The cornea is the clear front window of the eye. It is normally round and smooth. Keratoconus is a disease in which the cornea thins and begins to bulge into a cone-like shape. Keratoconus literally means a cone-shaped cornea. This abnormal shape can cause serious distortion of vision.

Keratoconus usually affects both eyes but can be asymmetric. It often appears in the late teens or early twenties and is a progressive condition. As the cornea becomes steeper and more irregular in shape, nearsightedness and irregular astigmatism develop.

The cause of keratoconus is still unclear. Factors that might be associated with this condition include a genetic predisposition, ultraviolet rays, contact lens wear and excessive eye rubbing.

The treatment of keraotocunus depends on the severity of the condition. In mild cases, eyeglasses or contact lenses can be used. As the disease progresses and the cornea becomes more irregular, hard or custom made contact lenses are required to reshape the cornea.

In patients with severe keratoconus that can no longer obtain functional vision with contact lenses, surgical procedures are needed to restore vision.

The of these procedures involves the placement of corneal inserts known as Intacs. Intacts are tiny plastic inserts that can flatten the cornea and delay the need for a corneal transplant.

Corneal transplants are indicated for patients in whom other therapies no longer provide acceptable vision. It is estimated that only 20% of people with keratoconus will require corneal transplant surgery. Even after a transplant, most patients will likely need glasses or contact lenses for clear vision.

A new procedure known as collagen cross-linking with riboflavin is in early clinical trials in United States. Ultraviolet light is used to strengthen corneal tissue to halt or reduce bulging. Early results have been promising and this procedure might reduce progression of the disease and the need for corneal transplants in the future.