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Home > Archive > Lasik Eyes Surgery > April 2005 > Concerns regarding P-IOL measurement
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Concerns regarding P-IOL measurement
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| Glenn - USAEyes.org 2005-04-12, 11:47 am |
| The issue has been raised before, but deserves mentioning again. The
method to determine the appropriate size of the STAAR ICL phakic
intraocular lens (P-IOL) is to measure the distance from the white to
white across the cornea. This is supposed to be equal to the width of
the area inside the eye where the P-IOL will be implanted. We have
voiced concern on this method of measurement, as have many others.
In an article in the current edition of Ocular Surgery News, a
European surgeon reports his findings, which appear to echo our
concerns.
"ROME - Measurement of the white-to-white distance can no longer be
accepted as a sufficient method for sizing posterior or anterior
chamber IOLs, according to Philippe Sourdille, MD. "White-to-white
does not correspond to the internal diameter, and it's the internal
diameter that we need to measure precisely," he said. "
Visit http://www.osnsupersite.com/default.asp?ID=10202 for the whole
article.
The FDA accepted the white-to-white measurement as protocol for the
clinical trials of the STAAR ICL P-IOL, so results are based upon this
technique. If/when it ever gets approved, the outcomes are based upon
the white-to-white technique, which may be less than optimal.
Glenn Hagele
Executive Director
Council for Refractive Surgery Quality Assurance
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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| Glenn,
As you had indicated before, if someone were interested in getting the
best measurment available for this procedure, they could seek out an
ultrasound immersion device (Artemis) to do this measurement. I am
cut-and-patsting that response in the event that someone might be
seeking this procedure, and wants to know a "better" measurement
technique.
r
Glenn said:
Thanks for the clarification and expansion. You are absolutely
correct.
Yes, using ultrasound immersion technology (Artemis) to measure for
IOLs (especially P-IOLs) is excellent, very accurate, and is the
direction I hope the industry goes, however that is not the current
norm. In fact, I believe there are less than two dozen of these
devices in the entire US.
The vast majority of patients are measured with white-to-white and this
is the technique submitted to the FDA for its approval consideration of
the STAAR ICL P-IOL. White-to-white is what the manufacturers of STAAR
say is the recommended protocol.
The issue is especially critical for the STAAR ICL because it needs to
sit in a ridge in the ciliary sulcus that may not even exist and cannot
be seen by conventional methods. The immersion ultrasound can
determine not only the appropriate size measurement, but can show if
this necessary component is intact on the patient and the STAAR ICL is
an appropriate choice.
If I had my way (and I seldom do), Artemis or similar evaluation would
be standard of care.
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