What is the Cornea?
THE CORNEA
The cornea is the clear front window of the eye. It transmits light to the interior of the eye allowing us to see clearly. Corneal injury, disease, or hereditary conditions can cause clouding, distortion, and scarring. Corneal clouding, much like frost on a glass windowpane, blocks the clear passage of light to the back of the eye, reducing sight sometimes even to the point of blindness. In addition, corneal injury and disease can be painful, sometimes the most intense pain we can experience.
CAUSES OF CORNEAL INJURY
Knives, pencils, and other sharp objects can cause severe injury to the cornea. Fireworks, exploding batteries, and toxic chemicals, especially alkalis, can also result in severe scarring of the cornea. In fact, protection of the cornea is the reason emergency washing of the eye is absolutely necessary when the eye is exposed to toxic chemicals. Most corneal injuries are preventable with protective glasses and proper precautions when dealing with hazardous substances.
CAUSES OF CORNEAL DISEASE AND DEGENERATION
Infections, whether bacterial , fungal, or viral are frequent causes of severe corneal damage and ulceration. Abnormal steepening of the cornea (keratoconus), degeneration occasionally following cataract surgery (corneal edema and swelling), and some aging processes can also affect the clarity and health of the cornea.
CORNEAL TRANSPLANTS
If the cornea becomes cloudy, the only way to restore sight is to replace or transplant the cornea. Corneal transplantation (keratoplasty) is the most successful of all tissue transplants with an overall success rate greater than 90%. The success rate depends on the cause of the corneal clouding.
For example, corneal transplants for degeneration following cataract surgery and those for keratoconus both have high success rates, while corneal transplants for chemical burns have lower success rates.
Corneal tissue for transplants comes from an eye bank. The process begins at the death of someone who has been generous enough to be a donor. Surgeons register their transplant surgery dates with the Lions Eye Bank of Wisconsin. At the appropriate time, Lions Eye Bank of Wisconsin staff contact the surgeon. The operation consists of a transfer of the clear central part of the cornea from the donor's eye to the patient's eye. Soon after the operation, the patient can walk about and resume activity.
AFTER SURGERY
Return of best vision after corneal surgery may take up to a year after the operation, depending on the rate of healing and the health of the rest of the eye. As in any kind of transplant, rejection of the donated tissue can take place. The major signs of rejection are redness of the eye or worsening of vision. If these occur, prompt return to the ophthalmologist is necessary even if it is years after the original procedure.
REGULAR MEDICAL EYE EXAMINATIONS ARE IMPORTANT FOR EVERYONE
Eye disease can strike at any age. Many eye diseases do not cause symptoms until the disease has done damage. Since most blindness is preventable if diagnosed and treated early, regular medical examinations by an ophthalmologist are very important. Why an ophthalmologist? Because only an ophthalmologist (MD) can provide total care for your eyes: medical, surgical, and optical.