WHAT IS THE CORNEA?
The cornea is the clear dome-shaped part of the eye in front of the iris and pupil.
The cornea works in three ways:
- It shields the eyes from undesirable elements like germs and dirt with cooperation from the other parts of the eye.
- It focuses the entry of light into the eye.
- It filters out UV rays from the sun.
When the cornea becomes damaged, either by disease or injury, light cannot properly enter the eye and vision is damaged or destroyed.
Corneal transplantation, also known as corneal grafting or penetrating keratoplasty, is a surgical procedure where a damaged or diseased cornea is replaced by donated corneal tissue that has been removed from a recently deceased individual having no known diseases which might affect the viability of the donated tissue. The surgical procedure is performed by an ophthalmologist, a medical doctor who specializes in eyes, and can often be done on an outpatient basis.
Donor corneas are recovered during a surgical procedure performed with sensitivity and respect by highly trained medical staff. If a person has agreed to be an eye and/or cornea donor or next of kin consents to donation at the time of death, an Eye Bank Recovery Technician will be sent to the location of the donor. Donor corneas must be removed within several hours of death to remain viable for transplant. All tissue recoveries occur in a sterile environment. Donated eyes and corneas are typically removed at a funeral home, hospital setting or the Medical Examiner’s Office. The Eye Bank employs many layers of screening and evaluation to identify medically suitable donors. Our commitment to tissue safety begins with donor screening, including a review of medical records, a medical/social history interview, examination of the body, and a review of autopsy results when applicable. An extensive battery of blood tests is also performed to rule out a variety of potentially harmful infections. We eliminate those with any health related high risk factors that would make the donated tissue unsuitable for transplantation. Once the tissue is cleared for transplant, it is placed with an ophthalmologist for surgery.
On the day of the surgery, the patient arrives at a hospital or an outpatient surgery center where the procedure will be performed. The patient is given a brief physical examination by the surgical team and is taken to the Operating Room (OR). In the OR, the patient lies down on an operating table and is given anesthesia.
With anesthesia induced, the surgical team prepares the eye to be operated on and drapes the face around the eye. An eyelid speculum is placed to keep the lids open and lubrication is placed on the eye to prevent drying. The surgeon removes the patient’s cornea and the donor cornea is fastened to the patient’s eye with stitches. The surgeon reforms the anterior chamber (the fluid-filled space inside the eye between the iris and the cornea’s innermost surface, the endothelium) by injecting a sterile solution and then testing to make sure it is watertight. Antibiotic eye drops are placed, the eye is patched, and the patient is taken to a recovery area while the effects of the anesthesia wear off. The patient typically goes home following this and sees the doctor the following day for the first post operative appointment.
New Techniques Bring Better Vision
In recent years, new cornea transplant procedures have been developed that replace only the damaged layer of cells instead of the entire thickness of the cornea in some patients. These surgical techniques, known as lamellar cornea transplants DSAEK (Descemet’s Stripping Automated Endothelial Keratoplasty) or DMEK (Descemet’s Membrane Endothelial Keratoplasty) offer better patient outcomes, according to surgeons, and faster healing times.
In a DSEK procedure, damaged cells are removed from the recipient’s cornea, then a layer of the donated cornea is folded over and slipped into place through a small incision.
High Success Rate
Corneal transplants are the most common human transplant and enjoy a 95% success rate. About 40,000 people in the United States receive corneal transplants every year. Corneal transplant is only possible through cornea donation. There is currently no substitute for human corneal tissue. Without the generosity of cornea donors, many thousands would be left without sight every year.