| The cornea is a dime-sized clear tissue covering the front of the eye. Light rays pass through the cornea and then through the lens. The lens forms an image on the retina in the back of the eye where the optic nerve is located. Sight is controlled by the optic nerve, the only nerve of vision. This nerve activates the retina to pick up the image in view. If the cornea is cloudy or scarred from an eye injury or disease, vision becomes blurred. Scar tissue and other disorders can block light rays and prevent normal vision. The effect has been described by many patients as somewhat like looking through rippled glass. Fortunately, the clouded cornea can be removed and replaced by clear, healthy tissue from a generous eye donor. A person may obtain a corneal transplant through the request of a qualified eye surgeon (Ophthalmologist). First, the cloudy tissue is removed with a cylindrical cutting instrument called a trephine. The same trephine is used to cut out the donor cornea so that the shapes are identical. Then, the clear donor cornea is sewn into place. If the graft is successful, light rays will once again be focused onto the retina. Optical signals may then be channeled to the brain via the optic nerve so that normal vision occurs. This type of surgery has restored sight and changed the lives of thousands from children, to senior citizens to those in the prime of life. |
