Utilizing the latest Refractive Technologies in Classik LASIK

Transcription

4 year experience in
custom ablations
ESCRS, Paris Sept. 2004
A. John Kanellopoulos, MD
Clinical Associate Professor NYU Medical School
Director, Laservision.gr Institute, Athens, Greece
www.brilliantvision.com
My Background
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Harvard Med School: Cornea Fellow
Cornell Un: Cornea Fellow
Harvard Med School: Glaucoma Fellowship
Medical Director: TLC Laser Eye Centers CT
Director of Refractive Surgery, NYU Medical School, NY
2000-2001
• Director, Laservision.gr Institute, Athens, Greece
• LASIK since 1993, over 11000 cases
Experience-Excimer Lasers
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Summit- Apex plus
VISX-S2 and S3
Lasersight
Nidek
Alcon-Ladarvision
B&L: Technolas 217
Wavelight: Allegretto-Wave
Wavelight: Eye-Q
One of the initial LASIK cases,
1993
Common problem with standard LASIK:
“goasting”
(large pupils, de-centered/small diameter ablations
etc)
Effects of Corneal Curvature on
Ablation Profile
Round spot shape,
even energy
distribution, 96%
energy absorption
Elliptical spot shape,
only 26% energy
absorption per pulse
Cornea
The ALLEGRETTO Wave compensates for the reduced
energy absorption in the periphery with more spots!
Result: True, large optical zone and ability to create prolate
cornea shape.
Effects of Corneal Curvature on
Ablation Profile
Round spot shape,
even energy
distribution, 96%
energy absorption
Elliptical spot shape,
only 26% energy
absorption per pulse
Cornea
The ALLEGRETTO Wave compensates for the reduced
energy absorption in the periphery with more spots!
Result: True, large optical zone and ability to create prolate
cornea shape.
Prolate Ablation
Prolate Cornea Shape
Prolate Cornea Shape with the ALLEGRETTO Wave
Oblate cornea shape with other refractive laser
systems
-7D myopia
corrected in same
pt
• One eye (top) with the
Allegretto-Wave
• The other eye
(bottom) with the
Technolas 217z
QuickTime™ and a DV/DVCPRO - NTSC decompressor are needed to see this picture.
Our Allegeretto-Wave and M2
experience in “standard LASIK”:
• 287 consecutive eyes, underwent LASIK for myopia or
myopic astigmatism.
• The Allegetto-Wave treats by a gaussian-profile flyingspot of 0.9mm, with 200Hz frequency and a 250Hz active
eye-tracker.
• We evaluated amount of myopia and astigmatism, pre- and
post-operative: UCVA and BCVA, IOP, endothelial cell
count and wavefront analysis by the Wavelight Tscherning
aberrometer.
Prolate or Wavefront-enhanced
LASIK
• Experience with the Allegretto
• Monitor with Wavefront analyzer
• Monitor with LCS (Vector vision)
Results:
(presented originally at the winter ESCRS meeting in Barcelona, Spain 2.2002)
• Mean values: The mean pre-operative sphere was
– 4.75 D (-1.00 to –12.50) and the cylinder –1.25
(-0.25 to –3.75)
• UCVA improved from 20/200 to 20/25. At 3
months 87% of the eyes were 20/20, 47% 20/15
and 32% 20/10. 100% of eye were within +/- 1D
at 3 months.
Results
100
90
80
70
60
50
40
30
20
10
0
8/10 (20/25)
10/10 (20/20)
12/10 (20/16)
15/10 (20/13)
Day 1
Month 1
Month 2
Month 3
Results:
“standard”-prolate LASIK
• Wavefront analysis showed a postoperative
increase in coma of only 35% (mean coma
of 6% pre-op to 9% post-op)
• 37% of eyes gained at least 1 line of BCVA
• No complications were noted in this limited
group
Pre- and Post-op Wave
BCVA improved 10/10 to 12/10
Case example:
Pre-op RE:
+2.00 –7.00 x 167 and
BCVA 6/10
3m post “standard”
LASIK :+0.50 -0.50 x 19
UCVA 9/10
In topographic terms all
of the cylinder corrected,
of importance the effective
ablation zone on
topography is exactly the
one planned with the
laser: 6.5mm
Same patient:
Orbscan measurements:
pre-op above and postop below
Results in 520 consecutive cases
myopic astigmatism
Results in 105 consecutive cases
Hyperopia and mixed astigmatism
My Technique
Placement of the M2
Microkeratome pass
Folding of flap, even moisture on
stromal bed
Check parameters
Intraoperative
moistute eq
Irrigation of flap
and careful wipe
2’ observation interval
Flap is evaluated with build-in slit-lamp
My technique
• 1 Drop of Alcaine
• Betadine drape
• Isolate eyelids with drape
• Aspirating speculum
• Lubricate blade and rotating parts
with Alcaine!!!
My technique
• Careful check of lock
• Alcaine during MK assembly
on eye
• Technician observes tubing
• Avoid pt sqeeze
My technique
• “Taco” flap to minimize
Dehydration
• Even bed hydration
very important
My technique
• Irrigation very important
• “Squeeze” out excees
fluid and
Striae with moist Weck-cell
• “milky” drop (predforte 1%)
to delineate gutter width,
centration and striae
UCVA: Spheres
Wavefront-guided for Ladar and Visx,
standard
for
Allegretto
LadarVision
Visx
Allegretto
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
91%
94%
81%
65%
35%
28%
Not Significant
20/12.5
72%
Not Significant
20/16
Ladar
Significantly
Worse than
Visx, Allegretto
20/20
Wavefront an important tool?
• Can monitor effects of LASIK
• Large (usually light-colored) pupils / High
astigmatism
• Enhancements (decentrations)-?TOPO
better
• “Enhancing” monovision
• Elucidate poor visual quality post refractive
surgery-treating unhappy eyes
Our Wavefront-guided
experience started with a pilot
study:
• 10 patients
• One eye wavefront-guided, the other
“standard” LASIK
• Wave group: RMSh pre-op 0.12-0.35
(0.17), post-op dropped to: 0.11. A
reduction therefore of HOA
• Non-wave: pre-op 0.165 post-op: 0.195 a
slight increase of HOA just as in our
larger standard LASIK group reported
Purpose of Study
• To evaluate the safety, efficacy and
accuracy of wavefront-guided LASIK
• To determine the spherical nomogram
adjustment
• To evaluate the wavefront pre- and postoperatively
Key specifications
that are important for
the clinician:
• - the frequency of the flying spot treatment is 200 Hz
• - the spot size is 0.9 mm;
• - its active eye-tracking system involves an infrared
camera and three individual illumination modules to sense
the eye movement (by fixing on
the pupilary reflex) with a detection frequency of 250 Hz
and a reaction time 6 to 8 msec
Method
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155 consecutive cases treated
Refractive errors:
-0.52 to -6.75 D
Average refraction:
-3.80 D
Astigmatism:
0.00 to -3.75 D
Average astigmatism: -0.85 D
Average age:
29.5 yrs
Method
• WaveFront evaluated prior to surgery (4 scans)
• Dilated pupil to 7mm (not cycloplegic, 1 drop
Mydriacyl 1%))
• Pre-op, Day 1, Week 1, month 1 and Month 3 Data
Wavefront-guided
QuickTime™ and a
DV - PAL decompressor
are needed to see this picture.
WaveFront
WaveFront basics
basics
HartmannShackSensor
TscherningSensor
+
well-known technique
+
variable incoming pattern
+
central cornea information
+
patient sees own aberrations
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expensive sensor
-
expensive low light sensor
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incoming light must be diffraction limited -
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insensitive of opacities
WaveLight Laser Technologie AG
sensitive against scattering
- no central cornea information
Laser, O=532nm
Laser Laser
Lens
AL
M
Mask
INPUT
IR-Led
IR-LED
CO
Telescope
S
Shutter
IR-Camera
OL1
Lens
Aperture stop
C2
C1
Fixation target
OUTPUT
VIS-High-Sensitive-Camera
WaveLight Laser Technologie AG 11/2001
OL2
Lens
ALLEGRETTO WAVE
WaveFront
WaveFront basics
basics
THE ALLEGRETTO WAVE ANALYZER
TS-Sensor
Opacity
Unsafe and misleading
It appears that even opaque eyes can
be measured because a clear image is
seen on the instrument display
But it is really caused by reflections of the lens.
ALLEGRETTO
WAVE
HS Sensor
Safe, only valid images can be processed
The individual beams are distracted by the
Opacity. No clear image can be seen, low risk of
accidentially treating with wrong data
By Thomas Zieger WaveLight Laser Technologie AG
INPUT
OUTPUT
WaveAnalyzer
Measurement
Measurement Principle
Principle
Data
Data Flow
Flow
INPUT
Optical Ocular
Aberrations
Measurement of
local distortions
Local
distortions
Calculation of
Wavefront Error
Calculation of
Ablation Profile
Custom
LASIK
WaveAnalyzer
OUTPUT
Correlation between theory and
night vision
Wavefront – guided Treatments
Michael Mrochen, PhD
University Hospital Zurich, Switzerland
Swiss Federal Institute of Technology, Switzerland
Ways
Ways of
of customized
customized treatments
treatments
Subjective
patient data
Patient
requirements
Objective
patient data
Investigator / Optometrist / Ophthalmic technician
Surgeon
Treatment
Treatment
planning
Empirical data
“Nomograms”
Computer
Assisted
Treatment
Environmental
factors
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
Predictability
of the Result and
Visual Outcome
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Accommodation
• Tear Film
• Optical Errors
• Pupil Size
• Lens
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Must be identical
• Fixation Target
• Center of Pupil
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Optical Setup and
Calibration
• z-Position of the Eye
• Eye Model
• Wavelength
• Image Processing
• Zernike Calculation
Wavefront
Measurement
Centration
Patient Eye
Performance
Eye Tracker
Performance
Laser
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
Wavefront
Measurement
Centration
• Resolution
• Numerical Calculations
• K-Readings
• Asphericity (prolate Cornea)
• Biomechanic
Patient Eye
Performance
Eye Tracker
Performance
Laser
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Beam Profile
• Laser Parameter
• Overlapping
• Numerical errors
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Resolution
• Scanner Speed
• Lateral Accuracy
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Tracking Speed
• Resolution
• Pupil Size
• Numerical Errors
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Laser Beam Profile
• Calibration of Energy
• Time-dependent
Deviations
• Suction
Wavefront
Measurement
Centration
Patient Eye
Performance
Eye Tracker
Performance
Laser
LASIK Procedure
Customized
Customized corneal
corneal ablation
ablation
Calculation
Spot Positions
Centration
Performance
Scanner
Calculation
Ablation Profile
• Outcomes
• Hinge?
• Flap?
• Wound Healing?
Wavefront
Measurement
Performance
Eye Tracker
Performance
Laser
Centration
Patient Eye
LASIK Procedure
Ablation depth =
3 x (max. wavefront – min. wavefront)
Scanning-spot
Scanning-spot lasers
lasers
Treatment
zone
Optical zone
Ablation profile
Laser pulses
Example:
Example: -1.5
-1.5 D
D myopia
myopia
10
Meridian at 0° and 90°
8
6
4
2
0
2
4
6
8
10
5
4
3
2
1
0
1
2
3
4
5
Example:
Example: 3rd
3rd order
order coma
coma
1.5mm
Pulse diameter
1.0mm
C7 = 0.5µm
0.5mm
0.5µm
Ablation depth
0.25µm
0.125µm
Example:
Example: 6th
6th -- order
order astigmatism
astigmatism
1.5mm
Pulse diameter
1.0mm
C23 = 0.25µm
0.5mm
0.5µm
Ablation depth
0.25µm
0.125µm
Treatment
Treatment time
time !!
Reducing the spot diameter by a factor of
2 results in an increase of the treatment
time by a factor of 4.
treatment time ~ ( spot diameter )
2
-4
-3
-2
-1
0
f = Winkelfrequenz
+1
+2
+3
Z rn,4 f
+4
r
k=0
k=3
k=6
k=4
k=7
k=5
k=8
k=9
k=10
k=11
k=12
k=13
k=14
Z nf
0
r1
k=2
k=1
r
2
r
3
r
4
n = radiale Ordnung
Zernike – Koeffizienten
Ten top pearls of my technique
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Wavefront monitoring essential for refractive surgery
Pt expectations
Understand the technology (surgeon-staff)
Aberration indices that REALLY matter
Preoperative measurements RE
Preoperative planning mesopic-scotopic pupil
Preoperative wave evaluation #, quality
Wavefront-guided OZ
Preoperative LASIK planning
Consistent flap, tracker, excimer energy
Importance of capture
Methods
Tserning aberrometer,
M2 and M2single use 130 and 110 heads
Results:
• Able to include 142 cases
• Mean values: The mean pre-operative sphere was – 4.85 D
(-1.00 to –6.50) and the cylinder –1.25 (-0.25 to –2.75)
• UCVA improved from 20/200 to 20/18. At 3 months 92%
of the eyes were 20/20, 57% 20/15 and 34% 20/10. 100%
of eye were within +/- 0.5D at 3 months.
Results: Efficacy
15
13
11
10.5
11.5
10.5
11.6
10.5
11.6
9
Pre-op BCVA
Post-op UCVA
7
5
3
1
-1
Day 1
Week 4
Month 3
Results: Safety
70
60
50
Loss of > 1 line
Loss of 1 line
No change
Gained 1 or more lines
Gained 2 or more lines
40
30
20
10
0
Day 1
Week 4
Month 3
Results Day 1:
Programmed vs. Achieved
1
0
-8
-6
-4
-2
-1
-2
-3
-4
-5
-6
-7
-8
0
Programmed
Achieved
0.5 DS Over
0.5 DS Under
Linear (Achieved)
Management of decentered
ablation with the use of
wavefront-guided LASIK
A.
John Kanellopoulos, MD
Laservision.gr Eye Institute, Athens, Greece
Manhattan Eye, Ear and Throat Hospital, NY
Michael Mrochen, PhD- Un. Of Zurich
Ablation decentration
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Troublesome compl. c serious visually debilitating side-effects.1, 9, 10
Causes:
Intra-op fixation error and/or drift of the patients’ fixation;
Ecc.-displaced treatment (surgeon error or equipment calibration error;
and eye tracker or eye tracker calibration error2).
Larger decentrations are usually associated with larger reductions
in low contrast sensitivity and visual acuity. 3
Mrochen M, Krueger RR, Bueeler M, Seiler T. Aberration-sensing and wavefrontguided laser in situ keratomileusis management of decentered ablation. J Refract Surg
2002; Jul-Aug, 18(4)418-29.
Verdon-W; Bullimore-M; Maloney-RK
Visual performance after photorefractive keratectomy: A prospective
study Arch-of-Ophthalmol 1996;(114/12):1465-1472
Treatment Centration
• Centration = important bias in measmnts as
well as reference points in laser treatments.
• The actual clinical measmnts of wavefront, are
centered by the coaxially cited corneal reflex,
the geometrical center of the cornea, the
corneal apex, and the entrance pupil, which is
the actual point where the visual axis goes
through.
• There are several the potential biases of
decentration of the human eye
Centration errors
sytematic and random
Systematic: a constant decentration
systematic caused by different axes (coordinate systems
defined in measurement and treatment, or the defined axis
where the coordinate system is not stable, the eye tracker is
calibrated imprecisely, there is head tilt, or the initial
alignment by the operator is not precise, or there is a
fixation problem from the patient).
Centration errors
Systematic centration errors can be avoided
with precise alignment techniques. Random
or dynamic centration errors are avoided
only with active eye tracking.
Random or dynamic centration errors, which
cause “smearing” of the ablation.
Active tracking
• A small pilot study compared the advantage of active eye
tracking. Twenty eyes treated with eye tracking and 20
eyes treated without eye tracking were evaluated with
regard to their wavefront indices.
• There was difference in wavefront measurements in
trefoil, quadrafoil, higher order astigmatism, and spherical
aberrations.
• Less stat. significant aberrations with the tracker-treated
patients. This study confirms others that show eye tracking
appears to improve the visual outcome of refractive
surgery.
Advantage of active eye tracking
in refractive surgery
U
UniversitätsSpital
Zürich
• 20 eyes treated with eye-tracker
• 20 eyes treated without eye-tracker
Tracker group
Non-tracker group
Absolute value [µm]
0.12
0.10
0.08
Preoperative higher-order
wavefront deviations in
both examined groups
0.06
0.04
0.02
0.00
3-fol
d
com
a
4-fol
d
s
high
. ord pher. ab
. ast
err.
.
On the importance of centration
Mrochen-M; Eldeine-MS; Kaemmerer-M; Seiler-T; Hutz-W
Improvement in photorefractive corneal laser surgery results using an active
eye-tracking system .J Cataract-and-Refractive-Surgery. 2001; 27/7 (1000www.brilliantvision.com
1006)
Methods
• We define the decentration zone by obtaining the
difference between the pre- and postoperative
corneal topographic measurements, which is a
tangential map.
• The ablation is surrounded by a region of
approximately zero power, determined with this
method described by Mrochen.2
• The decentration of the ablation is determined as a
distance of the center of the flattened zone from
the center of the pupil.
Methods
• We term an ablation grossly decentered if
this decentration is more than 1 mm
• There is evidence that decentration, even as
much as 100 microns, will significantly
increased higher aberrations and the
possibility of the symptoms described
previously to affect the patients’ visual
quality3
Treatment
• We treat decentered ablations with a preop
evaluation using wavefront measurements and
topographic measurements of the decentered
ablation.
• The preoperative measurements include visual
acuity, topography, OrbScan measurement as
mentioned previously, and wavefront
measurement.
• low contrast sensitivity measured by the Vector
Vision 3000 device
Treatment
• The wavefront-guided treatment is relatively standard.
• Only one drop of Alcaine (proparacaine 0.5%, Allergan,
Irvine, CA) as a topical anesthetic.
• We instill a drop of ofloxacin (Ocuflox, Allergan, Irvine,
CA) mixed with preservative-free Acular as antibiotic
prophylaxis several times during flap repositioning, and a
drop of PredForte.. (Fig. 6)
• We use PredForte to delineate the flap gutter and ascertain good
centration of the repositioned flap.
• Any differences in the gutter width, either on the X or Y axis,
even if the corneal markings are perfectly aligned, indicates a
decentration of the flap, which requires repositioning.
Results
• The 3 patients were followed the first day, first week, first
month, and then at three month intervals.
• The initial group of patients have subjectively improved
symptoms including night driving and quality of night
vision.
• All symptoms of monocular diplopia, ghosting and most of
the glare subsided after this treatment.
The pre-op and post-p corneal
topography,
The pre-op and post-p wavefront map
Conclusion
• In this small group we achieved significant improvement,
both in the signs and symptoms of decentered LASIK.
• Obvious limitations the relative corneal thickness and our
ability to perform an enhancement.
• Extreme decentrations, refractive errors, and higher order
aberrations may exceed the limits that this technology can
measure precisely.
• Other methods to treat aberrated eyes are currently under
study in the U.S.11
Conclusion
• There is also promising work being done in determining
the specific Zernike polynomials in higher order
aberrations are important functionally in humans.
• Better knowledge of the clinical correlation of these
findings may help us create more effective customized
enhancements.12,13 Further studies and clinical experience
will enhance our understanding of most effective and safe
methods to retreat aberrated eyes.
•
•
Applegate, RA, Sarver EJ, Khemsara V. Are all aberrations Equal? J Refract
Surg 2002. 18:S556-562.
Applegate, RA, Ballentine C, Gross H, et al. Visual acuity as a function of
Zernike Mode and Level of RMS Error, Optom and Vis Sci, in press.
Wavefront-guided anhancements
• Now 100% of our attempted enhancements
• Since flap is created already, little new
aberrations expected
• Ability to treat decentrations and night
vision problems
• Unhappy eye study with Wavelight
Unhappy eye study with Wavelight
Methods:26 consecutive eyes that had LASIK and were
symptomatic, underwent wavefront-guided treatment, based
on 4 reproducible aberration measurements. We evaluated pre, and post-operative refraction, total and high order aberrations
(RMSH), cornea and flap thickness, low contrast sensitivity
(LCS) and possible complications. Follow-up was 3-7 months
(4.5)
Results: 22 eyes were included. The mean values were:
refractive error: sphere: –0,92D (plano to –1.50) and cylinder:
-0.85D (0 to –1,75). UCVA improved from 20/25 to 20/18.
There was no loss of BCVA in any case. The RMSH
decreased from 0.62 to 0.25. LCS improved by 55%.
Sample study cases
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45 y/o male s/p LASIK for -5
OD : plano, BCVA 20/25+, LCS C4
OS: -0.50, BCVA 20/25+ LCS C5
WG enhancement OU, 6.5mm OZ
Post-op:
OD UCVA 20/20, LCS C6
OS UCVA 20/20, LCS C5
Pre and
post-op
data
Sample case
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28y/oF
LASIK for -7
OD UCVA 20/25, -0,75-1,00 15 C4
OS UCVA 20/15 plano
C6
WG enhancement OD, 6,5mmOZ
Post-op UCVA 20/15, C6
Case 5
• Old LASIK when 20y/o
• Did well for 2 years then developed KCN picture
• Management with INTACS-very happy but large
fluctuations of sphere (-2 to –8)
• Removed intacs placed ALTK sliver 120 microns
• Enhancement at 2 ms for -2.50-3.50 X 165
• 3 months post-op: 20/20
QuickTime™ and a DV - PAL decompressor are needed to see this picture.
Post-LASIK ectasia
• Minimal stroma: 280
• Minimal total K: 420
• Beware that microkeratome may become
unstable (usually they cut thinner though)
• Best treatment careful screening
Conclusion
• WaveFront-guided LASIK with the
ALLEGRETTO-WAVE (a 0.9mm flying-spot
and 200Hz) and the M2 appears to be safe and
very effective for correction of myopic
astigmatism
• It has demonstarted in our clinical practice the
ability to significantly reduce higher order
aberrations
Future Laser Parameters
that may be required !
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Spot diameter: 0.2 mm
Repetition rate 2000 Hz
High speed eye tracking
High accuricy centration – registration
Non contact microkeratomes
Method
• WaveFront evaluated prior to surgery (4 scans)
• Dilated pupil to 7mm (not cycloplegic, 1 drop
Mydriacyl 1%))
• Pre-op, Day 1, Week 1, month 1 and Month 3 Data
Wavefront-guided retreat
in symptomatic LASIK
eyes
AAO 2004
A.
Methods:
• 26 consecutive symptomatic eyes p LASIK
• Pre-, and post-operative refraction,
• Total and high order aberrations (RMSH),
cornea and flap thickness,
• Contrast sensitivity (CS) and possible
complications. Follow-up was 6-12 months
(7.5)
• Pupil size
Inclusion Criteria
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RE within +/-1.50.
W-G treatment had to be > 6mm OZ
RMSH > 0,4 at 6mm pupil
At least one of the below indications:
small OZ, decentered ablation, irregular
astigmatism, night vision problems,
under- or over- correction
Surgical technique
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•
•
All cases re-lift
Intra-operative subtraction pachymetry
Treated 6, 6.5 and 7mm Ozs
Utilized the average of 4 reproducible WFs
Results:
22 eyes treated
The mean values were:
RE: sphere: –0,92D (plano to –1.50)
cylinder: -0.85D (0 to –1,75).
UCVA improved from 20/25 to 20/18.
There was no loss of BCVA in any case.
The RMSH decreased from 0.62 to 0.25.
Contrast Sensitivity improved by 55%.
Original +0.50 -2.50
OD:+1.50 -1.75 30
IRREGULAR BCVA 20/60 to
20/25
Original +1.00 -3.00
OS: +1.75-175 130
IRREGULAR BCVA 20/50 to
20/25
Old LASIK for 3D cyl, now
+1.50-150cyl had wave-guided:
plano
Same pt other eye
RMSH improved from
1,2 to 0.36 (!) LCS
improved from C3 to
C7 (!)
Same patient
Conclusion
• WaveFront-guided LASIK with the
ALLEGRETTO-WAVE (a 0.9mm flyingspot and 200Hz) appears to be safe and
very effective for correction of high order
aberrations
• It has demonstarted in our clinical
practice the ability to significantly
improve contrast sensitivity
Conclusions
• Wavefront and topography-guided
applications show unsurpassed
accuracy and reliability
• Effective and STRICT protocol
remains essential for great results.
Utilizing topography-guided
LASIK and PRK
June 2004
A.
Why topo-guided
•
•
•
•
•
•
Wavefront-guided has several limitations:
1-Tissue reserve
2- ability to capture reliable image
3-Clinical judgment on planned ablation
TOPOGRAPHY is possible on most eyes
90% of HOA are on the cornea (!) therefore
addressed with topography-driven ablation
T-CAT software
• Available on the Oculus topography
transformed platform: Allegretto topolyzer
• Clinical use since early 2003
• Now Over 60 cases experience
Technique
•
•
•
•
•
8 reproducible maps of over 70% quality
Feed data in T-CAT software
Adjust Q value (-0.30 to -0.46)
Enter thickness and keratometry data
Evaluate ablation pattern with and without
TILT
Initially -10, 505µ
LASIK: 4,5mmOZ, 125µ flap M2
->plano ^BCVA 2 lines, but
night halos
Topo-guided Tx to enlarge OZ to
6mm and adjusting Q value to -1,46
Initially halos gone, RE -1.25
Old K perf, s/p CE, IOL,
now -1,50 -250 160 irregular
BCVA 20/40+
Topo-guided, Q adjustment to -0.3
Postop: UCVA 20/30, BCVA 20/25
Complicated CE-AphakiaArtisan IOLP -350 90 BCVA 20/60
Postop +0.50-0.50 90 UCVA
20/25
Initially: +3.50 -3.00
180, pLASIK:+1.001.25 70 UCVA 20/40
BCVA 20/25
pTOPOG: plano -0.25
UCVA 20/20
10 year postRK, +2,50 1,50Cyl,
debilitating
night vision.
Post-LASIK: 0.50 -0.50
marked
improvement
S/p LASIK for =4.50, now +1.00 and
night vision down C3
PK reduction of cylinder by 7D
Iatrogenic KCN, s/p
ALTK then LASIK
enhanceemnt topoguided
S/p PRK for -3.50, 7 mm pupil, is 20/20 but
“Ghoasting” day and night. Topo-guided PRK to 7,5
mm 4 week result
Same patient pre- and postOrbscan topos at 1 month
Another RK case, +2 -1.75 added
-1.25 RX. Post: -0.25 -0.5cyl
Who does it work?
Conclusions
• Allegretto’s topography-guided results offer
unprecedented accuracy and reliability
• Q-value adjustment may be essential in
improving visual quality.
• Refractive predictability needs steep learning
curve
• Topograhy capture is an art as much as
science (dry eye, blepharitis, deep orbits etc)
Conclusions
• Topography remains a surgeon’s tool and a
means of effective symptomatic relief without
significant tissue requirements
• Today’s refractive surgeon must have access to
effective customization techniques
• All lasers should correct their profiles to
minimize induced spherical aberrations -the
solution may be in Q value-adjusted treatments
Q value in humans: -0.46
Spherical Aberration 2
Oblate Cornea,
Q = 0.45
Spherical
Aberration cont’d
Spherical Aberration is a
function of Asphericity (Qvalue).
In general, prolate
corneas show less sph.
aberr. than oblate
corneas. At one Q-value
(Q = -0.46), sph. aberr. is
at a minimum to a certain
extend.
F2
F3
Prolate Cornea,
Q = -0.46
(Be aware of limits !)
F1
F1
-7D myopia
corrected in same
pt
• One eye (top) with the
Allegretto-Wave
• The other eye (bottom)
with the Technolas 217c
• Larger ablation with the
Allegretto is a result of
better approach to prolate
cornea
Why
Why is
is Q
Q value
value important?
important?
1.6
1.2
0.8
0.4
0
-10
-8
-6
-4
-2
refractive correction sph. equ / D
Courtesy Prof. Seiler
0
change in Q-value (Q20)
2.0
The
The preliminary
preliminary Data
Data on
on Q
Q adjusted
adjusted LASIK
LASIK
+2.0
+1.2
+0.8
+0.4
0
-10
-8
-6
-4
-2
refractive correction sph. equ / D
0
-0.4
postop Q-value (Q20)
+1.6
Possible
Possible Applications
Applications (Pre-op)
(Pre-op)
OD
OS
-5.0 cyl -0.5/175° = 6/6 +1
-5.0 cyl -0.5/5° = 6/6 +2
Possible
Applications (Post-op)
(Post-op)
OD Q-factor optimized
OS wavefront-guided
UVA 20/16+1
UVA 20/16
nc
i
y
l
t
n
e
r
cu
l
a
c
i
lin
ls
a
i
tr
Q20 = -0.1
Q20 = +0.4
Possible
Applications (Presbyopia)
(Presbyopia)
Male, 52 years
Preop data:
+2.5 cyl -0.5/10°
dist VA 1.25
near VA 0.1 (dist.
Corr.)
Q20 = -0.16
Possible
(Presbyopia)
Male, 52 years
Op data:
+3.0 cyl -0.5/10°
attempted Q
Q20 = -0.6
Possible
(Presbyopia)
3 days postop
-0.25 cyl -0.5/2°
dist UVA 1.0
near UVA 0.6
Q20 = -0.54
c
in
y
l
t
n
e
r
r
u
ls
a
i
tr
l
a
c
i
n
cli
Our current protocol
• Myopes: 70% standard prolate-optimized
treatment
• F-CAT with the Eye-Q, 400Hz, Q-value
adjustment
RMSH>0.4 Wavefront-guided
High cylinder: topo-guided
• Hyperopes: 100% topo-guided with q-value
adjustment
• Enhancements: 100% custom
My view of the future practice
• All routine cases treated with the Eye-Q,
400 Hz, Q-value adjusted (large optical
zones, good night time vision, possible
better for presbyopia!
• Highly aberrated yes treated with
Wavefront or topo-guided
• Most enhancements customised
Thank You

Utilizing the latest Refractive Technologies in Classik LASIK

Transcription

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