Corneal injuries or diseases can leave behind scars, blurring vision and causing other problems. Corneal transplants, a highly successful and intricate surgery is designed to restore vision to patients whose corneas have been damaged. During the procedure, the cornea is replaced with a healthy cornea, using human donor tissue.
Why is it done: Most often cornea is clouded due to trauma due to infections or surgery or mechanical trauma. Although the primary insult may have healed, it leaves behind a scar in the cornea interfering in restoration of the normal clarity of the cornea. However the cornea has a special protection that it is avascular making it a better host to receive new tissue from a donor. Over the years this technique has been improved and perfected and the post operative protocols have been standardised
Pre operative measures: It is essential that the primary insult is under control/inactive atleast for a period of 3 months before undertaking the surgery. Dr Charuta will guide you as to what medications will improve the chance of success of the planned transplant
How is it done:
The patient is given local anaesthesia which involves injection the area near the eye with a drug for ensuring that there is no pain during the procedure. Surgery involves removing a circle of tissue (about 8 mm in diameter) from the patient’s cornea. This is performed with special microsurgical instruments. A donor tissue is prepared by removing a matching circle of corneal tissue from the donated cornea. The new cornea is secured to the patient’s eye with delicate sutures, which are barely visible.
These sutures hold the tissue in place while the wound heals, which is a slow process. Additional surgery may be performed at the time of corneal transplantation to remove a cataract, replace an intraocular lens implant, control glaucoma or repair the retina. During the first few weeks after surgery, the vision is usually blurred but progressively begins to clear. After two to three months of healing, some of the sutures may be removed and spectacles may be prescribed to focus the vision. However, it may take six months or more before the full recovery of vision has been achieved.
The donor tissue is provided by an eye bank, which carefully screens the tissue. The Eye Bank association of India(EBAI) regulations require eye banks to screen all tissue for HIV, hepatitis, and a variety of other diseases. Only healthy tissue, which is free of disease, may be used for transplant surgery.
A national collaborative effort has made corneal transplantation so successful. Because of the availability of corneal tissue, surgery can be scheduled as an elective procedure at a time convenient for the patient and surgeon.
As with any type of surgery, there are risks associated with corneal transplant surgery. The most important risk is rejection of the transplant. Fortunately, the risk of rejection is small (5% to 10% for most conditions requiring transplantation). The rejection cannot develop during the first two months after surgery; however, it may occur at any time thereafter, even years later. The rejection involves the patient’s body becoming sensitized to the foreign corneal tissue and attacking the donor cornea with inflammation.
The symptoms of potential rejection can be grouped by the mnemonic RSVP:
R: Redness (unusual redness of the eye)
S: Sensitivity (increase in light sensitivity)
V: Vision (sudden change in vision clarity)
P: Pain (increase in eye pain)
If a rejection of the transplant is developing, the patient should contact the surgeon immediately. The treatment of a rejection involves the use of steroid eye drops and/or injection which is usually successful in reversing the rejection and stabilizing the cornea. However, the treatment must be instituted as soon as possible. If too much time has elapsed for the rejection episode or if the rejection is particularly severe, the cornea may become cloudy and the vision will remain blurred. If the transplant is rejected, surgery may be repeated and also has a high success rate for restoring sight.
Post operative care and Instructions
It is advised to wear protective glasses even in day and a shield at night in bed for the first 1 month after surgery to prevent accidental rubbing of the eye. Subsequently protective glasses may be worn in daytime in outdoors.
Consult the doctor immediately, if any increase in redness or pain or sudden decrease in vision as this may be a sign of serious infection in the eye.
Do not rub or put pressure on the eye and protect the eye from injury.
Use the eye drops as per the prescription and to open the eye drop bottle never use a pin / needle instead use the screw on the cap tight to open it.
Avoid rubbing the eye and sleeping on the operated side for 6 weeks
Avoid strenuous activities, lifting heavy objects for 6 months and avoid getting dust or sweat in your eyes.