the great femtosecond face-off: carl zeiss meditec visumax

The Great Femtosecond Face-off:

Carl Zeiss Meditec VisuMax

Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4

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]

Financial Disclosure

The author (DZ Reinstein) acknowledges a

financial interest in Artemis™ VHF digital

ultrasound (ArcScan Inc, Morrison, CO)

The author (DZ Reinstein) is a consultant for

Carl Zeiss Meditec AG (Jena, Germany)


• The Bermuda triangle of treatment parameters– Short procedure time– Easy flap lift / tissue separation– Excellent cut quality– No adverse effects (DLK, TLS)– Accurate focusing

• Flaps• FLEX

Pulse Rate

Precise FocusingSpot Energy

VisuMax Femtosecond System

0.1 µJ

500 kHz

~1 µm


• Zeiss high performance optics key for optimum cut

▼low Numerical aperture high ▲▼large Spot diameter small ▲▼low Depth accuracy high ▲▼high Single pulse energy small ▲

VisuMax Femtosecond System



1. High Flap Thickness Reproducibility

2. Low Corneal Suction

3. Centration on the Corneal Vertex

4. Ultra Thin Flap

5. Flaps "Made to Measure"

6. Flaps in “Difficult” Eyes

7. Visual Outcomes

8. Future Potential: All-in-One


Assessment of VisuMax Flap Thickness

• 24 eyes treated with intended flap thickness of 110 µm• Central flap thickness measured by Artemis

J Refract Surg. Online Pre Release.


Artemis very high-frequency digital ultrasound arc-scanner

• Digital signal processing significantly reduces noise and enhances signal-to-noise ratio compared to analog signal processing

• doubles resolution• increase measurement precision by a factor of 3

• Thickness measurements made by computer-analysis of peaks on the I-scan trace – each peak provides a surface localization of 0.87 µm

• 3D layered pachymetry precision• Epithelium – 0.61 µm• Cornea – 0.74 µm• Flap – 1.14 µm

Surface localization:0.87 µm

ArcScan Inc Evergreen, Colorado


Flap Thickness Measurement

• 3D VHF digital ultrasound flap thickness measurement before and 3 months after treatment with Artemis I

+Pre-op

Post-op3 months

Epithelial thickness

Stromal Flap thickness

• Central flap thickness =

Thickness of the stromal component of the flap

measured 3 months after surgery

+ Preoperative epithelial thickness


Artemis B-Scan: 6 Months Post LASIK

Artemis B-Scan (above) of VisuMax Flap 6 months post LASIK. Edge detection by I-scan digital signal processing (red outline, below) based on raw scan data


RESULTS: Central Flap Thickness

Intended flap thickness = 110.00 µm

Average flap thickness = 112.31 µm

Accuracy = +2.31 µm

Precision (SD) = 7.89 µm

Minimum flap thickness = 102.61 µm

Maximum flap thickness = 132.94 µm

Range = 30.34 µm


RESULTS: Central Flap Thickness

• 25% of eyes within 2 µm of the intended flap thickness

• 54.2% of eyes within 5 µm of the intended flap thickness

• 87.5% of eyes within 10 µm of the intended flap thickness


Flap Thickness Reproducibility: PublishedAuthor Microkeratome Accuracy (µm) SD (µm) Pachymetry Method Pachymetry InstrumentStahl 2007 IntraLase FS60 +12.0 5.0 1 Mo Post-op OCT VisantePietila 2009 Femto LDV -20.0 5.0 Intra-op US SP-3000Alio 2008 IntraLase FS30 +6.0 6.2 1 Mo Post-op VHFU Artemis-2Hu 2007 IntraLase FS30 +13.9 7.1 3 Mo Post-op CMTF NRReinstein 2009 VisuMax +2.3 7.9 Pre and 3 Mo Post-op VHFU Artemis-1Li 2007 IntraLase (Pulsion) +35.0 9.0 1 Wk Post-op OCT CAS-OCTHolzer 2006 Femtec -0.4 9.1 Micrometer DigimaticSutton 2008 IntraLase FS30 -1.0 9.8 Intra-op US Corneo-Gage PlusBinder 2006 IntraLase FS10 +35.8 10.1 Intra-op US Cornea Scan II 50 MHzBinder 2006 IntraLase FS15 +21.1 10.2 Intra-op US Cornea Scan II 50 MHzHolzer 2006 Femtec +3.7 10.7 Micrometer DigimaticBinder 2006 IntraLase FS15 +25.8 10.8 Intra-op US Cornea Scan II 50 MHzSutton 2008 IntraLase FS15 +11.8 10.8 Intra-op US Corneo-Gage PlusLi 2007 IntraLase (Pulsion) +30.0 11.0 Intra-op US Corneo-Gage 2 50 MHzLi 2007 IntraLase (Pulsion) +36.0 11.0 1 Wk Post-op OCT CAS-OCT (Visante prototype)Holzer 2006 Femtec -7.9 11.1 Micrometer DigimaticHu 2007 IntraLase FS15 +16.8 11.1 3 Mo Post-op CMTF NRBinder 2006 IntraLase FS15 +20.1 11.8 Intra-op US Cornea Scan II 50 MHzBinder 2004 IntraLase FS +2.4 11.9 Intra-op US NRBinder 2004 IntraLase FS +15.0 12.0 Intra-op US NRTalamo 2006 IntraLase FS +9.0 12.0 Intra-op US Pachette IIBinder 2006 IntraLase FS10 +29.2 12.4 Intra-op US Cornea Scan II 50 MHzKim 2008 IntraLase FS60 +8.9 13.6 3 Mo Post-op OCT VisantePfaeffl 2008 IntraLase FS30 +0.4 13.6 Intra-op OCP Online OCPKezirian 2004 IntraLase FS -16.0 14.0 Intra-op US Pachette 50/60 KHz pachymeterBinder 2006 IntraLase FS10 +29.7 14.3 Intra-op US Cornea Scan II 50 MHzNeuhann 2008 IntraLase FS30 +11.7 14.7 Intra-op OCP Online OCPBinder 2006 IntraLase FS10 +17.4 15.2 Intra-op US Cornea Scan II 50 MHzBinder 2004 IntraLase FS -1.3 16.6 Intra-op US NRBinder 2006 IntraLase FS10 -0.4 17.1 Intra-op US Cornea Scan II 50 MHzKim 2008 IntraLase FS60 +4.8 17.6 3 Mo Post-op OCT VisanteBinder 2004 IntraLase FS -7.5 18.5 Intra-op US NRBinder 2006 IntraLase FS10 -9.4 19.0 Intra-op US Cornea Scan II 50 MHzLi 2007 IntraLase (Pulsion) +40.0 19.0 Intra-op US Corneo-Gage 2 50 MHzBinder 2006 IntraLase FS10 +13.4 22.1 Intra-op US Cornea Scan II 50 MHz

Two studies done with Artemis


Measurement Precision

Data Reproducibility

Validity of Measurement Instrument


90 95 100 105 110 115 120 125 130

Measured Flap Thickness

95% values within 2 standard deviations

90 95 100 105 110 115 120 125 130




90 95 100 105 110 115 120 125 130



90 95 100 105 110 115 120 125 130


Precision: 1 µm

95% within: 108-112 µm



90 95 100 105 110 115 120 125 130



90 95 100 105 110 115 120 125 130


Precision: 10 µm

95% within: 90-130 µm



95 104 105 106 114 115 116 125

Instrument 1

Value 1 Value 2

Instrument 2

Valid

Invalid





Required Precision: 2.5 µm

Reproducibility: 5 µm





Ideal Precision: 1.66 µm

Reproducibility: 5 µm



Artemis Flap Thickness Repeatability: 1.14 µm

Therefore, the Artemis is capable of measuring a flap thickness reproducibility of 7.89 µm as found in this study



Artemis Flap Thickness Repeatability: 1.14 µm

The Artemis is capable of measuring a flap thickness reproducibility as small as 3.42 µm







4. Ultra Thin Flap



7. Visual Outcomes



VisuMax Femtosecond System: Patient Comfort

Cross section of the contact glass• Spherical contact interface to cornea• Low corneal suction

– Minimal applanation– Minimal IOP increase– No vision loss during suction (data on file)

• “Out-to-in” femtosecond ablation– Fixation throughout flap creation


Comparison of typical curves plotted on the same scale

0

50

100

150

200

250

300

350

0 20 40 60 80 100

time (sec)

IOP

(m

mH

g)

IntraLase

VisuMax

IOP Comparison: VisuMax vs IntraLase

Ref: Grabner G. Femtosecond to fully replace microkeratome. Ophthalmology Times, 2008


0

50

100

150

200

250

300

350

0 20 40 60 80 100

time (sec)

IOP

(m

mH

g)

IntraLase

VisuMax Fast

VisuMax flap creation time VisuMax flap creation time reduced to reduced to ~20 seconds~20 seconds with software v 2.4.0with software v 2.4.0

IOP Comparison: VisuMax vs IntraLase

Comparison of typical curves plotted on the same scale

Ref: Grabner G. Femtosecond to fully replace microkeratome. Ophthalmology Times, 2008

Questionnaire: Patient Experience

VisuMax vs Hansatome


Questionnaire: Claustrophobia

Did you feel a sense of claustrophobia when the machine was maneuvered onto your eye?

58.3%

25.0%

16.7%15.4%

46.2%

30.8%

7.7%

0.0%0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

Perc

en

tag

e P

ati

en

ts

VisuMax [12] 58.3% 25.0% 16.7% 0.0%

Hansatome [13] 15.4% 46.2% 30.8% 7.7%

none at all not really a little a lot


Questionnaire: Discomfort from Pressure

What level of discomfort did you experience while the pressure was applied to the eye and the laser was used to create the flap (green light became

obscured)?

16.7%

41.7%

33.3%

0.0%

7.7%

30.8%

46.2%

7.7%

0.0%

8.3%

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

Perc

en

tag

e P

ati

en

ts

VisuMax [12] 16.7% 41.7% 33.3% 8.3% 0.0%

Hansatome [13] 7.7% 30.8% 46.2% 7.7% 0.0%

very comfortable

comfortable uncomfortablevery

uncomfortablepainful


Questionnaire: Length of Time With Pressure

How did you feel about the length of time that pressure was applied on the eye?

50.0%

41.7%

8.3%

15.4%

76.9%

7.7%

0.0%0.0%0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

Perc

en

tag

e P

ati

en

ts

VisuMax [12] 50.0% 41.7% 8.3% 0.0%

Hansatome [13] 15.4% 76.9% 7.7% 0.0%

quick not too long too long far too long






4. Ultra Thin Flap



7. Visual Outcomes



• Internal fixation target for patient – refraction corrected• Patient compliance• Auto centration on docking to contact glass – corneal vertex• Patient visualisation of the target throughout the procedure

VisuMax Femtosecond System: Centration


Flap Centration on Corneal Vertex


Flap Centration on Corneal Vertex

Corneal vertex

Flap edgeDye pooling in ablation zone






4. Ultra Thin Flap



7. Visual Outcomes



Ultra Thin Flap LASIK: No Need For PRK

• PRK Corneal Thickness Limit: 350 µm

• Alternative: Ultra Thin Flap LASIK– VisuMax Flap Thickness: 80 µm– Corneal Thickness: 350 µm– LASIK RST = 350 – 80 = 270 µm (>250 µm)

Flap thickness: 84 µm






4. Ultra Thin Flap



7. Visual Outcomes



Flap Creation with Previous PRK

Thick epithelium after hyperopic PRK

Flap underneath epithelium

Epithelium Post PRK for +3.00 D


Recutting Flaps: Measure Twice, Cut Once!

Incomplete Flap: Hansatome zero compression microkeratome



Second flap created under the half flap using the VisuMax femtosecond laser



• Original flap created in 1999• Measure Once: Artemis scan to measure flap thickness

Flap Thickness Profile



• Micro-bubble layer created with the VisuMax• Measure Twice: Artemis scan repeated before lifting the flap• Confirmed that the VisuMax flap was below original flap

VisuMax Micro-Bubble Layer Creation



• Flap lifted and ablation performed• Artemis scan 1 month post-op confirmed VisuMax flap below

original flap






4. Ultra Thin Flap



7. Visual Outcomes



VisuMax when Hansatome not Possible

Hansatome VisuMax

Forced to switch to PRK

Retreatment as VisuMax


VisuMax Flap in RK Patient


VisuMax Flap in Deep Lamellar Keratoplasty






4. Ultra Thin Flap



7. Visual Outcomes



VisuMax Population

• 232 eyes of 131 patients• Age

– median 38 years– range 21 to 68 years

• Spherical equivalent– mean -4.00 ± 1.86 D– range -0.13 to -8.63 D

• Cylinder– mean -0.72 ± 0.54 D– range 0.00 to -2.50 D

• BSCVA– 100% 20/20– 59% 20/16


Attempted vs Achieved: 6 MonthsAttempted vs. Achieved Spherical Equivalent

y = 0.9201x - 0.1442

R2 = 0.952

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

-9-8-7-6-5-4-3-2-10

Attempted Spherical Equivalent (Diopters)

Ach

ieve

d S

ph

eri

cal E

qu

iva

len

t (D

iop

ters

)


Accuracy 6 Months: Within Range of Intended

Accuracy: Within Range of Intended

0% 1%

15%

26%

13%

4%1% 0%

41%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Accuracy of Spherical Equivalent

Perc

en

tag

e E

yes

VisuMax [232] 0% 1% 15% 41% 26% 13% 4% 1% 0%

-2.00 To -1.51

-1.50 To -1.01

-1.00 To -0.51

-0.50 To -0.14

-0.13 To

0.13

0.14 To

+0.50

+0.51 To

+1.00

+1.01 To

+1.50

+1.51 To

+2.00


Efficacy 6 Months: Binocular Vision

Efficacy: Binocular UCVA

36%

75%

96%100% 100% 100%98%

0%

20%

40%

60%

80%

100%

Binocular UCVA

Perc

en

tag

e E

yes

Efficacy 36% 75% 96% 98% 100% 100% 100%

20/12.5 20/16 20/20 20/25 20/32 20/40 20/63


Efficacy 6 Months: Monocular Vision

Efficacy: Monocular UCVA

9%

59%

100% 100%

16%

62%

96%99% 100% 100%99%

0%

20%

40%

60%

80%

100%

Monocular UCVA

Perc

en

tag

e E

yes

Pre BSCVA 9% 59% 100% 100%

Efficacy 16% 62% 96% 99% 99% 100% 100%

20/12.5 20/16 20/20 20/25 20/32 20/40 20/63


Safety 6 Months: Lines Change BSCVA

Safety: Lines Change BSCVA

0.0% 0.0%3%

40%

2%

55%

0%

20%

40%

60%

Lines Change BSCVA

Perc

en

tag

e E

yes

Safety 0.0% 0.0% 3% 55% 40% 2%

Loss 3 or More

Loss 2 Loss 1 No Change Gain 1Gain 2 or

More


Stability: Change in Spherical Equivalent

Pre Op 1 Day 1 Month 3 Months 6 Months

Avg SEQ -4.06 +0.37 -0.08 -0.15 -0.17

SD SEQ 1.85 0.36 0.43 0.42 0.41

# eyes 232 228 223 203 222

Stability: Change in Spherical Equivalent

-7.00

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

Pre op 1 day 1 month 3 months 6 months

Time Point

Sp

heri

cal

Eq

uiv

ale

nt

(D)






4. Ultra Thin Flap



7. Visual Outcomes



VisuMax Unsurpassed Future Potential

• The new horizon of femtosecond technology in ophthalmology

• VisuMax is designed to become the corneal surgery workstation for a large spectrum of procedure options

• Unprecedented accuracy in corneal incisions– eg Femtosecond lenticule extraction (FLEx)



Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4

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

Thank You

Comparison with IntraLase


IntraLase Claims vs VisuMax

• Lack of clinical data• Few “champion” users• Instability• Curved glass can't work properly• IOP• Flap diameter• No recentration software• Can't do oval flap• Can't do ICRS• Faster?




• Reinstein et al– Accuracy and Reproducibility of Central

Flap Thickness and Visual Outcomes of LASIK with the VisuMax Femtosecond Laser System and the MEL80 Excimer Laser

– JRS [Online]

• Blum et al– LASIK for Myopia Using the Zeiss

VisuMax Femtosecond Laser and MEL 80 Excimer Laser

– JRS [Online]

• Sekundo et al– First efficacy and safety study of

femtosecond lenticule extraction for the correction of myopia Six-month results

– JRS Sept 2008




• Dan Reinstein• So what? It’s just newer!




• Instability and crashes have been ironed out since the prototype




• Curved glass is auto-calibrated for each lens




• IOP has been shown to be lower for VisuMax than IntraLase (Grabner)– VisuMax: 84 mmHg– IntraLase: 180 mmHg

• IOP raised for shorter duration– VisuMax: ~30 seconds– IntraLase: ~80 seconds

• Patient can see during procedure




• Reinstein data showed achieved flap diameter 0.50 mm greater than displayed

• Recentration with IntraLase reduces flap diameter




• Not required as VisuMax auto-centrates on the corneal vertex




• Why do you need an oval flap?• Induce astigmatism?



• Lack of clinical data• Few “champion” users• Instability• Curved glass can't work properly• IOP• Flap diameter• No recentration software• Can't do oval flap• Can't do ICRS• Faster? • ICRS settings in the pipeline

along with graft, AK etc




• Total time for IntraLase is longer– Ring segment placement– Docking of lens– Ablation

the great femtosecond face-off: carl zeiss meditec visumax

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