Introduction
The cornea is a transparent dome-shaped layer in the front of the eye that focuses light through the eye to help you see. For clear vision, the cornea must be healthy, clear and smooth. A damaged or scarred cornea will result in hazy or blurry vision. Corneal transplantation is a procedure to replace an unhealthy, damaged cornea with a healthy corneal transplant from a deceased donor.
Donors are people who offer their corneas after they die to those who require the same. Donated corneas are well tested in advance to ensure they are healthy.
Indications
The cornea may be damaged or diseased due to conditions such as:
- Keratoconus, where the cornea becomes thin and cone shaped
- Fuchs’ dystrophy, an abnormality of the inner layer of the cornea, called the endothelium
- Scarring due to infections or injuries
- Corneal damage due to previous eye surgery
Corneal transplantation is usually recommended when the cornea cannot be repaired or healed by other means.
Types of procedures
Depending on the condition of your cornea, your doctor may transplant the full thickness of the donor cornea, the outer and middle layers together or just the inner layer.
A full-thickness corneal transplant, also called a penetrating keratoplasty, is indicated when both the outer and inner layers of the cornea are found to be unhealthy. This type of transplant has a longer recovery period and it can take approximately a year for your vision to optimize. There is also a slightly increased risk of a full-thickness transplant being rejected.
A partial thickness corneal transplant or lamellar keratoplasty may be performed when the inner layer of the cornea is healthy. It involves transplantation of only the outer and middle layers of the cornea. Retaining the inner layer helps your body to accept the transplant better and recovery is quicker.
Certain conditions may damage the inner layer of your cornea and cause it to swell and affect vision. Endothelial keratoplasty is a procedure in which the inner layer of the cornea is replaced leaving the other layers intact.
Your doctor will determine the appropriate procedure for your condition.
Preparation
Before your operation, your doctor will discuss the procedure in detail. Healthy donor tissue is acquired and a date is set for the procedure. A complete medical examination is performed. Your doctor will discuss any regular medications you are on as you may have to stop certain medications before the procedure. Corneal transplantation is usually performed as an outpatient procedure, so you should have someone ready to drive you home.
Surgical procedure
During the procedure, you will receive eye drops and medication to help you relax. Local or general anesthesia is administered. A device is used that holds the eye open. Depending on the type of procedure, a portion of your cornea is removed and replaced with a matching section of donor tissue. The transplanted tissue is then stitched in place.
For an endothelial keratoplasty, an incision is made at the edge of the cornea and the inner layer of the cornea is removed. A healthy disc of donor tissue is then placed through the incision. An air bubble is used to position the transplant over the inner surface.
Other eye problems such as a cataract may also be addressed during the procedure.
After the procedure, an eye shield is placed over the eye to protect it. You will be monitored until you recover from anesthesia. Post-operative care instructions are given, and you will then be able to go home.
Post-operative care
You will have to return to your doctor the following day for a check-up and possibly to have stitches removed depending on how well you heal. Eye drops are prescribed which you should use exactly as directed. You will have some pain for which your doctor will recommend medication. An eye shield or eye glasses should be worn to protect the eye.
Risks and Complications
As with any surgery, corneal transplantation may be associated with certain complications including rejection of the transplant, infection, bleeding, glaucoma and detachment of the retina.
Summary
Corneal transplantation is an ideal option for those with poor vision due to a damaged or diseased cornea. The success of the transplant depends on various factors such as the type of procedure and the general health of your eyes. Most people experience significant improvement in vision for many years or even the rest of their lives.
