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Home > Archive > Lasik Eyes Surgery > July 2006 > Ophthalmology. 2004 Dec;111(12):2175-85. Conclusion is wavefront increases, induces MO
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Ophthalmology. 2004 Dec;111(12):2175-85. Conclusion is wavefront increases, induces MO
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| Ophthalmology. 2004 Dec;111(12):2175-85.
Wavefront-guided LASIK with the Zyoptix 3.1 system for the correction
of myopia and compound myopic astigmatism with 1-year follow-up:
clinical outcome and change in higher order aberrations.
Kohnen T, Buhren J, Kuhne C, Mirshahi A.
Department of Ophthalmology, Johann Wolfgang Goethe-University,
Frankfurt am Main, Germany. kohnen@em.uni-frankfurt.de
OBJECTIVE: To assess safety, efficacy, predictability, stability, and
change in aberrations after wavefront-guided LASIK for myopia and
myopic astigmatism.
DESIGN: Prospective, nonrandomized, self-controlled trial.
PARTICIPANTS: Wavefront-guided LASIK was performed in 97 eyes in a
1-year trial. Treated eyes had a mean subjective manifest spherical
equivalent (SE) of -5.22+/-2.07 diopters (D), with a range of -0.25 to
-9.00 D of myopia and 0 to -3.25 D of astigmatism.
INTERVENTION: After a microkeratome cut, a wavefront-based excimer
ablation (Zyoptix 3.1) was performed. The full treatment to achieve
emmetropia of an early nomogram provided by the system manufacturer was
used in all procedures.
MAIN OUTCOME MEASURES: Safety, efficacy, predictability, and stability
were evaluated at 1, 3, and 12 months postoperatively. Wavefront
changes of higher order aberrations (HOAs) at 1 year were determined
for pupil sizes of 3.5 and 6 mm. RESULTS: At 1 year postoperatively,
uncorrected visual acuity (VA) was 20/20 or better in 83% of the eyes,
and 20/40 or better in 98%. The mean subjective manifest SE at 1 year
was -0.25+/-0.43 D; it was within 0.50 D in 77% and within 1.0 D in
95%. No eye lost > or =2 lines of best spectacle-corrected VA (BSCVA)
at 1 year postoperatively; 40 eyes gained 1 line of BSCVA, and 5 eyes
gained 2 lines. The total HOA root mean square (RMS) increased on
average by a factor of 1.23+/-0.57 with a 3.5-mm pupil; for the 6 mm
pupil, the increase factor was 1.52+/-0.36. No change or reduction in
the total HOA RMS was observed in 45.5% of the eyes for a 3.5-mm pupil
and in 20.6% for a 6-mm pupil. There was a significant increase of
primary spherical aberration (Z 4,0) by a factor of 4.11+/-10.17 for
3.5-mm pupils and 4.31+/-6.76 for 6-mm pupils.
CONCLUSIONS: Wavefront-guided LASIK using Zyoptix 3.1 is an effective
and safe procedure for the treatment of myopia and myopic astigmatism.
Although in close to half of the eyes HOAs could be reduced, there was
still undercorrection and induction of HOAs with the algorithm
employed.
BE's comment: Notice how they reported the post-op wavefront
measurements at a 3.5 mm pupil and 6.0 mm pupil. They wouldn't DARE
report the wavefront measurements larger than 6.0 mm because the
INCREASE in HOAs would be ALARMING!!! How do they get away with this?
These numbers are meaningless to patients with pupils larger than 6.0
mm. As I've said many times before, that's like weighing a 250 lbs.
woman on a scale that only goes up to 150 lbs. This is a perfect
example of the way the industry covers up the continuing problem of
visual impairment in dim light in patients with large pupils!
Ace's comment: Whoa thats alot of extra aberrations at 6mm pupils! It
would be terrible for those with 7mm, 8mm or larger pupils! It does
reduce your myopia and astigmastim but not always eliminates it. Those
who "gained" a line of vision is because glasses minifies everything,
making the 20/20 line too small to read. 83% may be 20/20 but this isnt
the case over the long term as lasik does not stop the eye from
changing. Also regression is common due to corneal bulging and
sometimes an increase in axial myopia. I am not bashing lasik here, it
works to get you closer or even reach plano, I only present the facts
that todays lasik, even wavefront still induces 50% more aberrations
with 6mm pupils and possibly doubles your aberrations with 8mm+ pupils.
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