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Understanding Keratoconus
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Keratoconus is a disorder of the eye. The word is formed from the two Greek words "karato", meaning cornea, and "konos", meaning cone. Keratoconus is also known as conical cornea. You will often see it abbreviated as KC.
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In simplest terms, keratoconus causes a
bulgi ng of the cornea from its normal round shape to a cone shape. This significantly interferes with a person's vision. What the normal eye sees as a sharp and clear image, the keratoconic eye sees as blurry and
distorted. Some people describe keratoconus as looking at a street sign through a car windshield during a driving rain.
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The progression of keratoconus is generally slow, and it can stop at any stage, from mild to severe. As keratoconus progresses, the cornea continues to bulge and thin. It can also form scar tissue which further impairs vision. While KC interferes with
the clarity of a person's sight, it rarely causes blindness
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The characteristics of KC have been known for at least 200 years, but the specific causes are still undetermined. Several theories have been proposed. One scientific view is that KC is genetic in origin. About 7% of patients have other family members with the disease. Another view holds that KC represents a degenerative
condition. A third theory suggests that KC is secondary to some disease process. There is even a hypothesis that suggests KC may involve the endocrine system. While theories are many, research into the causes of keratoconus continues.
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The actual incidence of KC is not known. It is estimated to occur in 1 out of every 2000 people in the general population. The disease usually shows up in young people at puberty or late teen years. There is no significant geographical, cultural, or social pattern to its distribution.
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The first indication of KC is a blurring and distortion of vision.
In its early stages, this may be corrected with glasses that require frequent changes in the astigmatism correction. The cornea continues to thin slowly for 5 to 10 years, and then it tends to stop. Occasionally, KC is a rapidly progressive disease. In the advanced stage, the patient may experience a sudden clouding of vision
in one eye. It will clear over a period of weeks or months. This condition is known as acute
hydrops. It is due to the sudden infusion of fluid into the stretched cornea. In advanced cases, superficial scars form at the apex of the corneal bulge.
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As keratoconus advances, rigid gas permeable (RGP) contact lenses are the only way to correct vision adequately. Most of the time, this is a permanent remedy. Because of the progression of the disease, it is important that lenses are fitted with great care. Most KC patients need frequent checkups and lens changes to maintain
good vision and comfort.
It is encouraging that new rigid gas permeable contact lenses are constantly being developed to manage KC. The Dyna Z Intra-Limbal design is just one example. Its complex lens geometry takes into account the conical shape in the cornea. Because of it, the entire lens fits better over the eye and provides outstanding patient
comfort and optimum visual acuity.
In about 10% of KC cases, a corneal transplant becomes necessary. This is a common and very successful operation for those patients who need it. However, even with surgery, glasses or contact lenses are usually needed for proper vision correction.
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