Wavefront Treatment with the Carl Zeiss
Meditec CRS-Master and MEL80 Excimer
Laser
Dan Z Reinstein MD MA(Cantab) FRCSC1,2,3,4
1. London Vision Clinic, London, UK2. St. Thomas’ Hospital - Kings College, London, UK 3. Weill Medical College of Cornell University, New York,4. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche) , Paris, France
©DZ Reinstein [email protected]
Why do we need Wavefront Sensing?
• Current metric of success– Snellen chart (100% contrast) – Quantity of vision
• New metrics of success - Quality of vision– Night Vision– Contrast Sensitivity
20/2020/2020/2020/20
©DZ Reinstein [email protected]
Night Vision – Starbursts & Haloes
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Night Vision – Starbursts & Haloes
©DZ Reinstein [email protected]
Wavefront Technology
• Reduce high pre-operative aberrations
• Reduce surgical induction of aberrations
• Repair highly aberrated post-operative eyes
• Improve QUALITY of vision
©DZ Reinstein [email protected]
Pre -3.25-0.50x102 Post +0.50-0.50x5
4.63 1.51
Reduce Aberrations
0.55 0.36
©DZ Reinstein [email protected]
What has wavefront sensing taught us?
• Munnerlyn based ablation induces +++++spherical aberration (Z4,0)
• Aspheric ablation induces +++ (less) spherical aberration (Z4,0)
• Can Wavefront improve on aspheric ablation?
Can the wavefront add benefit to
aspherically optimised sphero–cylindrical
treatments?
©DZ Reinstein [email protected]
What has wavefront sensing taught us?
• Spherically based ablation induces +++++spherical aberration (Z4,0)
• Aspheric ablation induces +++ (less) spherical aberration (Z4,0)– Reducing induced spherical aberration
improves contrast sensitivity
• Can Wavefront HO’s improve outcomes beyond just aspheric ablation?
©DZ Reinstein [email protected]
• Paired eye control:(aspheric profile) vs
(aspheric profile + wavefront)
Aspheric Alone or Aspheric + Wavefront HO’s?
• Prospective study
• Twenty-five LASIK patients
• WASCA/CRS-Master, MEL80
Aspheric Aspheric +HOA
©DZ Reinstein [email protected]
Aspheric Alone or Aspheric + Wavefront HO’s?
R
Spheric Aspheric Aspheric + Wavefront HO’s
©DZ Reinstein [email protected]
Preoperative parameters
• Eye pairs within 0.75 D spherical equivalent
AsphericAspheric Wavefront
Guided
Spherical Equivalent-4.10 ± 1.80
[-1.88, -7.50]
-3.97 ± 1.79
[-1.25. -7.38]
Cylinder-0.53 ± 0.44
[0.00, -1.50]
-0.60 ± 0.40
[0.00, -1.25]
Higher Order RMS0.30 ± 0.096
[0.13, 0.47]
0.31 ± 0.098
[0.14, 0.62]
©DZ Reinstein [email protected]
Laser Spherical Equivalent vs. Achieved Spherical Equivalent Primary LASIK Procedures MEL80 For Non-Wavefront Guided
y = 1.01x + 0.1549
R2 = 0.9708
-8
-7
-6
-5
-4
-3
-2
-1
0
-8-7-6-5-4-3-2-10
Attempted Spherical Equivalent Change
Ach
ieved
Sp
heri
cal Eq
uiv
ale
nt
Ch
an
ge
Aspheric
Results: Precision
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Laser Spherical Equivalent vs. Achieved Spherical Equivalent Primary LASIK Procedures MEL80 For Wavefront Guided Treatments
y = 0.9669x - 0.1283
R2 = 0.963
-8
-7
-6
-5
-4
-3
-2
-1
0
-8-7-6-5-4-3-2-10
Attempted Spherical Equivalent Change
Ach
ieved
Sp
heri
cal Eq
uiv
ale
nt
Ch
an
ge
AsphericWavefront Guided
Results: Precision
©DZ Reinstein [email protected]
MEL80 LASIK Myopia Efficacy: Uncorrected Acuity
28%
76%
96%100% 100%100%
68%
24%
0%
20%
40%
60%
80%
100%
Uncorrected Visual Acuity
Cu
mu
lati
ve P
erc
en
tag
e O
f Eyes
Wavefront [25] 28% 76% 96% 100%
Standard [25] 24% 68% 100% 100%
20/12.5 20/16 20/20 20/25
Add Wavefront to Aspheric Treatment?
Efficacy
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MEL80 LASIK Myopia Accuracy: Within range of intended
96%
80%
60%
100% 100%
92%
84%
68%
0%
20%
40%
60%
80%
100%
Accuracy (Diopters)
Cu
mu
lati
ve P
erc
en
tag
e O
f Eyes
Wavefront [25] 60% 80% 96% 100%
Standard [25] 68% 84% 92% 100%
Within 0.25D Within 0.50D Within 0.75D Within 1.00D
Accuracy
Add Wavefront to Aspheric Treatment?
©DZ Reinstein [email protected]
MEL80 LASIK Myopia Safety: Change in BSCVA
0% 0%
4%
52%
44%
0%
4%
8%
44%44%
0%
10%
20%
30%
40%
50%
60%
Lines Change in BSCVA
Perc
en
tag
e O
f Eyes
Wavefront [25] 0% 0% 52% 44% 4%
Standard [25] 0% 4% 44% 44% 8%
Loss 2 or More
Loss 1 No Change Gain 1Gain 2 or
More
Add Wavefront to Aspheric Treatment?
Safety
©DZ Reinstein [email protected]
Comparing The Change In Seidel Coefficients Between Wavefront Guided Treatments And Non-Wavefront Guided Treatments
-2.014
-2.577
-3.0
-2.0
-1.0
0.0
Avera
ge C
hange (
mic
rons)
Aspheric Wavefront -2.014
Aspheric -2.577
T-test p value 0.003
Spherical Aberration
Average Induction of Seidel Spherical Aberration
~ 20% less Induced Spherical Aberration
Significant
Add Wavefront to Aspheric Treatment?
©DZ Reinstein [email protected]
6 months3 months
Results: Contrast Sensitivity
* **
*
Average Post Operative Contrast Sensitivity
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Average Contrast SensitivityPre-Operative 6 Month Post-Operative
Results: Contrast Sensitivity
*
**
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Average Contrast Sensitivity
Aspheric Aspheric Wavefront Guided
Results: Contrast Sensitivity
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Average Pre Op Zernike Coefficients
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Zernike Coefficients
mic
rons
Average -0.07 -0.09 -0.02 0.00 0.01 -0.01 0.20 0.01 -0.01
Standard Deviation 0.15 0.18 0.10 0.13 0.05 0.05 0.12 0.06 0.05
Z(3,-3) Z(3,-1) Z(3,1) Z(3,3) Z(4,-4) Z(4,-2) Z(4,0) Z(4,2) Z(4,4)
Average Pre Op Zernike Coefficients
Discussion: Pre-op levels of HOAs
Mean HO RMS: 0.30 µm(OSA Notation)
©DZ Reinstein [email protected]
Conclusions
• Addition of HOAberrations to aspheric sphere and cylinder treatment results in:
– No loss of accuracy in refractive outcomes– Reduced induction of spherical aberration– Possible benefits to postoperative contrast
sensitivity
©DZ Reinstein [email protected]
Benefit of Aspheric-WF over Aspheric
0
0.5
1
1.5
2
2.5
3
Patient 1 (-7 ASA) Patient 2 (-7 ASA)
InductionPreop Z4,0
-50%
-50%
Sp
heri
cal A
berr
ati
on
Z4
,0
-50%
-50%
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