The cornea is the transparent front part of the eye which covers iris, pupil and anterior chamber. It is a layer in front of the eye which helps to focus the light so that you can see clearly. If the cornea gets damaged, you have to replace with the healthy layer of tissues because when the light rays pass through the damaged cornea can get distorted and change your vision.
When all or part of the damaged or diseased cornea is removed and replaced by a healthy layer of tissues is called cornea transplant. Cornea transplant is also known as keratoplasty or corneal grafting which can bring back vision, lessen pain and improve the look of a damaged cornea. When the entire is replaced by a healthy cornea, it is called penetrating keratoplasty, and when a part of the cornea is replaced, it is known as lamellar keratoplasty. The new cornea comes from the people who donate the tissue when they die. The donor of the cornea should not have any disease which may affect the chance of the survival of the donated tissue or the health of the recipient. A donor can be of any age. Cornea transplant is recommended when medicine, cross-linking and conservative keratoconus surgery cannot heal the cornea anymore. Cornea transplant is helpful in several eye problems such as –
- Cornea scarring because of infection or injury
- Corneal ulcers because of infection
- Clouding, thinning or swelling of the cornea
- Problem caused by an eye operation
- inherited eye disease such as Fuchs’ dystrophy
When the cornea is damaged, it becomes less transparent and its shape change. So it prevents the light reaching to retina which causes the picture transmitted to the brain to be unclear or distorted.
The type of cornea transplant depends on which part of the cornea is damaged and how much is damaged. There are three types of cornea transplant-
- Penetrating Keratoplasty – it is a full thickness transplant.
- Deep Anterior Lamellar Keratoplasty- in this transplant outer and the middle layer of the cornea is replaced or reshaped.
- Endothelial Keratoplasty – in this transplant the deeper layer of the cornea is replaced.
Cornea transplant can be done by giving general anesthesia or local anesthesia. In general anesthesia the person is unconscious, and in local anesthesia, the area of surgery is numbed. The whole process of cornea transplant takes less than one hour, and you can leave the hospital on the same day or stay overnight, it depends on your condition. To keep the outer cornea on place stitches are required which usually stay in for more than 12 months. In an endothelial transplant, stitches are not required. It is held in place by an air bubble until a few days later when it naturally sticks to the deep layer of the cornea.
Cornea transplant surgery is like other organ transplant surgery. There is a risk of complication in cornea transplant such as transplanted cornea can be rejected by the body, infection and other vision problems can occur. According to data around 95% of full thickness cornea transplants have low risk and lasts for at least ten years.