Ringing
In a New Procedure
by Elvira
Maricic
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Alison,
a 38-year-old office assistant, only needs her glasses when
driving at night. She's mildly nearsighted and wishes she could
be rid of her glasses permanently. Because of her low level
of nearsightedness, she doesn't consider refractive surgery
an option, so until very recently she had been sentenced to
putting on her glasses every time she got in her car.
Relief
in sight
Fortunately
for Alison and others like her, in April of 1999 the Food
and Drug Administration approved the use of corneal implants
for those with myopia between -1 and -3 diopters. The implants
improve vision by altering the shape of the cornea, which
is the transparent tissue that covers the iris and pupil of
the eye.
The
corneal rings are actually plastic half-rings that are inserted
about 400 microns deep into the peripheral cornea, outside
the central optical zone, framing the cornea in two half circles
and flattening it to improve vision. The entire procedure
takes about 10 to 15 minutes, and most patients can return
to work the next day.
In
clinical trials by the FDA, most patients achieved 20/20 vision
or better, and 16 percent achieved 20/10 vision.
Side
effects can include a scratchy feeling in the eyes for about
48 hours, as well as some light sensitivity, and recovery
takes eight weeks. At approximately $2,400 per eye, the procedure
is similar in price to laser refractive surgery, and because
it is considered elective, it is not covered by insurance.
The
corneal rings were originally referred to as ICRs, which stands
for intracorneal rings, but now they go by the brand name
of Intacs. "When they were [FDA] approved, they were called
Intacts, but I think you'll still find a lot of doctors calling
them ICRs," notes Jack T. Holladay, MD, who is in private
practice with Houston Eye Associates.
"It's
the first refractive surgery technique I know of that not
only preserves but actually enhances the prolate shape of
the cornea," says Holladay. "The other advantage of the rings
is that they are removable, so if a patient is unhappy with
them, we can take [the rings] out and they're back to normal,"
he says.
There
are additional uses for corneal rings as well, notes Holladay.
"They are also useful for what we call an enhancement. Take
somebody that has come out of LASIK [laser assisted in situ
keratomileusis] undercorrected, but they don't have enough
tissue left to remove or to get them to where they should
be. The rings can be used to enhance that site without making
the tissue any thinner."
The
rings, however, are not for everyone. Those with nearsightedness
that is greater than 3 diopters are out of luck, as well as
patients with astigmatism.
The
learning curve
A
downside of the procedure is that since it is so new, surgeons
are still learning how to do it. "In the studies it showed
that as they're learning, sometimes they don't get the ring
in the right plane or the right level, but those are usually
learning techniques that go away as the surgeon gets better,"
Holladay explains.
He
expects physicians to be proficient at the surgery by the
end of this year. "So many people are getting trained and,
like anything else, they put courses on all around the country.
Within a year, most of the doctors that are doing refractive
surgery will be able to do this."
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