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Orthokeratology:
Reshaping Your Eyes with
Contact Lenses
When you sleep, you wear
special contact lenses that
gently reshape the surface
of your eye, so you can see
clearly even after you
remove the lenses. The
effect is temporary -
generally enough to get you
through a day or so, but you
must wear the special lenses
each night.Reshaping the
cornea with contact lenses
to improve vision isn't new.
Orthokeratology has been
practiced by some eye
doctors for decades.
However, in the past ortho-k
produced mixed results and
wasn't FDA-approved for
overnight wear, so the
procedure had limited
appeal.
Then in June 2002, the FDA
granted overnight wear
approval to a type of
corneal reshaping called
Corneal Refractive Therapy
(CRT). More overnight
ortho-k approvals followed.
Myopia (nearsightedness) is
caused by light coming into
the eye in such a way that
it doesn't focus properly on
the retina. Typically, this
problem is corrected by
using eyeglasses or regular
contact lenses to re-focus
the light rays.
A similar result can be
achieved by reshaping your
cornea. LASIK is a surgical
way to do this. Ortho-k
contact lenses flatten your
cornea without surgery,
enabling light to focus
properly on your retina,
resulting in better vision.
Orthokeratology is for
people of any age who are
nearsighted. The FDA has
approved CRT for people with
up to six diopters of myopia
(-6.00 on your
prescription); the VST
approval is for up to five
diopters. Astigmatism can
also be treated: up to -1.75
with CRT, and -1.50 with
VST. Many doctors believe
the best candidates are
people who have low amounts
of myopia, about four
diopters or less.
The procedures can be
performed on practically
anyone of any age, as long
as their eyes are healthy.
Ortho-k holds particular
appeal for people who
participate in sports, or
who work in dusty, dirty
environments that can cause
problems for regular contact
lenses.
Because ortho-k offers
similar benefits to LASIK,
it's also appealing to
adolescents and teens, who
are not eligible for LASIK.
However, there are some
concerns about corneal
infections in young people
who have used ortho-k, so
it's wise to pursue this
with an eye care
practitioner who is
experienced in treating this
age group.
Eye care professionals
usually aim for 20/20
vision, but 20/40 vision
(the legal minimum for
driving in most of the
United States) is typically
considered acceptable. In
the FDA clinical study for
approval of CRT, 93 percent
of patients achieved 20/32
vision or better, and 67
percent achieved 20/20 or
better. In the clinical
study for FDA approval of
one VST design, about 95
percent achieved 20/40 or
better, and 73 percent
achieved 20/20 or better.
Both studies followed
patients over at least a
nine-month period.
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