call us. These signs are:

Red Eye: It is normal for your eye to be red in the first few weeks after surgery. If, at any time, your eye begins to get redder, then this is cause for concern and you should call your ophthalmologist. You can easily check the redness of your eye by looking into a mirror and pulling down the lower lid. Look carefully at the white part of the eye, especially in the area next to the cornea. You might even check your eye periodically even if you're not having any problems, so that you will know what it looks like when it is normal.

Decreased Vision: Even though it can take weeks or months to get good vision after you've had your transplant, your vision probably will be gradually improving after your surgery. Pick an object in your house that has some pattern or detail to it and get in the habit of covering your good eye and looking at this object every day. In this way you can tell how your vision is doing. If your vision seems to be getting worse, there could be a problem with your eye, and should call us.
Pain: It is normal to have occasional small twinges of pain in your eye but if your eye develops constant pain for several hours, please call us.
 
Increased sensitivity to light: Bright light might seem very irritating to your eye after surgery. This should slowly get better. If you notice that your eye seems to be getting more sensitive to light and that you feel like squinting or covering it, you should call us.
Wound Separation: This is a break in the area where the edge of the graft is sewn into the eye. There might be no symptoms at all or only a dull ache. It may be treated with a light patch or soft contact lens or it may require a trip back to the operating room so that additional suturing of the transplant can be done.

Astigmatism: This occurs when the transplanted corneas has an oblong shape similar to the surface of a football rather than the round shape of a basketball's surface. All transplants have some amount of astigmatism and usually this can be corrected with glasses or contact lenses. If this astigmatism is severe, a refractive procedure can often correct it.

Loose Suture: This is not uncommon. Sometimes during the healing process sutures can loosen and case a foreign body feeling, especially when you blink. The loose suture can easily be removed in the office.

Macular Edema: This is a swelling from fluid that has collected in the retina in the back of the eye. It occurs most commonly if the eye has previously undergone cataract surgery. The only symptom is a painless loss of vision. This fluid cannot be surgically drained, but the condition often improves on its own or may respond to certain pills and eye drops that we prescribe.

Considerations Before Your Surgery
Outpatient vs. Inpatient Surgery

Our experience with outpatient corneal transplant surgery indicates that it is as safe for most patients as inpatient surgery, and it certainly is less stressful. Most patients can now arrive at the hospital on the morning of surgery and leaves within one hour after surgery has been completed. We do our outpatient corneal surgery in the same quality operating suites that we use for inpatients, and so you have the benefits of the highly-skilled nurses and superb facilities of The Methodist Hospital combined with the convenience of lower cost of outpatient surgery.Of course, we do admit those patients who for medical reasons require it, but we find that most of our patients can benefit from outpatient surgery.

Planning Postoperative Care

If you have a referring ophthalmologist, our staff will be happy to schedule your postoperative visits with that ophthalmologist. We are happy to provide postoperative care for as long as your referring doctor wishes.

Postoperative visits are routinely scheduled for the following intervals after your surgery: 1 day, 5-7 days, 3 weeks, and 6 weeks.  This may vary according to your particular circumstances. Subsequent visits are usually at monthly or bimonthly intervals during the first year after surgery.

If you live too far away to have follow-up care with us, and you have no referring ophthalmologist, then we will be happy to work with you to find an ophthalmologist near your home who can provide you with your postoperative care.

Your personal eye care after your surgery will mainly involve putting eye drops into the operated eye for several months or longer, beginning with 4 times a day and then at gradually decreasing intervals. We find that almost all individuals can learn to put drops in their own eyes. If, however, this is not possible for you, please be sure to arrange for someone to help you use the eye drops at home.

General Medical Precautions

If you have medical problems that require the care of a physician, a recent written report from you physician would be helpful to us. If you doctor has a preference concerning the use of local vs. general anesthesia in your case, please let us know. In most cases we will use local anesthesia; that is, you will be awake during the operation.

Stop taking any medication containing aspirin 7-10 days before surgery. If you are taking a "blood thinner" such as Coumadin, this will need to be stopped a few days before surgery: please check with your doctor for exact instructions. Also, please consult with your doctor concerning when and if you should stop taking any other medications. Bring all medications that you are currently taking when you come for your office visit on the day before surgery.

If you experience fever or infection in any part of your body within 2-3 weeks of your scheduled date of surgery, it is likely that we will want to reschedule the surgery for a later date. In such an event, check with your general medical doctor and/or this office for a decision about rescheduling.

Your Vision After Surgery

In the months following surgery the vision in your eye will slowly improve. This improvement is variable because the healing of the corneal transplant varies from patient to patient. In general, useful vision can be obtained within two to six months. About this time, you may be given a prescription for glasses or a contact lens. As your corneal graft heals, your prescription for glasses will probably change.

The suture holding your graft in place is usually allowed to remain in the eye for a year or sometimes longer. When the suture is removed, a substantial change in your eye glasses prescription will occur. This suture can easily and painlessly be removed in the office.

Even after the suture is removed, you should always see an ophthalmologist following your corneal transplant surgery. You will need to use eye drops for a year or sometimes more depending on your particular situation.