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Keratoconus
This disorder--a progressive
thinning of the cornea--is the most
common corneal dystrophy in the
U.S., affecting one in every 2000
Americans. It is more prevalent in
teenagers and adults in their 20s.
Keratoconus arises when the middle
of the cornea thins and gradually
bulges outward, forming a rounded
cone shape. This abnormal curvature
changes the cornea's refractive
power, producing moderate to severe
distortion (astigmatism) and
blurriness (nearsightedness) of
vision. Keratoconus may also cause
swelling and a sight-impairing
scarring of the tissue.
Studies indicate that keratoconus
stems from one of several possible
causes:
An inherited corneal abnormality.
About seven percent of those with
the condition have a family history
of keratoconus.
An eye injury, i.e., excessive eye
rubbing or wearing hard contact
lenses for many years.
Certain eye diseases, such as
retinitis pigmentosa, retinopathy of
prematurity, and vernal
keratoconjunctivitis.
Systemic diseases, such as Leber's
congenital amaurosis, Ehlers-Danlos
syndrome, Down syndrome, and
osteogenesis imperfecta.
Keratoconus usually affects both
eyes. At first, people can correct
their vision with eyeglasses. But as
the astigmatism worsens, they must
rely on specially fitted contact
lenses to reduce the distortion and
provide better vision. Although
finding a comfortable contact lens
can be an extremely frustrating and
difficult process, it is crucial
because a poorly fitting lens could
further damage the cornea and make
wearing a contact lens intolerable.
In most cases, the cornea will
stabilize after a few years without
ever causing severe vision problems.
But in about 10 to 20 percent of
people with keratoconus, the cornea
will eventually become too scarred
or will not tolerate a contact lens.
If either of these problems occur, a
corneal transplant may be needed.
This operation is successful in more
than 90 percent of those with
advanced keratoconus. Several
studies have also reported that 80
percent or more of these patients
have 20/40 vision or better after
the operation.
The National Eye Institute is
conducting a natural history
study--called the Collaborative
Longitudinal Evaluation of
Keratoconus Study--to identify
factors that influence the severity
and progression of keratoconus.
Content Courtesy : www.nei.nih.gov
Note : Information herein is
provided for informational purposes
only and is not a substitute for
professional medical advice. You
should not use this information for
diagnosing or treating a medical or
health condition. If you have or
suspect you have a medical problem,
promptly contact your professional
healthcare provider. Please consult
your healthcare provider before
beginning any course of
supplementation or treatment.
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