Keratoplasty, or corneal transplantation, is performed when the curvature of the cornea (the transparent covering on the eye's anterior wall) is too steep or too flat to be treated with other methods, when extensive damage has occurred due to injury or disease, or when a tumor is present. Traditional keratoplasty is a procedure that removes and replaces the cornea with donor tissue. In recent years, less invasive procedures, which remove only selected portions of corneal tissue, have been refined and offer quicker and safer visual rehabilitation.
Reasons for Cornea Transplantation
Conditions that may require a corneal transplantation include:
- Corneal scarring
- Inherited corneal disorders, like Fuchs' dystrophy
- Infections of the eye
- External tumor or pterygia
- Irreversible cornea edema
- Corneal ulceration or erosion
- Corneal thinning or perforation
The most common reason for performing a keratoplasty is to improve diminished vision. Less commonly, the surgery is performed to treat a chronic corneal infection.
Types of Cornea Transplantation Procedures
Keratoplasty is a relatively low-risk surgical procedure. It is the most common type of transplant surgery currently performed and has the highest rate of success. There are several different corneal transplant methods available to help restore vision in patients with corneal problems.
Penetrating keratoplasty is the traditional method used for corneal transplantation where the central two-thirds of the damaged cornea is surgically removed and replaced with a healthy cornea from a human donor.
Deep Anterior Lamellar Keratoplasty
Deep anterior lamellar keratoplasty, also known as DALK, removes the middle and outer layers of the cornea, while preserving the healthy, well-functioning inner layers, known as Descemet's membrane and the endothelium. Retaining these inner layers can reduce the risk of some intraoperative and postoperative surgical complications.
Endothelial keratoplasty, of which there are several types (DSAEK, DSEK and DMEK), is a surgical procedure that removes the abnormal inner lining of the cornea, known as the endothelium. Endothelial keratoplasty requires much smaller incisions than a penetrating keratoplasty, resulting in fewer risks and a shorter recovery time.
Corneal transplants are usually performed with patients under local anesthesia. In every type of transplantation there is a risk of graft rejection or failure of the donor tissue to heal and function properly within the recipient. However, in the less invasive procedures others risks may be reduced and the period of visual recovery may be shortened.