The cornea is the clear dome-shaped “window” in the front of the eye. Behind this clear window lies the iris, or colored portion of the eye. The cornea serves two purposes: (1). It forms the front part of the eye’s outer wall or shell and thus protects the inside of the eye. (2). With its curved shape, the cornea acts like a camera lens to transmit light and focus images on the retina at the back of the eye. There are several layers of the cornea (see diagram)
Following disease, infection or injury, the cornea may become weakened, cloudy, or irregular in shape. If medicines, contact lenses, or other treatments are ineffective, in some cases the damaged cornea can be replaced with a healthy cornea from a deceased person. This replacement procedure is called a corneal transplant or penetrating keratoplasty, oftentimes called a PKP for short.
Although attempts at corneal transplantation were made 100 years ago, the first consistent success was achieved by Dr. Ramon Castroviejo and Dr. Max Fine in the 1950’s. Corneal transplant is the most successful of all tissue transplants. An estimated 40,000 such operations are performed in the United States each year. Dr.Liu is a Board-Certified ophthalmologist and he’s also a corneal transplant and external disease specialist.
The Donor Tissue
Corneal tissue for transplantation comes from an Eye Bank. The process begins when someone has been generous enough to donate his or her eyes following their death. The Eye Bank carefully screens the donor
cornea to ensure it meets the National Eye Bank Association quality standards. The color of the donor eye is irrelevant, since only the transparent dome in the front of the patient’s eye is replaced, and not the colored iris behind it. Similarly, tissue typing is not necessary since their are no blood vessels in the normal healthy cornea. When healthy tissue becomes available, the central Eye Banks enter the information into a nationwide computer network. The corneal tissue is then sent by airplane to the site where it is needed after careful selection and screening by your surgeon. The tissue can be stored for several days in a nutrient fluid before use in the case of a PKP.