The cornea is the clear, dome shaped window of the eye. It has two primary functions. It protects the delicate inner structures of the eye and also refracts (focuses) light as it enters the eye and passes through the lens. It is avascular (without blood vessels) and therefore the only clear, transparent tissue in the body uniquely adapted for light to pass through. There are a number of conditions that can threaten the health of the cornea resulting in a loss of vision. The most common types of corneal problems are infections, diseases, degenerations, and trauma.
Infections of the cornea can be caused by bacteria, viruses (such as the herpes virus), funguses, or parasites. Infections of the cornea are typically characterized by redness, pain, mucus or teary discharge, and decreased vision. They require immediate attention.
Diseases of the cornea range from ocular involvement from systemic diseases such as rheumatoid arthritis to specific genetic and acquired conditions that affect the cornea. Degenerations are conditions that occur with the aging of the eye such as pterygia, keratoconus, and various chemical deposits in the cornea.
Trauma to the cornea can result in lacerations, scarring, and corneal swelling (edema) that reduce vision. All of the above problems compromise vision by damaging the cornea and altering the quality of life. Consultation with a corneal specialist often times can help in the recovery from these types of problems and restoration of more normal vision.