What is Keratoconus?

Copyright 1997 medhelp.org
Keratoconus (KC) is a non-inflammatory condition of the cornea in which there is progressive central thinning of the cornea changing it from dome-shaped to cone-shaped. Keratoconus comes from the Greek word meaning conical cornea. The cornea is the clear windshield of the eye and is responsible for refracting most of the light coming into the eye. Therefore, abnormalities of the cornea can greatly affect the way we see the world.

Keratoconus is not a blinding disorder, but does result in increasing near-sightedness (things far away are out of focus) and irregular astigmatism (things look tilted) that can significantly distort your vision. It is almost always bilateral (affecting both eyes). It is a slowly progressive disorder, taking years to develop, and may halt at any stage from mild to severe.

Keratoconus has been well described since the mid-nineteenth century, however, the underlying reason for its development remains obscure. Keratoconus is currently the topic of much research. Some cases of KC have a hereditary component and studies indicate that about 8% of patients have affected relatives. However, most cases appear to be sporadic. It has been suggested that there is less than a 1 in 10 chance of having a child with some degree of keratoconus if one of the parents have KC without a family history. The actual incidence of KC is uncertain, large studies estimate 50 to 230 per 100,000. It occurs in all ethnic groups and has a slight female preponderance.

Keratoconus usually has its onset in puberty with progression over a 10 to 20 year period. This rate of progression is variable as well as the severity, ranging from mild astigmatism to severe corneal thinning, protrusion, and scarring. Keratoconus has been associated with other medical disorders including atopic disease, Down's syndrome, Ehlers-Danlos syndrome, Marfan's syndrome, craniofacial dysostosis and osteogenesis imperfecta. Even excessive eye rubbing has been implicated in this disease.

Patients with KC initially notice visual blurring and distortion. This may be accompanied by photophobia (light sensitivity) and glare. Patients may note the need for frequent changes in their glasses. In the advanced stages, there may be a precipitous drop in vision due to clouding of the cornea, referred to as acute corneal hydrops. This condition usually resolves over weeks to months but is often followed by central corneal scarring.

Treatment of keratoconus depends on the severity of the condition. Initially, eyeglasses are often successful in correcting the myopia (near sightedness) and astigmatism; however, as the disease advances vision is not adequately corrected and requires rigid contact lenses to aid in flattening the corneal surface and providing optimal visual correction. Contact lens fitting can be difficult in patients with KC requiring frequent visits and lens changes but recent advances in the contact lens industry as provided more fitting options. Lastly, when good vision can no longer be attained with contact lenses or intolerance to the contact lens develops, corneal transplantation is recommended. This is only necessary in about 10% of patients with KC and carries a success rate of greater than 90%, one of the highest for corneal transplantation. Although this procedure replaces the thinned central portion of the corneal, eyeglasses and contact lenses are often required for maximal visual acuity.

How do I get more information? You are not alone. Many people suffer from this disorder. The National Keratoconus Foundation is a non-profit organization dedicated to research in keratoconus and providing patient information and support. For more information contact:

National Keratoconus Foundation
Davis Building, Suite 509
8700 Beverly Boulevard
Los Angeles, CA 90048

(310) 855-6455 Office
(800) 521-2524 Hotline
(310) 652-8411 Fax
e-mail: nkcf@csmc.edu

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