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Albuquerque, NM – The FDA approved a
wavefront-guided LASIK procedure (CustomVue, VISX/AMO)
for treating mixed astigmatism on March 22.
This approval allows for WaveScan diagnosis and CustomVue
treatment of this patient population. CustomVue is presently
the only procedure approved in the United States for the
treatment of myopia, hyperopia, and mixed astigmatism,
according to the company.
Stephen Coleman, MD, was a principal
investigator in the mixed astigmatism trial as well as
the previous trials for myopia and hyperopia.
"The results of the treatment of low myopia were, as expected,
quite excellent," said Dr. Coleman, who is in private practice
in Albuquerque.
"I've been looking forward to the appoval for mixed astigmatism
primarily because I saw firsthand the impressive results
in my study patients and want to implement this software
in my private practice," Dr. Coleman said. "This procedure
is very powerful and sophisticated. It provices a very
complex laser ablation compared with that used for patients
with simple myopia or hyperopia. The mixed astigmatism
procedure flattens and steepens the cornea simultaneously.
"These patients have a less common ocular problem when
you look across a broad range of prescriptions and because
of that it can be difficult for them to achieve good correctable
vision with contacts or glasses," Dr. Coleman continued.
"Most importantly, these patients talk about quality of
vision issues preoperatively to a greater extent than patients
with myopia."
He added that patients with mixed astigmatism comment
frequently that their quality of vision improves after
having undergone a CustomVue procedure.
"This is one of the best things an ophthalmologist can
hear," Dr. Coleman said. "Often patients' uncorrected vision
pre-operatively is not particulary bad, which is characteristic
of mixed astigmatism. Their vision improves not only quantitatively
but, perhaps more importantly qualitatively. These are
happy patients."
Because the results of the trial of CutomVue for mixed
astigmatism proved to be so good, up until this commercial
FDA approval Dr. Coleman has advised that many of his patients
wait to be treated with the CustomVue software.
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image to enlarge |
All patients in the mixed astigmatism trial underwent
the procedure using the VISX STAR S4 IR excimer laser system
and the WaveScan WaveFront System. According to the manufacturer,
the procedure is approved to reduce or eliminate naturally
occurring mixed astigmatism when the magnitude of cylinder
(from 1 to 5 D) is greater than the magnitude of sphere
and the cylinder and sphere have opposite signs.
The trial included 86 eyes of 44 subjects and the mean
age was 41 ± 11 years. At the 3-month follow-up
visit, 62% of eyes were 20/20 or better and 95% were 20/40
or better. Also at 3 months, 78% of eyes were within ±0.50
D of intended MRSE (mean refactive spherical equivalent)
and regarding higher-order analysis, 100% of eyes had either
a decrease or a change of less than or equal to 0.10-µm
root mean square.
Another point that Dr. Coleman emphasized was the prostoperative
topography, which he described as beautiful.
"These patients have an expanded optical zone," he said.
"When comparing the postoperative topography from a convential
mixed astigmatism procefure with that from a wavefront-guided
procedure, the wavefront-guided topography is quite impressive.
"If a surgeon were to compare the two, he or she might
get the sense that the person who underwent the wavefront-guided
procedure was seeing better than the one with mixed astigmatism
who underwent the conventional procedure," Dr. Coleman
said.
Heather Ready, director of global marketing for VISX,
commented on the new opportunity provided by the approval
of CustomVue for both patients and surgeons.
"The approval of CustomVue to treat mixed astigmatism
allows us to provide the broadest range of treatments for
anyone with astigmatism, whether it is mixed astigmatism,
astigmatism associated with myopia, or astigmatism associated
with hyperopia," she said. "This gives surgeons more flexibility
to treat a broader array of patients. Regarding mixed astigmatism,
specifically, the surgeons are very excited about the approval
because these patients' vision is very difficult to correct
with contacts or glasses. This gives surgeons a viable
option to provide these patients with better-quality vision
than they could get otherwise."
Ready noted that the next thrust will be iris registration,
which just received approval and registers the wavefront
map image with the image under the laser. This technology
will ensure even more precise placement of treatment on
the eye.
Approval to use CustomVue for high myopia is expected
later in 2005. Back to Top
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