What is Keratoconus?

Keratoconus is a disorder of the anterior surface of the eye (the cornea). In simple terms, the cornea becomes thinner causing it to bulge from its normal round shape to a cone shape. This bulging interferes with a person's vision and can severely affect the way they see the world, making simple tasks like reading, watching TV or driving very difficult. The distortion caused by keratoconus has been compared to viewing a street sign through your car windshield during a driving rainstorm.

The progression of keratoconus is unpredictable, but generally the condition progresses slowly and can cease at any stage. While keratoconus interferes with the clarity of a person's sight it rarely causes blindness. In its early stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. As the disorder progresses, the degree of vision obtained through glasses becomes less acceptable and contact lenses often become the best method of correcting vision problems.

Most people can successfully manage their condition using special keratoconus contact lenses, however in a small number of cases where the cornea can no longer successfully be fitted with contact lenses, a corneal transplant may be needed.

Who Gets Keratoconus?

The actual incidence of keratoconus is estimated to occur in 1 to 5 persons per 1,000 in the general population. Keratoconus is generally first diagnosed in young people at puberty or in their late teens but can also be first diagnosed in people in their 40's or 50's. Keratoconus has no known geographic, cultural or social pattern, however its incidence seems to be higher in isolated populations. With continuing improvements to diagnostic equipment and eye care practitioner training, more cases of keratoconus are being diagnosed.

What Causes Keratoconus?

The characteristics of keratoconus have been known for at least 200 years, but the specific causes are still undetermined. Several theories have been proposed:

• One scientific theory is that keratoconus is genetic in origin. About 7% of patients have other family members with the disease.
• Another view holds that keratoconus is a degenerative condition perhaps linked to the altered balance between enzymes and inhibitors within the cornea.
• Keratoconus may also be secondary to some disease processes.
• A hypothesis has also been proposed that keratoconus may involve the endocrine system (hormones) since the condition is often diagnosed in young people at puberty or in their late teens.

While the exact cause of keratoconus has not yet been determined, research into keratoconus continues and new treatment options are continually under development.