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VISX STAR S4 IR |
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WAVELIGHT
ALLEGRETTO |
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BAUSCH & LOMB |
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LADAR VISION 4000/6000 |
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NIDEK EC 5000 |
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Customized Wavefront Treatments |
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Yes - Widest FDA approval of any laser system worldwide |
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Limited |
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Limited |
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Limited |
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No |
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Wavefront
Resolution |
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Fourier algorithm
offers highest
resolution of
wavefront error |
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Zernicke
algorithm
interpolates and
smoothes data
artificially |
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Zernicke
algorithm
interpolates and
smoothes data
artificially |
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Zernicke
algorithm
interpolates and
smoothes data
artificially |
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Zernicke
algorithm
interpolates and
smoothes data
artificially |
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Active 3-D Eye Tracking |
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Yes |
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No - 2-D only |
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No - 2-D only |
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No - 2-D only |
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No - 2-D only |
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Iris Registration |
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Yes - Centers
& aligns
treatment
independent of
pupil center migration
& eye cyclorotation |
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No - Manual
marking only -
less accurate
and subjective
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No - Manual
marking only -
less accurate
and subjective |
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No - Manual
marking only -
less accurate
and subjective |
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No - Manual
marking only -
less accurate
and subjective |
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Compensates for
pupil migration
during physiologic
pupil dilation |
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Yes - centers
and aligns
treatment independent
of pupil
migration |
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No |
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No |
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No -
Pharmacologic
pupil
dilation required
for tracking
creates potential
for centering error |
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No |
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Requires
peri-operative
use of eye drops
that impair
healing |
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No |
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No |
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Yes |
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Yes |
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No |
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Size of Laser Beam |
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Small and large
spot for rapid
treatment and
optimized to
reduce thermal
injury to tissue |
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Small spot only
but very high
speed reduces
tissue dehydration
during laser
photoablation |
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Small spot only
- slows treatment
and allows for
tissue dehydration
during laser
photoablation |
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Small spot only
- slows treatment
and allows for
tissue dehydration
during laser
photoablation |
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Scanning slit |
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Thermal Damage to Cornea |
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Variable spot
scanning and
variable rep rate
reduces thermal
effects |
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Higher speed
and excellent beam
characteristics may
reduce thermal
load to tissue |
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High speed
and small spot
can be prone to
thermal and
drying effects
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High speed
and small
Gaussian spot
prone to thermal
and drying effects |
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Scanning slit
creates heat
that damages
tissue |
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Physician choice |
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Largest market
share in the US
and growing rapidly
(VISX invented
laser vision
correction) |
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Limited physician
acceptance to
date |
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Limited physician
acceptance to
date |
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Shrinking physician
acceptance &
numerous post
market complaints
at FDA (see FDA
MAUDE database)
6000 is currently
recalled by the FDA |
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Shrinking
physician
acceptance due
to aging
platform |
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Safety in
conservation
of corneal
tissue |
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Conservative
leaving good
residual for
strength |
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Conservative
leaving good
residual for
strength |
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Aggressive
system that
is often tissue
"hungry" |
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Aggressive
system that
is often tissue
"hungry" |
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Conservative
leaving good
residual for
strength |
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Enhancement
Rate |
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Low - Typically
less than 5% |
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Low - Typically
less than 5% |
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Insufficient Data
Available for
Comparison |
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Many centers
report high rates
of retreatments
from overcorrection |
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Higher reported
rates due to
aging platform |
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