October 13, 2005
IntraLase Laser Flap Achieved a 30%
Reduction in Standard Deviation Versus the B&L XP Bladed Microkeratome
IRVINE, Calif., Oct. 13 /PRNewswire-FirstCall/ -- IntraLase Corp.
(Nasdaq: ILSE) today commented on recent claims made in a head-to-head
study concerning the comparative outcomes of Bausch & Lomb's
bladed microkeratome device versus IntraLase's Femtosecond (FS)
laser instrument. A Bausch & Lomb sponsored study performed
by Dr. Hung Ming Lee (Tan Tock Seng Hospital, Singapore) demonstrates
superior precision for the IntraLase FS laser and equivalent short
term visual results, even though the newest IntraLase model was
not used. Moreover, the setting selected for the IntraLase flap
thickness was unusually high. In fact after this study Dr. Lee
now uses the IntraLase FS laser in the majority of his LASIK cases.
The study, which is being presented at a Bausch & Lomb sponsored
symposium, is not part of the peer-reviewed annual meeting of
the American Academy of Ophthalmology being held this week in
Chicago. Data released by B&L compared standard refractive
results and contrast sensitivity at one day, one week, and one
month post-operatively. Patients participating in the study had
flaps created in one eye by the Zyoptix XP and in the fellow eye
by the IntraLase FS laser operating at 15 kiloHertz (the older
model). Intraoperative measurements revealed the achieved flap
thickness averaged 118 microns in the Zyoptix eye, but was 30%
thicker (156 microns) in the IntraLase eye.
Unlike a mechanical microkeratome, the IntraLase FS is computer
controlled and can be set to achieve a wide range of flap thickness.
In several peer reviewed clinical studies (and in general clinical
practice) a much thinner flap thickness is programmed into the
laser and achieved, usually between 100 and 120 microns. Thicker
flaps have been reported to result in slower visual recoveries,
more significant biomechanical effects and optical aberrations.
Two separate prospective, contralateral eye studies done in the
United States at the US Navy Medical Center and at Stanford University
comparing the IntraLase FS laser and mechanical microkeratomes
are being presented at the AAO Refractive Subspecialty Meeting,
and the main AAO Annual Meeting, both peer reviewed meetings.
In these two studies, Dr. Edward Manche (Stanford University)
and Drs. Steven Schallhorn and David Tanzer (U.S. Naval Medical
Center) achieved flaps of 110 and 100 microns, respectively. In
both studies, statistically significant improvements in contrast
acuity and uncorrected vision were seen with the IntraLase FS.
More Good News for IntraLase
Despite the use of a flap thickness setting that was 50% greater
than a typical IntraLase setting, and over 30% thicker than the
thickness selected for the Zyoptix XP, the IntraLase flap achieved
a 30% reduction in standard deviation versus the mechanical device.
In the IntraLase eyes, a standard deviation of 9.5% was achieved,
while for the Zyoptix XP the standard deviation was 12.3% of the
average flap thickness. If equivalent flap thickness had been
used in the study, a standard deviation of 11 microns would have
been expected with the IntraLase, versus 15 microns with the Zyoptix
XP. This 11 micron extrapolation is consistent with several previous
peer-reviewed publications of the IntraLase FS. (Data on file)
IntraLase FS Laser Creates Planar Flap
Creation of a planar flap has been suggested as one of the primary
reasons for superior visual results with the IntraLase FS. While
a mechanical microkeratome produces an irregular flap that is
thinner centrally and thicker peripherally (meniscus shaped),
the IntraLase FS creates a uniform thickness flap. Therefore,
even a uniformly thicker IntraLase flap may better preserve the
integrity of the peripheral cornea and introduce fewer biomechanical
effects and optical aberrations than a centrally thinner mechanical
one. The equivalent visual results between IntraLase planar 156
micron flaps and Zyoptix XP 118 meniscus-shaped flaps are consistent
with this hypothesis.
Core Computer Technology Continues to Evolve
The study reports a two fold increase in suction time. With the
current model IntraLase FS30 the suction times would be roughly
equivalent (56 sec for FS30 vs. 44 sec for XP). Moreover the highest
volume LASIK surgeons in the world use IntraLase as their standard
of care dispelling any myths of prolonged surgery time. And the
core computer technology used in the IntraLase platform continues
to increase in speed.
The Bottom Line
"After using both the new Bausch & Lomb XP and the IntraLase
FS30, I am convinced the 30 kHz IntraLase provides both better
control of flap thickness and flap architecture and drives better
visual outcomes. Our patients definitely prefer the laser over
the blade. This is why we use IntraLase on essentially all of
our patients," states Jon Dishler MD of the Laser Institute
of the Rockies.
IntraLase congratulates Dr. Lee on his clinical study with Bausch
& Lomb. We are especially pleased to note that, after his
comparison study, he uses the IntraLase FS laser on the vast majority
of his LASIK cases.
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