The cornea is the clear front window of the eye. It transmits light to the inside of the eye, focusing it and allowing us to see clearly. Corneal injury, disease or inherited conditions can cause clouding, distortion or scarring. Like frost on a windowpane, corneal clouding blocks the passage of light to the back of the eye, reducing sight, sometimes even to the point of blindness. In addition, disease or injury of the sensitive cornea can cause some of the most intense pain we can experience.

Diseases and disorders of the cornea

Corneal Edema
Corneal edema, or swelling, can sometimes occur after cataract surgery or due to diseases such as Fuch's dystrophy. Left untreated, this swelling can cause blurred or foggy vision. If swelling advances to the point where tiny blisters form on the surface of the cornea, it can become very painful. This condition can be treated with eye drops or ointments, but in some cases, it is necessary to perform a corneal transplant. 

Corneal Dystrophy
The word "dystrophy" means "abnormal growth." Thus, the term "corneal dystrophy" means there is a problem with normal cell growth in this part of the eye. Over 20 different types of corneal dystrophy exist. These diseases share many traits:

• They are usually inherited.
• They affect the right and left eyes equally.
• They are not caused by factors such as injury, activity or diet.
• They are not usually related to other diseases in the body, nor do they generally affect other parts of the body.
• Most occur in people (both men and women) who are otherwise totally healthy.

Corneal dystrophies affect vision in very different ways. Some cause severe visual impairment, while a few cause no vision problems at all. Others may cause recurrent episodes of pain without leading to permanent vision loss. Some dystrophies are associated with repeated episodes of foreign body sensation (the feeling that there is "something in the eye") called recurrent erosions. Some patients with corneal dystrophies will eventually require a corneal transplant in order to see well again.

Keratoconus
This condition involves progressive thinning of the cornea, resulting in an abnormal shape (ectasia). It is often first discovered in patients who are in their teens to mid-twenties. In keratoconus, the middle of the cornea thins and gradually bulges outward, forming a rounded cone shape. This abnormal curve produces moderate to severe visual distortion (astigmatism) and blurry vision. In the early stages of the disorder, the shape can easily be corrected with glasses or contact lenses. However, if your vision becomes too distorted or scar tissue begins to form, corneal transplant may be necessary. For most patients with keratoconus, the surgery is highly successful at restoring normal vision. Pellucid marginal degeneration is another disorder very similar to keratoconus, but much less common. 

Other Disorders
This brochure discusses some of the most common reasons for corneal transplant surgery. However, there are many other conditions, such as chemical injuries, accidents, lacerations (cuts), infections, or growths on the cornea that could also result in the need for a corneal transplant. If you have questions about your specific eye condition, you should feel free to discuss them with your physician. 

The operation itself consists of removing the cloudy, scarred or otherwise damaged cornea and replacing it with the clear, central portion of a donor cornea. The healthy tissue is sewn in place with fine sutures that remain in place for up to two years, until the cornea is adequately healed. Following surgery, prescription eye drops that facilitate healing are needed for several months. Vision returns slowly, often taking up to two years to stabilize completely, but you should be able to resume normal activities soon after the operation.

Corneal tissue for transplantation comes from volunteers who have asked that when they die, their healthy corneas be donated to those who need them. Donations are handled through a donor program, which processes the tissue. An eye bank preserves and screens donated tissue carefully before transplants take place to make sure it is free of any type of transmissible disease.

Your surgeon's office will assist you with all the requirements for pre-operative testing, insurance billing and preauthorization. You will need to have a physical examination, either by your surgeon or by your regular physician (primary care provider). If you see your own physician, the surgery coordinator will give you a checklist for your physician to complete. 

In addition, please observe the following:

• Do not eat or drink anything after midnight the night before surgery unless instructed to do so.  If you do eat or drink when you have been instructed not to do so, your transplant may need to be rescheduled.
• Leave a telephone number where you can be reached the night before surgery. The anesthesiologist may try to contact you to discuss the procedure and your anesthesia. The surgery coordinator may also need to reach you if there is no suitable transplant tissue available and your surgery needs to be postponed.
• Bring a driver with you when you report to surgery. While you will likely return home the day of surgery, you will not be released without a driver, as your vision will not allow you to drive immediately after surgery. You will not be able to proceed with your surgery if you do not have a driver.
• Bring all your current medications with you. Tell your surgeon about any allergies you have.

Some types of medications should be stopped prior to corneal transplant surgery with the knowledge and permission of your primary care physician. If you routinely take aspirin or other pain medication, you should make every effort to discontinue these medications prior to surgery. If you take these medications for heart or blood vessel problems (heart disease, stroke, blood clotting problems), tell your surgeon and consult your primary care physician prior to stopping the medication. 

The following is a list of drugs that may interfere with blood clotting during and after surgery. Consult your surgeon about stopping the following medications if possible.

Depending on where you have your surgery, you may be given a kit with your eye drops or a prescription to fill for eye drops.  Your surgeon will advise as to when you should start using your eye medication following your corneal transplant.

It is important to use your medications (drops, ointments and anything else the doctor may prescribe) exactly as instructed.  For the first four months after surgery, you must also keep your eye protected at all times. You may wear your glasses or a metal shield given to you after surgery.

If you already use eye drops for another eye disease (glaucoma, for example), you will probably need to continue these drops in addition to the ones you are given after your corneal transplant. Check with your doctor before taking them. It is important to notify your pharmacist or surgeon when you begin to run out of your eye drops.  Do not stop using your medication simply because the bottle or tube is empty. Stop the medication only when your doctor tells you to do so. Bring all of your eye medications with you to each appointment, including those you used before surgery.

Regular follow up ("post-op") visits will be scheduled after your surgery. These visits are an integral part of the surgical process and are important to ensure your eye is healing properly. The frequency of post-op visits immediately after surgery varies from surgeon to surgeon, but can include exams at one day, two days, one week and two weeks after surgery. The frequency of visits thereafter will decrease depending on how your eye is healing. 

The vision in your operated eye will be blurry for approximately 12 months after surgery. As the eye heals, your vision will slowly improve. If necessary, some of the sutures may be removed as early as a few weeks after the corneal transplant. Glasses or contact lenses might be prescribed starting as early as 6 months after surgery. It will take up to two years for vision in the operated eye to reach its maximum level.

Most daily activities can be resumed soon after a corneal transplant. You may bathe or shower, but avoid getting soap or water in your operated eye. Do not swim until your doctor gives you permission to do so. 

For the first two weeks after surgery, do not lift anything weighing over 25-30 pounds. Bending and stooping are allowed, but hold onto something for balance, and try to keep your head above your heart. Avoid strenuous exercise for the first two weeks after a corneal transplant. Avoid sleeping on the same side as your operated eye for two weeks after surgery. Above all, protect your eye from being bumped or poked.  Do not press on or rub your eye. 

You may watch television or movies or read as much as you like. If necessary, you may undergo other surgical or dental procedures; you can also vacation, fly in an airplane, cook, sew or do anything else you feel able to do in moderation. You may return to work as soon as you feel able (most patients take one to two weeks off). 

I've heard that corneal transplants are sometimes rejected. Should I be concerned? What signs should I watch out for?

Corneal transplants are one of the most commonly performed and successful transplant surgeries in the United States today. Approximately 40,000 operations are performed in this country each year. Of these, only about 10% of patients (1 out of 10) experience a rejection, which results when your body identifies the new cornea as foreign tissue and attempts to destroy it. In a rejection, the transplanted cornea clouds and vision deteriorates, but the tissue is not sloughed.

Rejection of the donated tissue can occur at any time, from several weeks after surgery to years later, and it may occur more than once. If a rejection episode is detected and treated early, however, the process can often be reversed with medication. 

R S V P is an easy way to remember the symptoms of corneal transplant rejection. 

• Redness: the eye becomes very red.
• Sensitivity: the eye becomes very light sensitive.
• Vision Loss: the vision in that eye seems to have decreased suddenly.
• Pain: the eye becomes very painful.

If you experience any of these symptoms after your surgery, call your surgeon immediately.

Most corneal transplant surgery is uncomplicated and places few limitations on patients' activities. However, proper attention to follow-up care and prompt medical attention to any complications are essential to achieving a successful transplant.

This information provided by Casey Eye Institute, Oregon Health and Sciences University, 2005.