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Home > Archive > Lasik Eyes Surgery > December 2005 > Wavefront without focus
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Wavefront without focus
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| Michael 2005-12-18, 11:01 am |
| I recently had my eyes examined by a refractive surgeon clinic and a
Visx wavefront scan was made on my eyes. One of my eyes is treated with
PRK several years ago and the Visx couldn't focus on that one
sufficiently, as the operator said, because of the PRK made so no
results could be produced. The Visx had no problems with the other, not
treated, eye. Is this a common problem with Visx wavefront analysis?
Michael
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| Glenn - USAEyes.org 2005-12-18, 6:06 pm |
| What you describe affects virtually all aberrometers that are used by
excimer lasers because they all use the Hartmann Shack technology.
Hartman Shack requires a grid of light to move into the eye, bounce
off of the retina and back out of the eye into a series of small
lenses. If the eye has too many aberrations, the light is unable to
travel all this distance.
The Tschering wavefront technology uses a different methodology to
derive the same data and is able to penetrate just about any
aberration. Unfortunately, this technology was not adopted by the
laser manufacturers.
If you can find a doctor who has a Tracey ray-tracing visual function
analyzer, the readings could be taken and then extrapolated for use
with the Visx S4 laser.
It would appear that your eye that has already had PRK has significant
aberrations, hazing in the cornea, or the development of a cataract in
the lens.
Glenn Hagele
Executive Director
USAEyes.org
"Consider and Choose With Confidence"
Email to glenn dot hagele at usaeyes dot org
http://www.USAEyes.org
http://www.ComplicatedEyes.org
I am not a doctor.
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| Michael 2005-12-18, 6:06 pm |
| Thanks. Your guess is correct; there are aberrations and a scar causing
haze but no cataract.
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| Glenn - USAEyes.org 2005-12-18, 6:06 pm |
| You may want to discuss techniques to resolve the scaring, such as
Mitomycin C or Phototherapeutic Keratectomy (PTK), but what can be
done depends greatly on the nature of the scaring. I recommend that
you be evaluated by a corneal specialist. If you would like referral
assistance, let me know.
Glenn Hagele
Executive Director
USAEyes.org
"Consider and Choose With Confidence"
Email to glenn dot hagele at usaeyes dot org
http://www.USAEyes.org
http://www.ComplicatedEyes.org
I am not a doctor.
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