Wavefront lasik and PRK still increases your high order aberrations and distortions!

Very good read and information people did not previously know! Still
want lasik/prk after you are done reading the facts below?


Despite what many claim they experience, you cannot have better vision
post PRK than you would have pre-PRK with correction. All types of
refractive surgery induce higher order aberrations. Even customized
wavefront ablations. The aberrations that wavefront guided ablations
induce are just not as severe.

correction systems which couples their Zywave aberrometer and their
orbscan topographer with their Technolas 217z laser:

Although the ZyWave® Wavefront System measures the refractive error
and wavefront aberrations of the human eyes, including myopia,
hyperopia, astigmatism, coma, spherical aberration, trefoil, and other
higher order aberrations through fifth order, in the clinical study for
this PMA, the average higher order aberration did not decrease after
Zyoptix Personalized Vision Correction.
The aberrations induced by wavefront PRK are simply not as bad as those
induced by traditional PRK. What does this mean?: All refractive
surgeries induce aberrations, which can lead to decreased contrast
sensitivity (among other things such as haloes, double vision,
starbursts), and it is impossible, at least with todays technology, to
have better vision with PRK than what you would be able to get with
contacts. This is especially true with RGPs, which can decrease higher
order aberrations by around 70% (much better than you would get with
PRK, which at best is no net gain in aberrations).




Wavefront-guided PRK causes less increase in overall aberrations than
conventional PRK in myopic patients

Roibeard O'hÉineacháin
in Rome

CUSTOMISED PRK using the Zyoptix (Bausch and Lomb) system appears to
increase higher order aberrations to a lesser degree than conventional
PRK in patients with myopic astigmatism, according to the results of an
Italian study presented at the 7th ESCRS Winter Refractive Surgery
Meeting.



In spite of the improvement caused by the addition of these features,
custom wavefront guidance leads to ablations that often increase
higher-order aberrations, Dr. Holladay says.


http://www.grendahl.com/wavefront/wavefront_system.html

High order aberrations no one wants!


When comparing wavefront to standard LASIK there was an attempt during
an Ophthalmic devices panel meeting to include the word 'reducing' when
referring to higher order aberrations. Aberrations induced by wavefront
are reduced when compared to standard LASIK, but they are CERTAINLY not
reduced when compared to the virgin eye. Wavefront treatments, in fact,
were found to induce aberrations in virgin eyes in clinical trials. A
conscientious doctor on the panel put the skids under the use of the
term 'reducing' when describing wavefront aberrations. Thank you, Dr.
Bullimore.
-----------------------------------------------
Excerpt:
http://www.fda.gov/ohrms/dockets/ac...ipts/3883t1.doc
DR. WEISS: Can you repeat the first one again?

DR. GRIMMETT: Sure. Wavefront-guided LASIK does not reduce the level of
higher-order aberrations of the preoperative eye.

DR. WEISS: Would that not be confusing to someone? Wouldn't that be
confusing?

DR. GRIMMETT: Michael Grimmett.
It may suggest somehow wording in that wasn't it that the higher-order
aberrations were 20 percent higher than the preop eye in the
wavefront-guided versus what, 80 percent was the number?

PARTICIPANT: Seventy-seven percent.

DR. WEISS: In here, is there any place saying that LASIK itself
increases aberrations and that customized corneal ablation increases
them less than conventional treatment?

DR. GRIMMETT: I think that's the idea.

DR. WEISS: So maybe we could put that wavefront-guided ablation ??

DR. GRIMMETT: Conventional LADARVision LASIK increases higher-order
aberrations by that figure 77 percent while wavefront-guided LASIK
increases them by whatever, 20 percent, whatever the number is, or you
can say reduces them to a 20-percent level, if you want to use the word
"reduces."

DR. BULLIMORE: I would avoid the term "reducing."
-------------------------------------------------
So when you say spherical aberration is 'reduced', it's reduced
compared to WHAT, in what population? Is spherical aberration 'reduced'
for large pupil patients as well (likely NOT). Are total higher order
aberrations decreased?

Please keep in mind that in VISX clinical trials, from the data we have
available... 1 in 5 patients did not hit 20/20 at the 12 month mark.

So wavefront can't even do reliably what glasses can do. Let alone the
induced corneal distortions and fried nerves.

I completely agree with Dr. G on this. The overwhelming liklihood is
that refractive surgeons are still out there giving patients corneal
distortions without their informed consent.

I think patients who do their research will find that the strongest,
healthiest and least aberrated corneas they will ever have are their
virgin corneas.