Femtosecond Laser-Assisted Implantation of Toric Multifocal IOL Based on Automated Corneal Shape Analysis – Comparison with a Manual Technique, presented at ASCRS 2018 – by Philipp Hagen, D. Breyer, H. Kaymak, K. Klabe, T. Ax, F. Kretz, G. Auffarth

1. Breyer, Kaymak & Klabe Eye Surgery and Premium Eyes are Consulting, Study Center & MAB for:
Abott, Alcon, AlimeraSciences, Allergan, AMO, Bayer, Carl Zeiss Meditec, Ellex, Fluoron, Geuder,
iOptics, LensAR, Medicem, Novartis, Oculentis, Oertli, Revision Optics, Santen, Staar Surgical,
Sifi Medtech, Thea, Topcon, Visufarma, Ziemer
Femtosecond Laser-Assisted Implantation of Toric Multifocal IOL
Based on Automated Corneal Shape Analysis –
Comparison with a Manual Technique
Philipp Hagen, Detlev Breyer, Hakan Kaymak, Karsten Klabe, Timon Ax, Florian Kretz, Gerd Auffarth

2. Financial Disclosure
Breyer, Kaymak & Klabe Eye Surgery and Premium Eyes are Consulting, Study Center & MAB for:
Abott, Alcon, AlimeraSciences, Allergan, AMO, Bayer, Carl Zeiss Meditec, Ellex, Fluoron,
Geuder, iOptics, LensAR, Medicem, Novartis, Oculentis, Oertli, Revision Optics,
Santen, Staar Surgical, Sifi Medtech, Thea, Topcon, Visufarma, Ziemer

3. Motivation
• IntelliAxis™-System for LENSAR eases axis alignment of toric IOLs
• Idea for retrospective data analysis:
For toric IOLs: Analyze astigmatic correction in IntelliAxis™ group and compare results to those of
group with manual axis alignment
• Patient selection for both groups:
all eyes (consecutive cases, no exceptioon) with
 cataract surgery or RLE using
 LENSAR femtosecondlaser followed by phacoemulsification and
 implantation of toric IOL:
Lentis LS-313 MF15, MF20, MF30 or AT LISA tri 939
• Vector analysis of astigmatic correction via
Alpins method

4. Why is precise axis alignment important?
• Astigmatism of type (Z, α) is corrected by (Z, α+90°).
Assumption: Correction is performed with small angular error δ:
• Connection to Angle of Error:
Gaussian error propagation:
For small angular axis
errors δ holds
rule of thumb:
Per 1° of error, approx.
3.5% of remains
uncorrected!
Sample calculation:
Axis error: δ = 7°= AE
 IS = 24.4%
 Residual postop. cyl.
of -0.5 D in case of
preop. cylinder of -2.0 D!
High precision (δ ≈ 0°)
advantageous for
effective reduction of
astigmatism

5. Materials and Methods: Axis Alignment
Procedure for axis alignment of marks of Comfort MF15 toric
Manual IntelliAxis™
Determine steepest axis:
Scheimpflug tomography (Pentacam) &
Aberrometrie (KR-1W)
Bestimmung der steilsten Achse:
Corneale Topografie (Cassini) relativ zur Iris
Set 2 corneal horizontal marks with YAG-Laser
Daten werden über Cloud (Streamline) an LENSAR
übertragen
LENSAR kompensiert Zyklorotation durch Abgleich der
Irisbilder
LENSAR markiert steilste Achse durch 2 corneale
Laserspots
Lens fragmentation and capsulorhexis performed by LENSAR
Phacoemulsification and implantation of toric MIOL
Adjust steepest axis on STACY protractor
Ausrichtung der torischen MIOL-Achse anhand der
LENSAR-Markierungen
Align STACY protractor with horizontal corneal
YAG-marks using the surgery monitor
Align toric IOL-axis according to steepest axis on STACY

6. Materials and Methods: Axis Alignment
Procedure for axis alignment of marks of Comfort MF15 toric
Manuell IntelliAxis™
Bestimmung der steilsten Achse:
Aberrometrie (KR-1W) oder Scheimpflug Tomografie
(Pentacam)
Determine steepest axis:
Corneal Topography (Cassini) relative to iris
Setzen von 2 Horizontalmarkierung auf Cornea mittels
YAG-Laser
Data is transferred to LENSAR via cloud solution
(streamline)
LENSAR compensates cyclorotation via matching of iris
structures
LENSAR marks steepest axis by setting 2 opposing corneal
laser spots
Lens fragmentation and capsulorhexis performed by LENSAR
Phacoemulsification and implantation of toric MIOL
Einstellen der steilsten Achse auf STACY
Winkelschablone
Align toric axis of MIOL using LENSAR marks
Ausrichtung der STACY Winkelschablone am OP-Monitor
mittels kornealen YAG-Horizontalmarkierungen
Ausrichtung der IOL-Achse anhand der steilsten Achse auf
Schablone

7. Materials and Methods: Axis Alignment
Procedure for axis alignment of marks of Comfort MF15 toric
Manual IntelliAxis™
Determine steepest axis:
Scheimpflug tomography (Pentacam) &
Aberrometrie (KR-1W)
Determine steepest axis:
Corneal Topography (Cassini) relative to iris
Set 2 corneal horizontal marks with YAG-Laser
Data is transferred to LENSAR via cloud solution
(streamline)
LENSAR compensates cyclorotation via matching of iris
structures
LENSAR marks steepest axis by setting 2 opposing corneal
laser spots
Lens fragmentation and capsulorhexis performed by LENSAR
Phacoemulsification and implantation of toric MIOL
Adjust steepest axis on STACY protractor
Align toric axis of MIOL using LENSAR marks
Align STACY protractor with horizontal corneal
YAG-marks using the surgery monitor
Align toric IOL-axis according to steepest axis on STACY
4 x manual axis
alignment
1 x manual axis
alignment
1
1
2
3
4
Estimated precision of alignment: ~3°
Expectation:
less scattering in
IntelliAxis™ group

8. Materials and Methods: Preoperative Patient Data
Group Manual IntelliAxis™
Number of
Eyes 69 88
CAT-OP 51 47
RLE 18 41
Ratio M:F [%] 42:58 36:64
Mean ±
SD
Age [years] 62 ± 13 60 ± 11
Spherical Equivalent
(SE) [D]
-1.8 ± 4.5 -2.1 ± 5.0
Corneal Cylinder [D] -1.5 ± 0.5 -1.6 ± 0.7
IOL-SE [D] 18.7 ± 5.3 19.0 ± 6.4
IOL-Cylinder [D] 2.1 ± 0.7 2.2 ± 1.0
No significant (p<0,05)
differences

9. 0%
25%
50%
75%
100%
[0,0.25)
[0.25,0.5)
[0.5,0.75)
[0.75,1)
[1,1.25)
[1.25,1.5)
[1.5,2)
[2,3)
[3,oo)
Percentageofeyes[%]
2*|J|=|Cylinder| [D] within interval
Astigmatism
Results: Astigmatism
Group
|C| [D]
# m ∆
Manual (pre) 69 1.50 0.52
IntelliAxis™ (pre) 88 1.56 0.71
Manual (post) 69 0.44 0.35
IntelliAxis™ (post) 88 0.36 0.38
# = number
m = mean
∆ = standard deviation
SE = standard error of mean
• Effective reduction of astigmatism in both groups
• No significant (p<0.05) differences between both groups

10. Summary
• Effective correction of astigmatism with both methods:
• No signifcant differences between mean values of
- Angle of Error
- Difference Vector
- Correction Index
- Index of Success
• IntelliAxis™ group:
- DV, CI and IS closer to ideal values
- Slightly less scattering
 Tendency towards slight advantages regarding precision for IntelliAxis™
In agreement with
prediction 
Group #
Angle of Error AE [°] Difference Vector |DV| [D] Corretion Index CI Index of Success IS
m ∆ SE m ∆ SE m ∆ SE m ∆ SE
Manual 69 0.6 8.5 1.0 0.44 0.35 0.04 1.08 0.32 0.04 0.31 0.30 0.04
IntelliAxis™ 88 2.7 8.3 0.9 0.36 0.38 0.04 1.03 0.22 0.02 0.26 0.27 0.03
# = number, m = mean, ∆ = standard deviation, SE = standard error of mean
Advantages for patient management
regarding…
Manual IntelliAxis™
…axis alignment
- YAG shots recognized by patient
- compliance required
+ LensAR marks integrated in the
surgery and not recognized
…discussion of visual outcome
+ potential human mistakes have
been reduced

11. Questions & Outlook
• Can this tendency be confirmed for larger data sets?
• Potential error sources (selection):
o Preoperative:
 Measurement accuracy of anterior + posterior = total corneal cylinder
 How good is eye model & theoretical calculation formula for IOL cylinder?
 IOL cylinder power is usually not custom-fit since it is manufactured with certain step width
o Surgery:
 How big is the corneal astigmatism that is (unintentionally) induced due to surgery?
 How good are IOL centration and IOL alignment?
o Postoperative:
 How stable are centration and alignment?
 How precise can the residual cylinder be measured via phoropter?
Considered in this analysis

12. Questions & Outlook
Fundamental issues:
• MIOL / EDOF:
What is the threshold for a
„bothering“ residual
astigmatism?
• Monofocal IOL:
Small residual astigmatism
(WTR, ≲ 0.5 D) beneficial for
depth of focus?

13. Thank you very much for your attention!
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