About Corneal Transplant – Causes, Procedure, and Recommendations: The cornea is the clear “shell” at the front of the eye. The cornea plays a key role in focusing our vision. It focuses light rays, letting them pass through to the back of our eye and onto our retina, where images are transmitted to our brain and then interpreted as sight. If anyone has corneal disease or injury, transparency may be lost and vision is impaired. If that happens, a corneal transplant becomes the only solution. Corneal transplants give back patients’ corneal transparency helping to restore vision.
A corneal transplant is a surgical procedure to remove the damaged cornea and replace it with a healthy donor cornea. This process is called corneal transplant, corneal graft, or corneoscleral transposition. In this blog we will discuss Corneal Transplant – Causes, Procedure, and Recommendations.
The most common reason for a corneal transplant is due to damage from an injury or disease. Other reasons for this type of eye surgery are to correct corneal disorders, including keratoconus, corneal scars due to infection, injuries, and degenerative conditions of the cornea.
Several conditions can be treated with corneal transplants that are
• Thinning or tearing of cornea
• Keratoconus, when cornea bulges outward
• Hereditary conditions (Fuchs dystrophy)
• Scarring caused by injury or infection
• Swelling of the cornea
• Corneal ulcers that cannot be treated medically
• Complications caused any previous surgery
The cornea is normally about as thick as a pencil eraser but can swell much thicker when affected by disease or trauma. An optometrist or ophthalmologist may recommend corneal transplant surgery if the cornea becomes too cloudy or severely diseased to see through clearly; it generally does not help with milder cases of corneal clouding.
Corneal transplant surgery is performed by an ophthalmologist, a surgeon specializing in eye problems and eye surgery. It involves replacing the cornea with tissue from a deceased donor cornea. The surgeon first removes diseased corneal tissue and then replaces it with a donor cornea.
If a person needs a corneal transplant, his ophthalmologist will recommend appropriate therapies to manage his condition while waiting for a suitable donor. If no treatment is available, he will be placed on the waiting list until a cornea donor becomes available.
After the diseased cornea (or part of it) has been removed by an ophthalmologist, the new cornea is sewn in place, allowing light to pass through it and projecting images on his retina for interpretation by his brain. His body will recognize this new tissue as foreign; hence, he’ll need ongoing medical treatment with antirejection medications after corneal transplant surgery.
There are three main types of corneal transplant procedures: full thickness, partial thickness, and lamellar/lamellar-like procedures. Of these three procedures, partial-thickness transplants are most often used, due to their efficacy at preserving endothelial cells (cells that line the corneal surface), which play an important role in corneal health and clarity. Though corneal transplant is becoming a common procedure to restore vision, several steps are necessary to ensure corneal transplants success.
Penetrating Keratoplasty (PK) full-thickness¬¬ cornea transplant. The eye surgeon will cut the entire thickness of the diseased cornea to remove a small button-sized disk of corneal tissue. To make this cut precisely a special instrument is used by medical professionals. The donor cornea is then fitted in the opening. The surgeon then stitches the new cornea into place and the stitches are removed after a few days.
In this procedure, the diseased tissue is removed from the back layers of the cornea. This includes endothelium and the thin tissue that protects endothelium from injury and infection. Then this tissue is replaced by healthy donor tissue.
There are two types of endothelial keratoplasty. The first type, called Descemet stripping endothelial keratoplasty (DSEK), requires donor tissue to replace almost one-third part of the cornea.
The second type, called Descemet membrane endothelial keratoplasty (DMEK), requires a much thinner layer of donor tissue. The tissue which is used in DMEK is extremely thin and fragile. This transplant procedure is more complicated than DSEK but it is more demanding and commonly used.
In this procedure, two different methods are used to remove the diseased tissue from the layers of the cornea and leave the back layer in place. The severity of corneal damage determines the type of procedure.
Superficial anterior lamellar keratoplasty (SALK) replaces the front layers of the cornea and leaves the healthy stroma and endothelium in place. This procedure is used when the cornea is damaged deeper into the stroma. Healthy donor tissue is then placed.
Artificial cornea transplant (keratoprosthesis) is the replacement of diseased corneal tissue with an artificial cornea. The decision is mostly taken for bilateral end-stage corneal blindness. It requires prolonged follow-ups and post-op care.
Before the transplant at the time to transplant, the patient is given a sedative to help him relax and then an anesthetic is given to numb the defective eye. The patient doesn’t feel pain at any time. The transplant surgery is done on one eye at a time.
After the procedure, the transplant is completed the patient should:
• Receive all medications. Take eye drops and oral medications immediately after the cornea transplant is done and during the recovery process. This will help control any infection, pain, and swelling. Eye drops should be taken to suppress the immune system prevent corneal rejections.
• Wear eye protection. Wear eyeglasses to protect the eyes from sunlight and dust
• Lie on your back. The patient might need to lie on his back for a while to help the new tissue stay in its place
• Avoid injury. Do not rub or press the eye. Do not perform any strenuous activity to avoid injuries and take extra precautions to keep your eyes safe from any harm
• Follow-up exams. See the eye doctor after the surgery and do regular visits within a year to examine the progress and look for any complications
If you have a corneal transplant, you will need to take care of your eyes following surgery to ensure that your vision improves and stays healthy. You should make an urgent appointment with eye specialists if you feel any signs of corneal rejection such as
• Loss of vision
• Eye pain
• Red eyes
• Sensitivity to light
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