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Disorders and Diseases of the Eye: Keratoconus
Disorders of the Eye:
Diseases of the Eye:
Keratoconus is a vision disorder that occurs when the normally round cornea (the front part of the
eye) becomes thin and irregular (cone) shaped. This abnormal shape prevents the light
entering the eye from being focused correctly on the retina and causes distortion of
vision.
In its earliest stages, keratoconus
causes slight blurring and distortion of vision and increased sensitivity to glare and
light. These symptoms usually appear in the late teens to late twenties. Keratoconus may
progress for 10-20 years and then slow in its progression. Each eye may be affected
differently. As keratoconus progresses, the cornea bulges more and vision may become more
distorted. In a small number of cases, the cornea will swell and cause a sudden and
significant decrease in vision. The swelling occurs when the strain of the cornea's
protruding cone-like shape causes a tiny crack to develop. The swelling may last for weeks
or months as the crack heals and is gradually replaced by scar tissue.
Eyeglasses or soft contact lenses may be used to correct
the mild nearsightedness and astigmatism that is caused by the early stages for
keratoconus. As the disorder progresses and the cornea continues to thin and change shape,
rigid gas permeable contact lenses can be prescribed to correct vision more adequately.
The contact lenses must be carefully fitted, and frequent checkups and lens changes may be
needed to achieve and maintain good vision.
In a few cases, a corneal transplant is necessary.
However, even after a corneal transplant, eyeglasses or contact lenses are often still
needed to correct vision.
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