Wavefront Treatment with the Carl Zeiss Meditec CRS-Master & MEL80 Excimer Laser

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


Night Vision – Starbursts & Haloes


Reduced Contrast Sensitivity

Natural vision contrast


Wavefront Technology

• Reduce high pre-operative aberrations

• Reduce surgical induction of aberrations

• Repair highly aberrated post-operative eyes

• Improve QUALITY of vision


Pre -3.25-0.50x102 Post +0.50-0.50x5

4.63 1.51

Reduce Aberrations

0.55 0.36


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?


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?


• 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


Aspheric Alone or Aspheric + Wavefront HO’s?

R

Spheric Aspheric Aspheric + Wavefront HO’s


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]


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


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


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


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



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


Safety


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



6 months3 months

Results: Contrast Sensitivity

* **

*

Average Post Operative Contrast Sensitivity


Average Contrast SensitivityPre-Operative 6 Month Post-Operative


*

**


Average Contrast Sensitivity

Aspheric Aspheric Wavefront Guided



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)


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


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%

Wavefront Treatment with the Carl Zeiss Meditec CRS-Master & MEL80 Excimer Laser

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