Corneal transplantation is a surgical procedure in which a surgeon exchanges a damaged or diseased cornea with a healthy one. The cornea is the transparent covering of the front part of the eye. It is made of cells which protect the eye and give clear vision.
Should the cornea end up swollen, damaged or scarred, light may not focus appropriately into the eye. This may result in glare or a blurry vision. The eye doctor may recommend a corneal transplant to remedy the situation.
Patients receive healthy corneas from human donors who had consented to donate before death. The corneas will undergo a rigorous check to ensure they are safe for use.
The doctor will recommend a corneal transplant in the event of the following:
- Keratoconus, the thinning of the cornea resulting in a shape of a cone instead of a dome
- Fuchs’ dystrophy, a condition that causes the cornea to swell
- Eye injuries and infections that can lead to corneal scarring
- Previous eye or corneal surgery which damaged the cornea
Types of surgery
- Penetrating keratoplasty (PK) (full thickness corneal transplant). PK is the preferred treatment if both the front and inner layers of the cornea have suffered damage. The entire cornea is replaced. PK patients may take up to one year to experience complete vision and the risk of organ rejection is higher with PK.
- Deep anterior lamellar keratoplasty (DALK) (partial thickness corneal transplant). Only the middle and front layers of the cornea are replaced. The endothelial layer is retained. DALK is used for the treatment of keratoconus. Unlike PK, it takes a shorter time to heal and the risk of corneal rejection is significantly lower.
- Endothelial keratoplasty (partial transplant) replaces only the endothelium. Some types of endothelial keratoplasty include Descemet’s stripping (automated) endothelial keratoplasty (DSAEK or DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK). Only the Descemet’s membrane is replaced leading to quicker recovery and a lesser risk of rejection.
The purpose of a corneal transplantation is to correct vision. The patient has his diseased, scarred, damaged or swollen cornea partially or fully removed. A healthy cornea then takes its place.
Preparation & expectation before Surgery
The following may take place as an individual prepares for surgery:
- A discussion with an ophthalmologist to determine if the patient needs the transplant. The surgeon will take the medical history including details like allergies
- A date is picked depending on the availability of tissue
- One may need to stop using blood thinners
- One must avoid jewelry, makeup, creams, lotions and so on
- One may need to make arrangements for transport back home
- One needs to disclose any medications they may be using
- One may need to undergo some tests to ensure fitness before surgery
In this outpatient procedure, the medical assistant will put eye drops in the patient’s eye and give other medicines to help the patient relax. General or local anesthesia will also be administered to prevent pain. Anesthesia keeps the patient from seeing anything during the procedure. The surgeon will do the following:
- Use a speculum to keep the eyelids open.
- Perform a PK, DALK or endothelial keratoplasty depending on the specific need. After replacing the cornea, the surgeon then stitches it into place. In the case of endothelial keratoplasty, he/she puts an air bubble in the eye to facilitate proper healing.
- Repair other eye problems like cataracts during the surgery in some cases.
- Put a shield over the eye for protection. The patient needs to wear an eye patch for 1 to 4 days.
- Check that the patient has recovered from the anesthesia before being released to go home.
- Give the patient some instructions on care while at home.
After care, recovery, results
The patient needs to return to the surgeon the following day for a check-up. During this time, the surgeon may or may not remove the stitches. Removal of stitches depends on the eye’s health, the stitches used and how quickly the patient is healing.
The following are some of the things the patient is expected to do for home care:
- Take an over-the-counter medication for pain
- Avoid rubbing the eye or putting pressure on it
- Put on an eye shield or glasses to protect the eye
- Follow the surgeon's instructions correctly on use of eye drops
It may take one year or more for one to recover from a corneal transplant completely. The patient may need glasses or lenses for better visual outcomes. After complete healing, some patients may have laser surgery to correct astigmatism, hyperopia or myopia. Severe irreversible rejection called graft failure is very rare because the cornea does not need blood supply. Those whose transplants are unsuccessful can do keratoprosthesis, that is, use of an artificial cornea.
Since rejections can occur years after surgery, one needs to see the doctor annually.
Risks & complications
Three out of ten people experience organ rejection. Signs of rejection may include pain in the eye, being extra sensitive to light, hazy vision and a red eye. The surgeon can stop the rejection using steroid eye drops.
Other eye problems such as bleeding, infection, retinal detachment, cataract and glaucoma can arise. Astigmatism, macular degeneration or diabetic retinopathy could also result. There may also be scarring of the eye, swelling of the cornea and loss of vision.
Some patients might have a repeat corneal transplant if the first one failed due to rejection or some other problem. However, the likelihood of rejection in a repeat transplantation is higher.