What is Keratoconus

Keratoconus comes from "kerato", meaning cornea, and "konos", meaning cone. Keratoconus is a condition where the normally spherical or round shape of the cornea becomes cone-shaped and subsequently causes blurred vision. The progression of this condition is usually slow and can stop at any stage from mild to severe. As keratoconus progresses, the cornea bulges and thins, becoming more conical. In some instances, scars may develop in the cornea.

What Causes Keratoconus?

Although this condition has been described for more than two centuries, the exact cause of this condition is still unknown. Several theories have been proposed. One theory suggests that this condition is genetic and that certain individuals are born with a predisposition. A second theory suggests that keratoconus is a degenerative process. Another theory suggests that keratoconus is related to other disease processes. Children with Down's Syndrome are at greater risk for developing this disease. Heredity probably plays a role in this disease as 13% of patients have family members with this condition.

Who Gets Keratoconus?

This condition has been estimated to occur in 1 in 2000 in the general population. The condition usually starts during the teen years. Geographic, cultural or social characteristics are not risk factors.

What are the Signs & Symptoms?

Initially, the symptoms of keratoconus may be blurred and distorted vision that requires frequent changes in your eyeglass prescription. Progressive thinning of the cornea, which can occur over a 5 to 10 year period before stabilizing, usually causes this process. Occasionally, a sudden clouding of the vision may occur in one eye, which can take several months to resolve. This event is called an "acute hydrops" and is caused by a sudden influx of fluid into the thinned cornea. This event often leaves behind a scar, further blurring the vision.

How is Keratoconus treated?

The overall goal in treating keratoconus is to correct the vision as best as possible. In mild cases, this may be done with eyeglasses. In most cases, however, contact lenses are required. In advanced cases, a corneal transplant may be necessary.

Contact Lenses

Contact lenses can be used to correct the nearsightedness and astigmatism caused by the thinning and bulging cornea. The lens type most commonly used is a rigid gas permeable lens (RGP). These are effective for treating keratoconus for a number of reasons:

• They correct the nearsightedness and astigmatism caused by keratoconus.
• They allow the cornea to breathe oxygen directly through the lens.
• They are easy to insert, remove and clean.
• They can be custom designed to fit the unique shape of the cornea.

Sometimes a combination of soft contact lenses and RGP lenses are used. As keratoconus progresses and the cornea become steeper, it can be challenging to achieve a good contact lens fit. Our skilled optometrists will work with you to provide you with the best-corrected vision.

Most patients with keratoconus can comfortably wear their contact lenses throughout the day and are able to carry on productive lives with minimal or no disruption of work and hobbies. In fact, many successful people have keratoconus, including athletes, actors, doctors, and business people. Most began wearing contact lenses when the condition was diagnosed, and the majority will continue to successfully wear contact lenses the rest of their life. Although contact lenses significantly improve vision, they are not a cure for keratoconus, nor will they alter the course of the condition.

Corneal Transplant

A corneal transplant is necessary in about 20% of keratoconus cases. In this surgery, the central cornea is removed and replaced by a donor cornea. Eye banks in major cities collect health corneas from recently deceased people and make them available for patients requiring transplants.

The success rate for corneal transplant surgery is 95%, but as with all operations, there are some risks and complications. If the transplant fails or is "rejected", another surgery may be required. Rarely, keratoconus can recur in the transplanted cornea. As such, surgery is reserved for cases where contact lenses are unable to improve the vision. Even after the surgery, contact lenses may be necessary to correct any residual corneal irregularity occasionally seen after transplant surgery.

For additional information, please go to the National Keratoconus Foundation website.