Corneal Transplant by a Skilled Ophthalmologist
What is the cornea and what is a corneal transplant?
The cornea is the transparent front portion that permits light to enter and focus on the retina. Normally crystal clear, the cornea can become cloudy or misshapen, causing gravely reduced vision or blindness. Diseased corneas can be replaced successfully through transplantation of human donor corneas.
Ocular conditions that result in irreversible scarring, swelling, or thinning of the cornea require a corneal transplant in certain instances to restore vision. Each year approximately 40,000 corneal transplants are performed in the United States Corneal transplantation is the most successful of all the organ and tissue transplantations performed.
In a corneal transplant operation the central portion of the cornea is replaced with tissue donor cornea from an individual who has donated his cornea to a local eye bank after death. This cornea has been screened for all transmissible diseases such as hepatitis and HIV.
Corneal transplant operations is an outpatient procedure that is performed under local anesthesia and usually takes about one hour. Stitches are placed to secure the donor cornea to the rim of the patient's existing cornea. About four weeks after corneal transplant procedures at our office,they will start to remove the individual stitches from the patient's eyeball to facilitate healing. The best visual acuity that a patient will achieve after corneal transplant operation will usually occur no sooner than three months after the procedure.
After the vision has stabilized, which occurs approximately three months after the operation, patients are prescribed new spectacles. In some instances, they will need to wear a contact lens in the treated eyeball to achieve the best-corrected vision. Eight months after corneal transplant procedure at our office, the doctor will decide whether to remove the running suture. This depends on how it has healed and the amount of residual ocular impairment.
If you would like to speak with a skilled specialist who performs corneal transplants, contact our ophthalmologist office. You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
Common reasons a patient needs a corneal transplant
The following paragraphs describe the common reasons a patient needs a corneal transplant. Residents in the northeast United States should contact our ophthalmologist office if they suffer from any of the corneal disorders below.
The most common causes of corneal clouding are traumatic injury to the cornea, complications following the operation, hereditary disorders, and corneal scars caused by infectious agents such as bacteria or herpes simplex virus. These can result in partial or total vision loss depending on the severity of the damage.
Keratoconus is a disease entity that affects the crystal clear front part of the cornea. In this disease process, the crystal clear cornea becomes cone-like and thinner over time. The number of layers of the cornea decrease, and the jelly-like substance that separates the layers decreases. The increasing curvature of the cornea leads to progressive loss of sight and a distortion of the corneal surface called irregular astigmatism. The cause is unknown, and there is no medical cure available at this time.
Medical (Non-Surgical) Treatment of Keratoconus
In the early stages, keratoconus can be treated by spectacle lenses alone. As the disease progresses and as irregular diffuculties progress, specially designed keratoconus contact lenses can be used to provide patients with years of good vision. The contact lenses are able to correct vision because they mask or cover up the abnormal curvatures on the front of the cornea.
As keratoconus advances, more contact lens fits are required. Patients begin to see a second image with each individual eye. The contact lenses can only be tolerated for a few hours at a time before they must be removed due to ocular irritation and discomfort. Sometimes the lenses will begin to dislodge from several times a day. At this point, very specialized contact lens fitting techniques can be utilized. One choice is to have a patient wear a soft contact lens and then wear a hard contact lens on top of that, the so-called piggyback technique. This technique is very expensive. Several hours of fitting are required and it is successful in less than 5 percent of patients. An alternate is the new SoftPerm contact lens concept in which the central part of contact lens is made from gas-permeable lens material whereas the surrounding donut-shaped skirt is made of soft contact lens material.
The success rate of this type of lens for keratoconus, in cases that are advanced enough to require it, is also small. When patients reach a stage in which they can no longer achieve satisfactory vision with spectacles and contact lenses, they become surgical candidates for the treatment of keratoconus.
Surgical Treatment of Keratoconus
The surgical option to the treatment of keratoconus is a full-thickness corneal transplant (penetrating keratoplasty) that has a very high (greater than 95 percent) success rate. With this technique, approximately 80 percent of the cornea is removed and replaced with a healthy donor cornea from a donor. This requires the placement of sutures and is usually performed under local anesthesia. Today, this corneal transplant procedure is most often performed as an outpatient in an ambulatory treatent center, and patients can go home within one or two hours after the operation.
Success Rates and Risks for Keratoconus
Corneal transplants for keratoconus generally have over a 95 percent success rate. Most keratoconus patients have good healthy corneas with healthy blood vessels and no scarring. Cataract procedures with corneal transplants are usually not needed, although in rare circumstances it is necessary.
The risks are the same for any procedure in which the eye is entered: infection, bleeding, high pressure, retinal detaching, amaurosis formation, transplant rejection. If the cornea is rejected it turns cloudy. If the patient seeks help early in the rejection process, more than 75 percent of the cases can be successfully managed with medication. Corneal transplant operations can be repeated if the corneas are rejected.
Because so little is known about keratoconus, ongoing research is being carried out in laboratories across the country.
Pseudophakic Bullous Keratopathy - Corneal Edema (swelling)
This is a condition in which one's cornea has become permanently swollen (corneal edema) following cataracts and intraocular lens implant procedure. The cells that line the back inside surface of the normally crystal clear cornea (the endothelium), for one of various reasons, have been injured permanently. The function of the endothelium is to pump water out of the cornea, keeping it crystal clear and thin. When injured, these cells can no longer perform this function. The fluid that circulates inside the eyeball seeps into the cornea, causing it to swell and to become cloudy. This condition is called pseudophakic bullous keratopathy.
The causes of endothelial cell damage following cataract operations are multiple. They include physical trauma during the operation, such as difficulties in removing the cataract or inserting the intraocular lens, severe inflammation following the operation, intraoperative bleeding, or a predisposing disease called Fuchs' endothelial dystrophy that makes the cornea prone to losing endothelial cells. When one is afflicted with pseudophakic bullous keratopathy, the cornea is permanently swollen and no medications, spectacles, or contact lenses can improve the vision of a patient with this condition.
Success Rates and Risks for Bullous Keratophy
Statistically, corneal transplants for pseudophakic bullous keratopathy are highly successful with over 90 percent of the corneas remaining crystal clear. However, the success rate for visual acuity recovery is lower because many of these patients have had predisposing problems in the retina, such as edema (fluid) collecting on the retina (macula), a condition called cystoid macular edema. Other patients have had severe bleeding with damage to the optic nerve. These two processes tend to limit the best-corrected vision even though a successful operation and a clear corneal transplant are obtained. Statistical analysis of cases published in the scientific ophthalmology literature reveal that approximately one-third of the patients with pseudophakic bullous keratopathy recover 20/40 vision or better after corneal transplant procedure, one-third recover between 20/50 and 20/200 vision, and one-third do not recover good vision. Analysis of his own cases has demonstrated better results. It is not possible to determine which of the above groups a patient will end up in prior to corneal transplant operation.
Fuchs' Endothelial Dystrophy
The normally crystal clear cornea has a layer on its inside surface called the endothelium. The purpose of this layer of cells is to pump water out of the cornea keeping it crystal clear and thin. Normally, as we age, these cells can become thick and fat. When the ophthalmologist looks at your eyeball through the slit lamp microscope, these cells can be detected and are termed guttata. Guttata are part of the normal aging process of the corneal endothelium.
Fuchs' endothelial dystrophy was first described more than 100 years ago. It is a process in which guttata occur throughout the entire back surface of the cornea and appear one to three decades earlier than is normally expected.
In Fuchs' endothelial dystrophy, as the guttata increase in size and numbers, fluid begins to accumulate within the cornea. Patients develop blurry or foggy vision in the morning, see halos around lights early in the morning, are unable to read in the early part of the day, etc. As the day goes on and the cornea dehydrates on its own, it becomes clearer and thinner and the patient's vision improves. As the process of Fuchs' endothelial dystrophy progresses, the swelling of the cornea persists further on into the day until eventually the vision never clears.
Surgical Treatment of Pseudophakic Bullous Keratopathy & Fuch's Endothelial Dystrophy using the DSEK procedure:
In both pseudophakic bullous keratopathy and Fuch’s dystrophy, only the endothelium is diseased-the remaining layers of the cornea are usually normal and healthy. Until recently, the treatment of choice in patients with corneal edema from endothelial cell loss was a corneal transplant operation (penetrating keratoplasty). This involves replacing the entire cornea using a full thickness donor cornea. Recently a new procedure was developed to treat this condition called DSEK. DSEK stands for Descemets’ stripping endothelial keratoplasty. In this procedure, the damaged endothelium is stripped and removed from the patient’s eye and replaced with a partial thickness piece of donor cornea containing a healthy endothelium (posterior graft). Dr. Pamel was one of the first people in New York to perform this technique on patients.
This procedure is done through a sutureless incision and therefore results in a faster visual recovery. Most patients recover useful vision (20/60 or better) within three months of surgery compared to a full thickness corneal transplant which may take up to a year or longer to achieve the same level of vision. Dr. Pamel no longer recommends performing a standard corneal transplant on most patients with pseudophakic bullous keratopathy or Fuch’s dystrophy unless they significant corneal scarring.
The Corneal Transplant Procedure
Replacement of a clouded cornea is the only means of restoring full vision. If the rest of the eyeball (including the retina and optic nerve) is normal, the cornea can be replaced through transplantation. The success of the corneal transplant procedure depends on the amount and type of damage it has sustained from disease or injury. The success rate can be as high as 95 percent. However, it is important to remember that vision can be restored to normal levels only if the remainder of the eyeball is normal.
Approximately 36,000 corneal transplants are performed each year in the United States. The success rate of the procedure has increased dramatically in the past few years because of recent advances in research and surgical techniques. Corneal transplant operations, performed at our office, is considered to be the most successful of all organ transplant surgeries.
Only the central portion of the cornea is involved in corneal transplantation. The doctor excises an appropriate portion of the patient's cornea and replaces it with a similarly sized donor cornea, which is then sutured into place. The normal diameter of the human cornea is 12 mm. A majority of transplants have diameters of 7.5 to 8.5 mm and hence perform well within the perimeter of the average cornea.
A corneal transplant is an extremely delicate microsurgical procedure performed with the aid of an operating microscope at magnifications of 10 to 25 times. Dr. Gregory Pamel uses a suturing technique for the corneal transplant procedure. This technique employs a combination of interrupted sutures that are one-fifth the diameter of a human hair and continuous sutures that are one-tenth the diameter of a human hair. Since 1991, our office has been using an automated trephine (the instrument that removes the diseased cornea) so that a more perfect incision can be made.
The advantage of these techniques is that they permit the curvature of the cornea to be adjusted by selectively removing individual sutures after the operation, thereby allowing the patient to see better more quickly than with suturing techniques currently employed by other corneal physicians.
If you would like to speak with a skilled specialist who performs corneal transplant operations, contact our office. You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
The Eye Bank Network
Corneas for corneal transplant procedures come from individuals who have donated their eyes to be used after their death for the benefits of others. Donor corneal tissue can be used for up to seven days after death of the donor. A nationwide eye bank network facilitates the distribution of donor tissue, usually within 24 hours. The eye bank screens all tissue carefully to ensure that it is healthy and in excellent condition. This includes screening for diseases such as hepatitis and AIDS.
With few exceptions, donor tissue from individuals ranging in age from one to 65 is usable. Factors such as sex, race, color of the iris, or the previous vision of the donor have no influence on the surgical result. Since we use a nationwide network of eye banks to obtain corneal tissue, patients do not have to be placed on a waiting list for their corneal transplant at his office.
Risks in Corneal Transplant Operations
As with any operation, there is the possibility of loss of sight, loss of the entire eyeball, or possible loss of life due to abnormal reactions to anesthesia. These risks are very small, but it is important that you be aware of them. There are no guarantees with corneal transplants , just as there are no guarantees with any other type of procedure.
Some of the possible complications that could occur are infection, bleeding, high pressure, a wound leak, poor wound healing, and failure or rejection of the transplant.
Instructions for Patients Awaiting Corneal Transplantation
What to expect while in the hospital or treatment center
The night before corneal transplant procedure, patients will not be permitted to eat or drink anything after the midnight. An anesthesiologist will discuss with the type of anesthesia the patient will have, which in more than 99 percent of the cases is a local anesthetic with IV sedation. Only your eyes will be anesthetized. Most corneal transplant surgeries are performed under local anesthesia, but occasionally general anesthesia is indicated.
Before going into the operating room you will receive some medications. Drops will be put in the involved eye. The doctor will greet you in the operating room, as will any assisting doctors and nurses. During the corneal transplant operation, the patient will be fed intravenously. The patient will have all vital signs monitored including heart rate, blood pressure, and the blood's oxygen content.
After the corneal transplant procedure, a patch will be placed over the operated eyeball, and you will be returned to your room or postoperative area. You will be permitted to eat, talk with friends, and go to the bathroom with assistance and will probably be able to check out of the facility. The doctorwill see you in his private office the next day to remove your patch and check your progress. At this time, you will receive drops and any other necessary medications. Please use them as directed. The purpose of the drops is to make you comfortable, decrease the amount of inflammation, and prevent possible infection. Any build-up of mucous or dried tears that accumulates around your eye can be eliminated by placing a drop of your antibiotic drops on a cotton-tipped applicator, such as Q-tip, and rubbing it gently on the eyelid margin where your lashes and skin come together.
To contact a skilled specialist who performs corneal transplant operations, contact our office today. You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
The Recovery Period
Following the corneal transplant, your second visit to our office will be in five to eight days after the procedure. There will be subsequent visits every two to eight weeks depending on the type of operation and the state of healing. Sutures are not removed during this period, but they may be cut to control the amount of post-surgical trouble. Sutures are removed at a time appropriate to each individual patient; there are no specific rules. In general, the earliest that sutures will be removed is at four to six weeks. They may stay in place for two to three years or longer. A contact lens or eyeglass will not be prescribed for you until your transplant has begun to heal - no sooner than three months.
Following corneal transplant operations, you may continue most of the activities of daily living with the exception of those that put stress on the eye or subject it to trauma. Specifically, you should not lift anything that weighs more than 30 pounds or perform any function that will cause you strain. At no time should you allow your head to bend lower than your waist, as this puts pressure on the eyeball. Be very careful to avoid direct trauma, such as bumping it with your hand or any other object.
You may protect yourself with either regular spectacles or a metal shield during the day. The metal shield must be worn at night for one month. It is then discarded. You may shower, shampoo, or shave, but you should take special care to avoid getting soap in your sutures. If that should occur, flush it with your antibiotic drops or artificial tears to remove the soap. You may read and watch television, as these activities will not hurt you. You may return to work as soon as you feel ready, but it is prudent to wait at least three to seven days after a corneal transplant procedure.
Your wound will be weakest after all the sutures are finally removed, so you must be especially cautious for at least two weeks after the final removal of all sutures.
If you would like to speak with a skilled specialist who performs corneal transplant operations, contact our office. You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
Proper Use of Medications
After a corneal transplant procedure, it is important to use medications exactly as instructed. Do not skip doses, and never use medications more frequently or for a longer time period than prescribed. Medications should be stored at room temperature unless otherwise instructed by your physician or pharmacist. Do not share medications with anyone and do not transfer medications from one bottle to another.
Use your drops or ointment only in the eye. Keep droppers and tube tips clean. Avoid touching the tip of the dropper or tube to anything, especially the fingers or any part of the eyeball. Never use drops that have changed color. Drops or ointment can be placed at any time within an hour of the time scheduled. If you are using more than one drop, use them at least 10 minutes apart so that one drop does not wash out the other. Keep all medications out of reach of children.
Technique for administration of medication
(You may want to share this with a family member who can assist you)
If you have a question or concern about corneal transplantation and would like to speak with a specialist who performs corneal transplant operations, contact our office today . You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
Corneal Transplant Rejection
Please read this section on corneal transplant rejection with extreme care. Have other members of your family read it also, so that you will have the best possible chance for a successful corneal transplant.
Once the initial healing process begins (which usually requires 14 to 28 days), it should become white. Your vision should be slowly improving, and the it should be comfortable. Any sudden onset of pain, redness, or severely decreased vision might mean infection or a rejection episode.
Chances are excellent that your corneal transplant will be successful. If it should fail, it would most likely do so because your body recognizes the new corneal tissue as foreign and is trying to reject it. Rejection episodes can occur in up to 20 percent of cases and can occur more than once. A rejection attempt can occur as early as four weeks or as late as 10 or more years after corneal transplant procedure. By far the most common period of attempted rejection is within the first six months. After six months to a year, the chances of corneal transplant rejection are lower.
In 75 to 90 percent of cases, the rejection process can be reversed with medications if treated early and the corneal transplant will remain successful and clear. If the rejection attempt is not treated as soon as it occurs, the chance of eventual corneal transplant failure is much higher. It is extremely important for you to recognize the signs of attempted corneal transplant rejection and report them to us as quickly as possible to our office.
If you are unlucky and your body rejects your corneal transplant, it will turn cloudy but will not fall out. The doctor will wait at least two months before performing a repeat corneal transplant.
Three Danger Signals of Corneal Transplant Rejection
Early corneal transplant rejection is most commonly evidenced by a sudden but severe decrease in vision over a period of hours or days. After a corneal transplant procedure, daily fluctuations in vision are common. However, significant worsening of vision is uncommon.
Four weeks after a corneal transplant operation, start testing your vision in the following manner: Select an object on the wall of a room and back away until you can see a particular part of an object with the operated eye, keeping the unoperated eyeball covered. Note how far away you are from the object so that you can be consistent in measuring your vision. If your vision improves and it is easier to see the object from that distance, back away further to establish a new distance from which you can just see the object. If at any time you find that your vision has severely worsened compared to the previous day, you should call our office.
After a corneal transplant operation,it will be red because of blood in the tissue. As the blood clears, it should become whiter. If it becomes progressively bloodshot or red weeks after the corneal transplant procedure, this should be viewed as a warning signal of allergy or infection.
After the corneal transplant procedure there will be some discomfort, which should disappear in about a week. Because sutures are used, scratchiness, ocular irritation, or foreign body sensation are not uncommon. Most drops and ointments are soothing to the eye. Occasionally a medication may sting temporarily, but medicines should not produce pain or increase the amount of redness or swelling around the eye. Increased pain, redness, or itching could result from external irritants such as smoke or smog or could indicate an allergic reaction to one of the medications you are using.
If your eyeball should become increasingly sore or uncomfortable in any way after it has once become comfortable, this could be a sign of infection, high pressure, or attempted corneal transplant rejection.
We cannot guarantee you success with your corneal transplant procedure, but we can guarantee you an increased chance of success if you pay attention to these three danger signals. Be certain to know what they are and what to do if they occur.
If you would like to speak with a skilled specialist who performs corneal transplant operations, contact our office today . You can also call us at (212) 355-2215, or toll free at (888) 657-2010.
Use of Spectacles, Contact Lenses, or Intraocular Lens Implants After A Corneal Transplant
The use of one or more of these techniques to correct your vision will depend on your specific case. It may be possible to implant an intraocular lens at the time of corneal transplantation, but this will be determined by your individual situation and requirements.
LASIK Correction After A Corneal Transplant
Certain patients are unable to tolerate spectacles after corneal transplant operations because of a prpblem that occurs during the healing of the cornea. Astigmatism is a condition in which the cornea is shaped like a football instead of a basketball. After the corneal transplant procedure at our office, the problem in the operated eye may be too much to be tolerated in an eyeglass prescription.
Dr. Pamel may recommend trying a contact lens to correct the vision after corneal transplant operation but sometimes that is not tolerated either. At this point he may recommend a surgical option to reduce the problem either through incisions made on the surface of the cornea or through another procedure. It can be performed after corneal transplant procedure to reduce the vision problems, but only after all the sutures have been removed and the corneal shape has had a chance to stabilize. This is typically no sooner than one year after corneal transplant operation but depends on the healing properties of the individual patient.
Please call our office at (212) 355-2215, or toll free at (888) 657-2010, to speak with a doctor who performs corneal transplant operations. Contact our office today.