cornea

Transparent front section of the vertebrate eye. The cornea is curved and behaves as a fixed lens, so that light entering the eye is partly focused before it reaches the lens.

There are no blood vessels in the cornea and it relies on the fluid in the front chamber of the eye for nourishment. Further protection for the eye is provided by the conjunctiva. In humans, diseased or opaque parts may be replaced by grafts of corneal tissue from a donor.

Australian researchers developed the world's first artificial cornea in 1998. In 1999 North American researchers succeeded in growing corneas in the laboratory, which have been used in medical and cosmetic research. By 2005, artificial corneas (also known as keratoprosthesis) had been implanted into hundreds of patients who were not eligible for transplants of human donor corneas.