Revolution, Evolution, or No Solution?
Making Sense of the Literature
Ken Lipstock, M.D.
Richmond, Virginia
emtosecond laser provides an ultrafast burst of energy.
•Argon, excimer, and Nd: YAG lasers: nanosecond (10 -9 ) pulses
•Femtosecond: 10 -15 second
•Excimer: “photoablates”
•Argon: “photocoagulates”
•Nd: YAG and Femtosecond: “photodisrupt”. Their light
energy can be absorbed by optically clear tissue and create
“microcavitation bubbles” that cause an acoustic shock wave
that incises the target tissue.
Femtosecond laser’s ultrafast pulse
allows smaller amounts of energy to
provide similar power output to the
NdYag. This results in much smaller
cavitation bubbles therefore reduced
“collateral damage” to adjacent tissues.
Femtosecond laser first FDA approved for LASIK flaps
in 2001 and then approved for cataract surgery in 2010.
With guidance systems (OCT or Scheimpflug-like
technology) it is used to make:
 Cataract clear corneal incisions and limbal
relaxing incisions
 Capsulorhexis
Lens fragmentation/softening; a pretreatment prior to
phacoemulcification and/or irrigation/aspiration.
Mistrust but Verify
We are witnessing one of the most intense marketing campaigns ever in Ophthalmology.
“It has automated, computer-guided laser precision with minimal collateral tissue
damage......with emerging evidence of ......greater precision and accuracy of the
anterior capsulotomy, and more stable and predictable positioning of the
intraocular lens.”
And this is a sentence from a scientific study in a respected peer reviewed
journal!
Is Femtolaser Cataract Surgery “the most important evolution since the
transition to phacoemulsification?”
Much has been claimed but how much is substantiated?
In the following presentation I will review the literature to try to shed some
light on the subject. Since the vast majority of journal articles are written
by those with financial ties to the femtosecond companies, the authors of
the journal articles will be color coded red for financial ties and green if
not. (The lead author will be in red if at least one of the authors has
financial ties.)
Company
Mode of docking
Imaging
LensSx
Alcon, Ca.
Curved glass at
first, now uses soft
contact interface
OCT
LensAR
Privately Held
Orlando, Fl.
2 piece non
contact interface
Scheimpflug-like
Catalys
AMO, Ca.
Liquid-optics
interface
OCT
Victus
B&L
Curved glass
interface
OCT
Capsulorhexis
Hypothesis:
a capsulorhexis (rhexis) should overlap the IOL optic approximately .5 mm
symmetrically 360 degrees and be larger than 4 mm . This will give a better and more
consistent effective lens position (ELP) because of less asymmetric contractile force
from the fibrosing anterior capsule on the IOL. The IOL should then not position more
anteriorly or posteriorly than anticipated or with decentration or tilt. 1,2,3
A better ELP leads to:
1. Closer to targeted spherical equivalent and less cylinder
a. Better uncorrected distance vision (UCDVA)
2. Less higher order aberrations like spherical aberration and tilt
a. Better corrected distance vision (CDVA)
b. Better quality of vision with less glare, halos, and better
contrast sensitivity.
Claim of the Femtolaser
Companies:
CCC vs. Femto Buttons
The femto anterior capsulotomy is more
precise (consistent) and more accurate than a
manual curvilinear capsulorhexis (CCC).
Better size, more circular, better centered
thus better overlap of the IOL. And better
overlap yields less IOL decentration and tilt
and better anterior-posterior position.
Assymetric Overlap
Decentered IOL
4,5
Friedman; JCRS; 2011
4
Kranitz; JRS; 2011
5
 Continuous curvilinear capsulorhexis (CCC) technique was developed
6,7
simultaneously by Neuhann in Germany and Gimbel in Canada around 1987.
 Prior rhexis techniques (eg. can opener) led to 100% anterior capsular tears
8
during cataract surgery and CCC tear rate approached 0%.
 Prior to CCC capsular tears led to IOL’s with haptics commonly with one in
the bag and one in the sulcus or with both in the sulcus.
Continuous Curvilinear Capsulotomy:
A Revolutionary Change for IOL Positioning
9
Assia, Apple (Oph 1993) showed:
 Bag-Sulcus Fixation mean Decentration= .64 ± .39mm (range up
to 1.76mm)
Note: 1 SD =66.6% thus:
1.0mm decentration was common
 Bag-bag Fixation mean Decentration= .18 ± .09
Clinical Studies in the CCC Era Measuring IOL Decentration and Tilt
IOL
Mean dec.
Mean tilt
0.15
1.1
MZ60BD
0.27 ± .15
2.62 ± 1.33
SI30NB
.30 ± .16
2.53 ± 1.36
MA60BM
.30 ± .15
2.71 ± 1.84
0.28 ± .14
2.83 ± .89
MZ60BD
0.31 ± .15
2.67 ± .84
SI-30NB
0.32 ± .18
2.61 ± .83
AcrySof MA60BM
0.33 ± .19
2.69 ± .87
AcrySof MA30BA
0.30 ± .17
3.43 ± 1.55
CeeOn 911A
0.24 ± .13
3.03 ± 1.79
PhacoFlex SI-40
0.23 ± .13
3.26 ± 1.69
CeeOn 911A
0.29 ± .21
2.34 ± 1.81
AcrySof MA60BM
0.24 ± .10
2.32 ± 1.41
AcrySof SA30AL
0.34 ± .08
2.70 ± .55
AcrySof MA30BA
0.39 ± .13
2.72 ± .84
Rosales (2006)
UNKNOWN
0.25 ± .28
.87 ± 2.16
de Castro
UNKNOWN
0.34 ± .19
2.34 ± .97
AR40C
0.19 ± .12
2.89 ± 1.46
Z9000
0.27 ± .16
2.85 ± 1.36
H60M
0.25 ± .17
4.88 ± 1.45
MA60BM
0.28 ± .16
4.85 ± 1.52
Akkin (1994)
Hayashi (1997)
Mutlu (1998)
Kim (2001)
Mean follow-up=
12.2 months
Range= 3 to 48
months
Taketani (2004)
Baumeister (2005)
Mutlu (2005)
Baumeister (2009)
Hayashi (2014)
Mean IOL decentration 0.28 ± .16 mm and tilt 2.61 ± 1.2°
10
How Much Does 0.28 ± .16mm Decentration and 2.6° ± 1.2° Tilt
Effect Vision?
Would even less decentration and tilt provide better UCVA and CDVA?
Would even less decentration and tilt provide better contrast
sensitivity and less glare and halos?
Would even less decentration and tilt have more or less effect depending on
whether the IOL is spherical, negative aspheric, neutral aspheric, accommodating,
multifocal?
Let`s look at the Non-Femto Literature first….
Remember: Femto Companies Claim
Better Rhexis → Better ELP → Better Vision
Better Vision can mean both smaller refractive error and better quality of CDVA.
Okada has shown that a better rhexis does NOT lead to a Smaller Refractive Error
(spherical equivalent or cylinder.)
11
Okada (Oph 2014) : Does the Rhexis Circularity or Centration effect Post-op
Refractive Error?
 93 eyes
 Phaco mostly by residents
 Pre-op spherical equivalent -7.75 to +4.50
 Alcon Spherical IOL (SN60AT)
Results for One Month and 1 year
Measurements:
 Rhexis Circularity (comparison to
perfect circle; ratio 1.0=perfect)
 Rhexis (not IOL) Decentration from
pupil center
 Complete Overlap of Rhexis
(360 over the IOL Optic) yes or no
Okada Results (Cont’d):
(Stabilization
Change from 1 Month to 1 Year)
 from 1 month – 1 year
1 Month
1 Year
mean
mean
Circularity
.83 ± .01
.87 ± .03
p < .001
Decentration
(mm)
.30 ± .14
.23 ± .13
p < .001
360° overlap (% of
eyes)
88%
90%
p = .02
Over time the rhexis became more circular, less decentered and with more
overlap.
Okada Results (Cont’d)
Circularity of Rhexis
 NO significant correlation of circularity with post-op target spherical
equivalent at 1 month or 1 year
 NO significant correlation of circularity with post-op cylinder at 1
month or 1 year
Okada Results (Cont’d)
Decentration of Rhexis
NO correlation with change in cylinder from 1 month to 1 year. It did correlate with
the change in spherical equivalent between 1 month and 1 year (p=.03).
But Bottom Line:
NO significant correlation of Decentration with post-op target
spherical equivalent at 1 month or 1 year.
 NO significant correlation of Decentration with post-op
cylinder at 1 month or 1 year.
Okada Results (Cont’d)
360° Overlap vs. Incomplete Overlap
→ NO correlation with change in spherical equivalent between 1 month and 1 year. It
did correlate with change in cylinder between 1 month and 1 year.
But Bottom Line:
 NO significant correlation of Overlap with post-op target
spherical equivalent at 1 month and 1 year
NO significant correlation of Overlap with post-op cylinder at 1
month and 1 year
Conclusion:
 Rhexis Centration and Circularity and
Overlap do not correlate with Post-op Refractive
error.
 Rhexis Centration and Overlap do play some
role in stability of refraction but not enough to
effect the average post-op refractive error at one
year.
Effect of IOL Position on Quality of Vision
Remember, Femto companies hypothesize: Better Overlap → Better IOL
Position → Better Vision
Okada’s Study Showed: Better Overlap Does Not → Better Refractive Error
Question: Could Better Overlap → Better Quality of Vision
Lower order Aberrations: myopia, hyperopia, astigmatism
Higher Order Aberrations (HOA’s): coma, spherical aberration, trefoil, etc. can
effect the quality of vision. These are measured with a wavefront analyzer.
Decentration and Tilt may effect Aspheric IOL’s more than spherical IOL’s so we
will spend some time reviewing this subject now.
Effect of IOL Position on Quality of Vision (Cont’d)
Remember this:
The larger the pupil the more HOA’s there are.
The pupil size increases in dim light and decreases with age.
 55 years old (cataract age) pupil diameter:
Bright mesopic= 3.2mm
Mesopic=
4.0mm
Low Mesopic=
5.0mm 12
Effect of IOL Position on Quality of Vision (Cont’d)
Aspheric IOL’s
 The First Negative Aspheric IOL was Tecnis (Pharmacia now AMO). Holladay
and Piers did the early theoretical research for Pharmacia.
Basic Idea:
A. The amount of total eye spherical aberration could be manipulated with
an IOL because spherical aberration unlike other HOA`s like coma and
trefoil is not very sensitive to the position of the IOL (rotation,
decentration and tilt). However decentration and tilt could still possibly
effect the results.
B. The cornea has positive asphericity and this is stable despite aging. It is
approximately +.27. The lens has negative asphericity to balance the cornea
so the total eye spherical aberration is minimized. The lens becomes more
positively aspheric after age 40 causing more total eye positive asphericity.
41 y.o. 6.0mm pupil mean s.a.=.10
13
65 y.o. 6.0 pupil mean s.a=.19
A spherical IOL has positive asphericity which increases
the spherical aberration of the eye.
Pharmacia developed a -.27 negative aspheric IOL (Tecnis) to
eliminate total eye spherical aberration and thereby improve
the quality of vision eg., contrast sensitivity. Tilt and
decentration can induce HOA`s but much more in a negative
aspheric IOL than a spherical IOL.
Question: Would tilt and decentration be a problem with
negative aspheric IOL`s?
14
Holladay and Piers (JRS 2002)
They calculated the Modular Transfer Function (MTF) at different amounts of tilt and
decentration. MTF is a mathematical/theoretical calculation of contrast (the contrast
of an image relative to the contrast of the object traveling through an optical medium).
This relates to quality of vision.
Amount of tilt and decentration of Tecnis where the MTF (quality of vision) becomes
worse than a spherical IOL:
Decentration= 4mm
Tilt= 7°
Holladay used monochromatic light for his calculations. In 2007 Piers corrected the
calculations based on the more physiologic polychromatic light we experience:
Decentration= .8mm
Tilt= 10°
Compare to 0.28 ± .16mm actual mean decentration of IOL’s with a
CCC
15
Compare to 2.6 ± 1.2° actual mean tilt of IOL’s with a CCC
Piers’ Graph
l
a
w
l
e
s
s
Polychromatic MTF
Polychromatic MTF
l
a
w
l
e
s
s
.28
.44
0.8
Decentration
Decentration .28 ± .16 → .44mm
Note: Minimal effect on MTF for most
patients.
3.8°
10°
2.6°
Tilt
Tilt 2.6 ± 1.2° → 3.8°
Note: Tilt effects MTF even less than
decentration.
Ignore top dotted line (theoretical IOL with all HOA’s corrected)
Solid line= Tecnis
Dashed line= Spherical IOL
16
Aspheric IOL Clinical Studies
Kohnen`s team in Germany
17,18,19
A series of intraindividual studies (same patient with one eye
spherical IOL and other eye Tecnis).
1. Spherical aberration was less with Tecnis at all pupil sizes (the bigger the
pupil the larger the difference).
2. Total HOA`s were lower with Tecnis only if pupil  6.0 mm (most
cataract patients’ pupils are smaller) and coma and trefoil were no
different at all pupil sizes.
3. Even though spherical aberration was less, Tecnis gave no
improvement in CDVA photopic with high contrast charts
or mesopic low contrast charts.
4. Tecnis gave no improvement in Contrast Sensitivity
photopic or mesopic.
Kohnen (Cont’d)
5. Were these less than expected results with Tecnis due to tilt and decentration?
a) The Kohnen group measured it:
Tecnis: decentration= 0.27 ± .16mm (as expected from other studies)
tilt= 2.9 ± 1.5° (as expected from other studies)
(Decentration and Tilt of Spherical IOL’s studied were almost exactly the
same.)
b) Multiple Regression Analysis showed no statistically significant correlation
between decentration or tilt with the HOA’s. ie, Decentration and Tilt were
not the reason why Tecnis performed worse than expected.
c) This is consistent with the Piers graphs: Decentration and Tilt with a CCC are
too small to significantly effect HOA’s even with negative aspheric IOL’s.
So why didn’t Tecnis eyes see better? They had significantly less spherical
aberration and we know decentration and tilt were too small to effect that
impact. Puzzling….
Possible explanations:
a) Pupil size: average pupil in the study in mesopic conditions was
3.8mm. Negative spherical correcting IOL’s have a much larger effect
in pupils  6.0mm.
b) Interactions with other HOA’s. It is not just spherical
aberration we are dealing with. Some HOA’s may interact with others
in a negative or positive way. 20
Take home message:
 Factors effecting quality of vision are complex. (Marketing companies may
use that to their advantage.)
 Negative aspheric IOL’s are not significantly effected by decentration and
tilt for most patients.
Neutral Aspheric IOL Studies
Developed Several Years Later
Concept
1. Do not add or subtract from the total eye
spherical aberration.
2. Neutral aspheric IOL’s may not actually
decrease the total eye spherical aberration but
they are less effected by decentration and tilt than
negative spherical IOL’s.
Spheric
Modulation
Neutral
Apheric
Eppig (JCRS 2009) 21
Modulation
.4
.4
.4
Modulation
Soft Port
Modulation
.4
Modulation
Negative
Aspheric
Modulation
Tecnis
21
 Model Eye Study calculation of MTF with Decentration; comparing Aspheric, Neutral Aspheric, & Spherical
IOL’s.
Two pupil sizes and three types of IOL’s.
 Verticle lines = .3 and .4mm decentration from the literature. (Mean and with one standard deviation.)
 Monochromatic light (Holladay) was used. Slope should be less narrow as per Piers/ Polychromatic light.
Decentration has no effect on neutral aspheric and spherical IOL..
 Tecnis is more beneficial in larger pupil.
22
Tilt has minimal effect on Tecnis even with
monochromatic MTF calculations.
23
Johansson (JCRS 2007)
Swedish Multicenter Double masked study of 80 patients with Tecnis in
one eye and Neutral aspheric Akreos in the other.
Results (3 months post-op):
 Total HOA`s less for Tecnis for 4, 5 and 6mm pupils (p <.01)
 Spherical Aberration less for Tecnis for all pupils (p<.o001)
Nevertheless:
 No difference in CDVA mesopic and photopic with high or low contrast
charts.
 No difference in contrast sensitivity mesopic or photopic
 Depth of field better with Acreos (p=.002)
Patient Questionnaire: Subjective Visual Quality:
Preferred Akreos 2X more (p<.001)
Complaints of Visual disturbances Tecnis 3X more (p<.001)
Why was vision no better with Tecnis than Neutral Aspheric even though
Tecnis had decreased HOA’s in this study?
Remember:
Kohnen showed vision no better with Tecnis than Spherical
IOL. They suggested (1) Small mean pupil size in cataract
population. (2) Interplay of HOA’s.
Johansson suggests for neutral aspheric comparison
1. Better depth of field with neutral aspheric
2. Different IOL design/material
Things We Have Learned So Far:
 Decentration and Tilt have only minor effect on Negative Spherical
IOL’s and even less on Neutral Aspheric and Spherical IOL’s.
Factors Effecting Quality of Vision are Complex.
 Negative Aspheric IOL’s may not perform any better than Spherical
IOL’s.
 Neutral Aspheric IOL’s may perform better than Negative Aspheric
IOL’s.
 Femto Companies Suggest that better IOL Centration and Tilt Improves
Vision with All IOL’s but Especially with Aspheric IOL’s, Multifocal IOL’s,
and Accomodating IOL’s.
Now you have the background to better evaluate such claims pro or con.
How Much Does 0.28 ± .16 Decentration and 2.6° ± 1.2° Tilt Effect Vision?
Not much.
Would even less decentration and tilt provide better UCVA and CDVA?
Would even less decentration and tilt provide better contrast sensitivity and less
glare and halos?
Would even less decentration and tilt have more or less effect depending on
whether the IOL is spherical, negative aspheric, neutral aspheric, accomodating,
multifocal?
Probably Not.
Let`s See What the Femto Literature Has to Say….
CCC vs. Femto Buttons
Assymetric Overlap
Decentered IOL
4
4
5
5
Claim of the Femtolaser Companies:
Better Rhexis → Better ELP → Better Vision
Studies: Rhexis, Size, Shape, Centration:
Femto vs. Phaco
Names in
Red= Financial Ties
Green= No Financial Ties
Study
Eyes
Femto Laser
Post-op
Size
Circularity
Overlap
(1=perfect)
Nagy
24
(2009)
25
Planker
(2010)*
Tackman
LenSx
30 Femto
30 Phaco
Catalys
26
27
54 Femto
57 Phaco
(2011)*
28
Kranitz
(2011)*
Friedman 29
Reddy
20 Femto
20 Phaco
39 Femto
24 Phaco
(2011)*
30
2013*
* Human Eye
Studies
1 wk
Target 5.0
Femto better: 5.02mm vs. 5.88mm
p<.001
49 Femto
24 CCC
(2011)*
Nagy
5 pig
eyes
56 Femto
63 Phaco
Intraop
specimens
Lensar
Intraop
specimens
LenSx
1 wk
Difference from target diameter:
Femto: .027mm ± .03
CCC: .282 ± .30
p<.001
Femto: 0.95 ± .04
CCC: 0.77 ± .15
p<.001
Difference from target diameter:
Femto: 0.16 ± .17mm
CCC: 0.42 ± .54
p<.001
Femto better p=.032
Incomplete:
Femto 11%
CCC 28%
p=.033
LenSx
Catalys
1yr post-op
Intraop
specimen
No significant
difference at 1mo
and 1yr
Difference from target diameter:
Femto: .029 ± .026
Phaco: .337 ± .26
p<.05
Victus
Inraop
specimen
Femto better at 1mo
and 1yr
p<.05
Femto: .94 ± .04
Phaco: .80 ± .15
p<.05
Femto better
Femto better
p<.01
p<.01
Capsule centration
Femto better
p<.01
Femto → Rounder, Better Size and Centration → Better Overlap
Does a better Femto Rhexis Yield Better results?
Kranitz (surgeon Nagy)LenSx (JRS 2011) 31
 20 Femto Human vs. 20 Phaco Cases
 Decentration of the IOL was better with Femto at 1 month and 1 year
At 1 year femto .15mm ± .12 and Phaco .30mm ± .16 (p<.05)
This is comparing spherical IOL’s.
Remember the Piers Graph for Aspherics?
Piers’ Graph
Even for Asheric IOL’s the
Difference between 0.15mm
and 0.3mm is minor.
It doesn’t mean much.
0.30
0.15
16
Kranitz (cont’d)
Effect of Decentration on Neutral Aspheric and Spherical IOL’s.
Softport AO
Neutral
Aspheric
Eppig Graph
It doesn’t mean ANYTHING.
Softport AO
Spherical
Mihaltz (surgeon Nagy) LenSx (JRS 2001)
32
48 Femto and 51 Phaco Cases with Spherical IOL`s.
6 Month Post-op Refractive Error and HOA’s
No Difference in Refractive Error:
 Deviation from Intended spherical equivalent (p>.05)
 Amount of Cylinder and UDVA and CDVA (p>.05)
Ocular Higher Order Aberrations (4.5 virtual pupil):
 No Difference in any HOA`s.
 MTF (theoretical quality of vision calculated from the contrast
sensitivity calculated from the HOA`s) better for Femto (p<.05) even
though there was no significant difference in HOA’s between Femto and
Phaco with Spherical IOL’s
33
Kranitz (surgeon Nagy) (JRS 2012)
LenSx 20 Femto and 25 Phaco Cases with Spherical IOL`s.
Measured IOL Tilt and Decentration
 Femto Tilt: 2.2° ± 1.4° Note: 4.3° tilt with Phaco IOL’s
than the mean tilt in
Phaco Tilt: 4.3° ± 2.4° is higher
the literature (.26° ± .12°).
Femto better (p=.001)
 Femto Decentration: 0.23 ± .11mm (this is close to literature decentration of 0.28)
Phaco Decentration: 0.33 ± .17mm
Femto better (p=.02)
 UCDVA No Difference
 Deviation from Target Refraction no significant Difference
Eppig Graph
CDVA Femto better at 1 month and 1 year (p-.03 and .04
respectively). (Only Study even among Red
Neutral
Aspheric
highlighted ones with this result)
Kranitz Explanation for
Better CDVA: Tilt Correlated
With CDVA
Really?
Spherical
Filkorn (surgeon Nagy)(JRS 2012)
34
LenSx Femto 77 and Phaco 57 Cases with Spherical IOL`s.
3 Month Post-op Refractive Error
(Included -20D to +7D pre-op )
 Deviation from Target spherical equivalent
Femto: .12D better that Phaco (p=.04) (Only study reporting
better spherical equivalent).
 CDVA No Difference
Lawless
35
61 Femto and 29 Phaco All Restor Multifocals
No Significant Difference Even In a Multifocal Where Centration Should
Be Most Significant:
Deviation from Target spherical equivalent: No Difference
Amount of cylinder : No Difference
UDVA, CDVA, UNVA: No Difference
Note Deviation from Spherical Equivalent Target
Femto: 0.26 ± .25 (range -.10 to 1.18)
Phaco: 0.23 ± .16 (0 to .52).
p=.54
But….
Lawless (cont’d)
Deviation from Targeted Spherical Equivalent
Femto
Standard Deviation ± .39
Range -.75 to +1.25
Phaco
Standard Deviation ± .32
Range -.50 to +1.75
LESS SCATTER, SMALLER SD AND RANGE WITH PHACO
Abe11 36
100 Femto and 100 Phaco
3 week post-op  No difference between Femto and
Phaco in Deviation from target spherical equivalent
or CDVA
z
z
Femto vs. Phaco Vision
32
33
rn
s
6
35
34
# Femto
Eyes
IOL Type
# Phaco Deviation
Eyes
from Target
Spherical
Equiv.
Cylinder
UDVA
48
Spherical
51
No Diff.
No Diff. No. Diff.
20
Spherical
25
77
Spherical
57
Femto .12D
better
(p=.04)
61
Multifocal
29
No Diff.
100
Spherical
100
No. Diff
No Diff.
No Diff.
CDVA
UN
Femto better at
1mo. & 1yr.
(p=.03 & .04
respectively)
No Diff.
No Diff.
No Diff.
only study even among the red with this result
No Diff.
No Diff.
No
Remember this Question?
How Much Does 0.28 ± .16 Decentration and 2.6° ± 1.2° Tilt Effect Vision?
Would even less decentration and tilt with Femto provide better UCVA and
CDVA? Answer: No.
Would it provide better contrast sensitivity and less glare and halos?
No studies to date have tested this. …Why not?
Why no intraindividual comparison of Femto and Phaco and measuring
mesopic vision on low contrast charts (most sensitive visual acuity test
for visual quality), or measuring contrast sensitivity photopic,mesopic
with and without glare? Why no patient questionnaires as to which eye
they like better?
Would less decentration and tilt with Femto have more or less effect
depending on whether the IOL is spherical, negative aspheric, neutral
aspheric, accomodating, or multifocal?
The studies to date have tested Femto vs. Phaco with Spherical IOL’s and a
Multifocal.
Answer So Far: NO
Rhexis Smoothness and Strength
Prior to Neuhann and Gimbel`s CCC anterior capsule capsular tears
8
occurred 100% of the time. The smooth edge of the CCC rhexis is very
resistant to tearing.
However making a CCC in pediatric cases is more difficult because the
capsules are more elastic than in adults and the rhexis tends to run off
to the periphery during manual CCC.
In the 90`s new devices were tried in order to facilitate the CCC. These
included vitrectors, diathermy and the Fugo “plasma blade”.
Researchers compared these techniques to CCC. It turned out that manual CCC
was the Gold Standard and none of the techniques were as good.37,38,39,40
They looked at 2 things:
1)smoothness of the edge: Phaco Much Smoother than all other techniques
Scanning electron micrographs (SEM’s) of the anterior capsular edge
Vitrectorhexis
CCC
Can Opener
CCC Obviously
the Smoothest
Radio-Frequency Diathermy
Plasma Blade
Smoothness and
Strength (Cont’d)
2) Resistance to capsular tearing
All studies showed that a CCC had a significant higher amount of stretch prior to
tearing as well as higher amount of force required to tear the rhexis edge. It was
assumed the rough edges with other techniques made it prone to tear the edge.
The studies used 2 pins usually on calipers (each pin about 1 mm in diameter) and they
opened the pins within the rhexis and measured how far the rhexis stretched prior to
tearing. Some of the pins were attached to a device that could measure the force
required to reach the tearing point.
38
Smoothness and Strength
How to Study It (Cont’d)
What We Learn From the Blue Dye Studies
Blue Dye is used in cases when the cataract is so advanced that visualization of the anterior
capsule during making of the manual CCC is difficult (poor red reflex). Staining the anterior
capsule is very helpful for visualization.
Several Studies have been done to see whether blue dye alters the capsule properties. It has
41,42,43,44
been shown to decrease elasticity and increase stiffness of the capsule.
To test whether blue dye reduces the rhexis` resistance to tearing Jaber, Werner, Mamalis at
Moran Eye Center at the University of Utah did a study (with help from a grant from Alcon).
Instead of narrow diameter pins stretching the rhexis they devised a testing device to more
closely “simulate forces and displacements that the CCC might withstand during
hydrodissection and nucleus cracking and chopping”. 45,46,47
They used two 4.4mm shoetree shaped fixtures totaling 8.8mm attached to a force
measuring device. There was no difference (with or without blue dye) in the force required
to tear the edge of the rhexis even though the rhexis is stiffer with blue dye.
The shoetree type of device used in this study may be relevant to how femto rhexis strength
has been studied today.
Femto Rhexis Edge Smoothness and Strength?
24
Nagy (JRS 2009) LenSx Pig Eyes: First in a major clinical journal that discussed the
promise of Femtolaser cataract surgery.
Smoothness:
SEM 300X magnification. Nagy states:
“the features of the laser capsulotomy
were AT LEAST AS SMOOTH as those
of the manual capsulorhexis”.
Note: only 300X was used (all the past
studies like this used 500 to 32,000X).
CCC edge
Strength:
Tested with Calipers: Femto stretched
213% and Phaco 198% (p<.001) in
favor of Femto.
Femto edge
29
Friedman (JCRS 2011) Catalys: Human Cadaver eyes
CCC edge
Femto edge
Smoothness: He writes that the femto edge is “smooth and continuous” and is
“sharpedged”. He refers to the obvious rough edge (relative to the smooth manual
CCC edge) as having “microgrooves”. No magnification was given.
Strength: Tested with pins attached to a force measuring device:
Femto = 113 to 152 millinewtons (mN)
Phaco= 65 mN
p<.05 in favor of Femto. .
48
Auffarth (JCRS 2013) Victus
Pigs Eyes
Smoothness:
No photos shown. Only says “in some eyes the SEM images of femto
looked much smoother.”
Strength:
Used pins. Femto=113mN and Phaco=73mN (p<.05)
Femto stretched 160% and Phaco 135%
(p<.05)
Femto vs. CCC
Manual CCC
Femto capsulotomy
The Femto Capsulotomy is beautiful looking but is it really stronger?
 Smoothness: All Company studies imply or say femto edge is at least as smooth
as CCC.
 Strength: No Femto strength test utilized the Shoetree test used at Moran Eye
Center which better simulates intraocular forces encountered during phaco.
 These Company studies came out early and taught doctors that the Femto Rhexis
was just as smooth and stronger than CCC. But other studies were soon to follow.
Ostovic (surgeon Kohnen) (2013)
49
Human Cases:
Phaco CCC and LenSx (with curved glass interface) SEM up to 10,000X
Femto
Damaged Region Along Edge
CCC
Undamaged Cells Along Edge
Femto
Tag
Femto
Femto
Femto
Sawtooth Pattern
Misplaced Pulses
Tag
Mastropasqua (JCRS 2013)
50
Human Cases; Lensar at 7mj energy, LenSx at 13.5, 14, 15mj:
1000X
A. Manual CCC; B-E. Femto with Increasing Laser Energy Settings
51
Abell (4 surgeons from 4 different centers)(Oph 2014)
Human Cases: 10 Phaco eyes and 40 Femto eyes (Catalys, LensAr and LenSx
with newest soft contact interface). SEM`s 20X to 30,000X.
Note: LenSx type of curved glass interface has been shown to cause wrinkles in
the cornea during creation of the rhexis; the wrinkles block the uptake of the
laser pulses leading to gaps of untreated /incomplete rhexis edges. This has been
improved with the soft contact interface (SoftFit) but not eliminated.
Each laser platform (not just LenSx) were found to have anterior capsulotomy
tags and also misplaced laser pulses (the latter consistent with eye
movement during treatment).
(Note pig and cadaver eye studies done in the earlier studies were able to be kept
perfectly still).
Able says “All 3 platforms were compromised by postage-stamp perforations
that appeared rough.”
Abell (Cont’d)
SEM 1500X
LenSx anterior capsular Tag
SEM 10,000X
Catalys irrigular edge;
arrows: misplaced laser
pulses
SEM 10,000X
Catalys micro-can
opener structure
SEM 1100X
LenSx jagged
edge
SEM only 300X
Catalys anterior capsular Tag
SEM 10,000x
Lensar irregular edge
SEM 10,000X
CCC smooth
SEM 1100X
Ccc smooth
SEM 1400X
Lensar higher mag. of jagged edge
Femto Complications:
Some are suction breaks, poor incisions, miosis, subconjunctival
hemorrhage, and misplaced corneal laser pulses.
But the most disturbing one and the one we will look closely at
is Anterior CapsularTears (A.C. Tears).
These can lead to posterior tears and vitreous loss and also as
Andreo/Apple showed in the `90`s it can cause a relatively large
decentration of the IOL.
Femto Complications (Cont’d)
Bali (Oph 2012) 52
LenSx (with curved interface)
Tag
Prospective study of the first 200 femto cases of
a 6 surgeon group compared the complications
to those with their previous (retrospective) 1000
regular phaco cases.
They state that these complications are part of
the “learning curve” associated with any new
procedure and that with experience the
complications can be overcome.
They suggest that since anterior capsular tags
were commonly present with femto that anterior
capsular tears resulted.
A.C. Tear
Bali (Cont’d)
First 100 femto`s then second 100 and also results of prior 1000 manual phaco.
“Exclusion criteria included glaucoma, pseudoexfoliaton, small pupils (<5.0 )
or previous corneal surgery.” Note: definition of free floating cap=”required no
manual detachment”.
Cases
Free
Floating
Rhexi
Tags
A.C.
Tears
(A.C.T.)
1-100
6 (6%)
14 (14%)
7 (7%)
101-200
29 (29%)
7 (7%)
1 (1%)
Total
35 (17.5%)
21 (10.5%) 8 (4%)
1000 PEM
A.C. Tear
extended to
P.C. Tear (P.C.T)
Other
P.C.T.
4 (50% of
A.C.T.’s)
3 (1.5%) 7 (3.5%)
8 (0.8%)
Total
P.C.T.’S
3 (0.3%)
A.C. Tear= anterior capsular tear; P.C. Tear= posterior capsular tear
Difference between A.C. Tears first 200 Femto (4%) and Phaco (.8%): p=<.001
But note the steep decline in A.C. Tears in the second 100 cases.
The Difference between Total Femto P.C. Tears (3.5%) and Phaco (.3%): p=<.001
Bali (cont’d)
They state: “the geometry of the capsular tags led to
extension and formation of capsular anterior capsular
tears.”
They recommend carefully looking for tags/notches and
then completing the incomplete rhexis manually very
carefully to avoid capsular tears.
They also stated that better docking of the eye to the
laser interface led to more free floating rhexi which
required no manipulation of the rhexis manually and
thus a decreased risk of capsular tear formation.
Note the trend with experience of more free floating rhexi
and fewer tags and less anterior capsular tears.
Roberts (Oph 2013)
53
This is a follow-up to the Bali article (LenSx still with curved interface). Same
group`s next 1300 femto cases after the first 200.
Note: They combine Free Floating Cap (FrFl in table) and “postage-stamp” (PS in
table) configuration which they later define as “small areas of non-perforation not
impacting on complete removal of the capsule button”.
Cases
Fr Fl and Tags
PS Rhexi
A.C.
Tears
A.C.T.
extending
to P.C.T.
Other
P.C.T.
Total
P.C.T.’s
Total
A.C.T.’s
& P.C.T.’s
1-200
17.5%
true free
floating
21
(10.5%)
8 (4%)
4 (50% of
A.C.T.’s)
3 (1.5%)
7 (3.5%)
7.5%
201-1300
96% Fr.
Fl. & P.S.
21 (1.6%)
4 (0.3%)
2 (50% of
rt’s)
2 (.15%)
4 (0.3%)
0.62%
1000
PEM’s
8 (.8%)
3 (.3%)
Femto cases 201-1300 had much fewer A.C. Tears and P.C. Tears than first 200 (p<.001)
and no different than their previous 1000Phaco cases.
Roberts (cont’d)
Roberts states:
“Friedman et al have shown that a laser-created capsulotomy may
be more than twice as strong as a capsulorhexis created manually,
suggesting that normal manipulation and stretching of the
capsulotomy during phacoemulsification would be unlikely to tear
the capsulotomy.” And “ A.C. Tears are more likely to result from a
microtag being stretched and torn during intracapsular
manipulation and we recommend inspecting the edge of the laser
cut capsulotomy for a capsular tag under higher magnification
before phacoemulsification.”
Roberts concludes: Better Results after the “learning curve” because:
Improved laser settings and patient positioning skills  fewer incomplete
capsulotomies and tags.
Better Capsulotomies and better intraocular surgical technique  fewer A.C.
Tears
54
Nagy ( JCRS 2014)
LenSx
First 100 Femto Cases (Learning Curve ) with early technology dating back to
2008 using curved interface.
Exclusion: miosis, zonular weakness, active ocular disease
Tags
capsular Tears
RT to PCT
20 (20%)
4 (4%)
0
Nagy spends a lot of time discussing technique of manual completion of the
capsulotomy depending on which of 4 possible femto rhexi present themselves.
“Greater surgeon experience and improved technology are associated with a
significant reduction in complications.”
54
Note: PUPIL SIZE: Nagy states that the Rhexis should be set to 1.5 mm less than the pupil or
else shockwaves from the laser will hit the papillary margin thereby causing miosis and
inflammation. We know that small rhexi can cause phimosis and hyperopic shifts- Cecik (Oph
1998)1 compared 4.0 to 6.0 rhexi and Sanders (JCRS 2006) 3 noted if rhexis <5.5mm there is an
increased chance of capsule fibrosis with posterior displacement of the IOL with hyperopic
shift. According to Nagy to have a 4.5mm rhexis a pupil must dilate to 6.0.
56
Abell (surgeons Vote and Davies)(Oph. 2014)
(Catalys)
A. C. Tear Rate of Experienced Femto Surgeons
2 Experienced Femto Surgeons at 2 Different Centers
Prospective study: Anterior Capsule Tear Rate
804 femto cases vs. 822 manual Phaco’s. Correlated with ultrastructural integrity
of the rhexis 
100% either free floating or with very delicate connections
A.C. Tears:
Phaco Better (p<.002)
Femto
→ 15 Anterior Capsular Tears (1.87%)
Phaco
→ 1 Anterior Capsular Tear (0.12%) p<.0002
→ 7 with Capsular Tear extending to Posterior Capsule (47%)
15X Better
There was no significant difference between the 2 surgeons` results
Prior anterior tear rate at the 2 centers = .06% and 0.2% which corresponds with
the .12% rate in this study.
Abell (cont’d)
Unlike Bali and Roberts, Abell states: No A.C. Tears were noted while removing the capsule.
“Most occurred during hydrodissection or during lens manipulations”. Only one occurred prior
to hydrodissection. He states, None seemed to occur because of tags or focal attachments.
Looking carefully with high magnification and a careful capsule removal technique would not
have helped in these cases.
They say their SEM`s showed a Femto capsulotomy creates a microscopic can-opener rhexis
edge with both the LenSx, Lensar and Catalys lasers. It has “tags, skip lesions as well as regular
lines of aberrant misfired pits presumably from…eye movements”. “..no difference in images
from before and after the latest software and hardware upgrades including the LenSx SoftFit PI
for each of the laser platforms”.
 Contrary to Bali, Roberts and Nagi’s recommendations,
Abell states that looking carefully with high magnification
and a careful capsule removal technique would not have
helped in any of these cases.
Equally poor capsular edge with all three lasers, and no
difference in edge quality from before and after the latest
software and hardware upgrades including LenSx SoftFit.
57
Chang (JCRS 2014)
Lensar; Complications of first 170 Femto eyes of 3 surgeons and 180 Phaco eyes
during same time period.
Lensar has fluid filled interface similar to Catalys. Should have more complete
rhexi than LenSx.
Femto (170)
Free
Floating
Fr. Fl. &
mild
adhesions
Tags
A.C.T.’s
P.C.T.
88.8%
100%
2.4%
9 (5.3%)
1 (0.56%)
3 (1.7%)
N/A
Phaco (180)
 No financial ties to Lensar but works with AMO, Alcon, and Technolas)
Chang (Cont’d)
No A.C.Tears occurred during capsule removal; all after
hydrodissection and during the subsequent surgical maneuvers
and prior to IOL insertion. None of the 2.4% of eyes that had
tags had anterior capsule tears.
He Concludes:
The postage stamp effect of the microgrooves had micronotches
making it easier to tear radially. He says “We suspect femto
laser capsulotomy is weaker than manual CCC.”
Thus similar to Abell and unlike the views of Bali,Roberts, and
Nagi none of the A. C. Tears happened because of a higher
incidence of incomplete flaps or inexperience at removing or
completing the rhexis.
Addendum for A.C. Tears and Tags
(Small Non-comparative Studies)
58
Conrad-Hengerer (surgeon: Dick) (JRS 2012)
A study comparing EPT with femto and standard phaco.
 57 Femto eyes. (Note: pupils  6.0)
Free Floating anterior capsule=100%
“Tags”= 0%
“small tongue-like capsular processes”= 3 (5.3%)
A.C. Tears= 0%
59
Conrad-Hengerer (surgeon :Dick) (JCRS 11/2012)
Catalys: A study comparing femto grid sizes and EPT.
 160 Eyes; pupils  6.0.
Free floating anterior capsule=100%
“Tags”= 0%
A.C. Tears= 0%
60
Abell (surgeon: Vote) (Oph 5/13)
Catalys: A Study comparing femto and phaco EPT and corneal edema.
150 femto eyes
Tags= 0%
Tears= 0%
61
Mayer (surgeon: Kohnen) (AJO 2/14)
LenSx (with Soft Contact Lens Pl, aka “SoftFit”)
88 femto eyes
Tags= 0%
Tears=0%
Phaco Power, Endothelial Cell Loss and
Corneal Edema
Femto vs. Phaco
Effective Phaco Time (EPT)= the multiple of total phaco time and
average % power used, which represents a metric for the length of
phaco time if it has been used at 100% power in continuous mode.
62
Nagy (JRS 2009)
(LenSx) Adult Pig Eyes:
Lenses pre-treated with Femto vs. standard divide and conquer
phaco:
→ 51% Reduction of EPT with femto.
63
Takacs (surgeon, Nagy) (JRS 2012)
LenSx: 38 femto cases and 38 phaco (div & conq)
Central corneal thickness:
Femto significantly better (p<.05) only at Day 1 (femto= 580 ± 42 and phaco=
607 ± 91.
There was no significant difference at 1 week or 1 month.
Central Endothelial Cell Count:
No statistically significant difference between Femto and phaco.
Volume stress Index (VSI): indicates corneal endothelial cell function; based on a
measurement of post-op alteration of central corneal volume and central endothelial cell
density)
Femto significantly better at day one but not 1 week or 1 month.
Question: if they are measuring corneal edema why do they not document CDVA? It is
certainly easier data to present than VSI. Was there no difference even at day 1?
58
Conrad-Hengerer (surgeon: Dick)(JRS 2012)
(Catalys) 57 phaco cases vs. 52 standard phaco cases (stop and chop) for
cataract grades 2, 3, 4. Measured Effective Phaco Time (EPT)
Figure 2. Diagrams showing (A) 500-m softening grid pattern
compared
with (B) 400/200-m segmentation and softening grid pattern.
Femto EPT= 0.16 ± 1.21 sec.
Phaco EPT = 4.07±3.14 sec.
Femto → 96% reduction of EPT
Researchers still working out best ways to
soften and segment the nucleus.
60
60
Abell (surgeon: Vote)(Oph 2013)
(Catalys) 150 femto and 51 phaco eyes (div & conq)
EPT :
Femto= 2.33 ± 2.28
Phaco=14.24 ± 10.90
Femto → 84% reduction of EPT (p<.0001)
30% Femto used 0 EPT; no Phaco eyes used 0 EPT; lowest Phaco EPT=
4.9 sec.
Endoth Cell Loss 3 weeks post-op:
Femto = -143.8+/-208.3 Femto better with p=0.022
Phaco= -224.9+/- 188.95
Central Corneal Thickness Increase on Day 1= No significant difference
(Note: No One Day Post-Op CDVA’s given.)
Conrad-Hengerer (surgeon:Dick) (JCRS 2013)
65
(Catalys)
Prospective, Intraindivual , ie. Bilateral Eye Study
One eye Femto, other eye Phaco (stop and chop)
73 eyes each ; Note pupils had to be  6.0mm
Cataract Grade
Mean EPT Femto Mean EPT Phaco
2
0
0.32 ± .22
3
0.02 ± 0.03
1.17 ± 0.69
4
0.09 ± 0.15
2.5 ± 1.07
64.4% Femto used 0 EPT. No phaco eyes used 0 EPt; lowest phaco EPT=0.07
Endothelial Cell Loss: Femto somewhat better; no P values given. It does state “the
change in less loss between the 2 groups was statistically significantly different over
the whole post-operative period (p<.001).
Conrad-Hengerer (cont`d)
Central Corneal Thickness
Exam
Femto Mean
Phaco Mean
Pre-op
553
553
1 day post-op
626
639
3-4 days
594
605
1 week
580
582
6 weeks
552
553
3 months
551
553
OBVIOUSLY no significant difference at any time, yet the Discussion states: “There was a
significant reduction in central corneal thickness after femto.” If they are referring to
post-op day #1, then that certainly isn’t by much.
CDVA: CDVA was obtained at one day, 3-4 days, 1 wk and 3 months. No Visual Acuity
results or difference in results were given. It only states that CDVA (assume for both
femto and phaco) correlated with EPT at 1 day and 1 wk. However in the Discussion
section it states “the visual results 1 day after surgery were significantly better” in the
femto group.
Note: Perhaps the authors of this study can clarify the gaps in the data/statistics
reported. I do not see p values for difference in endothelial cells loss and I do not see
visual acuities documented.
Mayer (surgeon: Kohnen)
61
LenSx. Effective Phaco Time (EPT) and Endothelial Cell Loss (ECL); 88 eyes
Femto vs. 62 eyes Phaco. Measured Endothelial Cell Count (ECC) pre-op and 1
month post-op.
EPT:
Femto=1.58+/-1.02
Phaco= 4.17+/-2.06
ECL:
Significantly Less ECL with Femto at 1 month (p=.02)
Femto better (p<.001) and better for
all nuclear grades (p<.01)
Summary of Literature Results for Femto Providing
Better EPT, ECL, and CCT
EPT= Effective Phaco Power
ECL= Endothelial Cell Loss
CCT= Central Corneal Thickness
N/A= not available
EPT % ECL Less
Lower
CCT Thinner
Nagy (‘09)
51%
N/A
N/A
Takacs (‘12)
N/A
No
p<.05 day 1 only
Hengerer
(‘12)
96%
N/A
N/A
Abell (‘13)
84%
Yes (p=.02)
No
Mayer (‘14)
62%
Yes (p=.02)
N/A
 Studies agree EPT is lower with Femto
 ECL is somewhat less with Phaco
 CCT may or may not be slightly less on post-op day #1
with Femto
POST-OP INFLAMMATION & MACULAR EDEMA
Ecsedy (surgeon: Nagy) (JRS 2011)
66
LenSx: 20 femto and 20 phaco eyes (divide & conquer). No NSAIDS given.
OCT 1 Week and 1 Month
OCT
Fovea= central .5mm radius
Inner ring= 1.5mm radius
Outer ring= 3.0mm radius
Results:
Change in Macular Thickness: No Results Given.
They did give results for Change in Macular Thickness
when adjusted for Age.
Post-op Inflammation and Macular Edema (Cont’d)
Ecesdy (Cont’d)
Femto vs. Phaco Change in Macular Thickness (Adjusted for Age)
MACULAR AREA
1 WEEK
1 MONTH
Total Macula
p>.05
p>.05
Fovea
p>.05
p>.05
Inner Ring
p<.001
p>.05
Outer Ring
p>.05
p>.05
MEAN POST-OP CDVA (in LogMAR converted to Snellen by me)
Femto
Phaco
1 week
.16 (20/28) ±.27
.08 (20/23) ± .16 (p>.05)
1 month
.08 (20/23) ± .19
.02 (20/21) ± .06 (p>.05)
Note: CDVA with Phaco somewhat Better but p>.05
Nagy
67
LenSx: 12 Femto and 13 Phaco eyes. No NSAIDS. Macular OCT at 4-8 wk post-op
(peak macular edema period).
Note: No Pre-op Macular Thickness Obtained so No Post-op Change in Macular
Thickness Given. Only Post-op Absolute Macular Thickness Reported.
OCT measured not only thickness of total macula, fovea, inner and outer rings but
also each retinal layer within each region.
OCT Results:
NO SIGNIFICANT DIFFERENCE (p>.05) for ALL LAYERS OF Total Macula, Fovea, Inner
and Outer Rings
EXCEPT: Femto mildly better for:
1) Outer Nuclear Layer (rods and cones) of
Inner Ring (p=.04)
2)Outer Nuclear Layer (rods and cones) of
Outer Ring (p=.04)
CDVA RESULTS (Snellen in decimals):
Femto: 1.0 ± 0 (20/22)
Phaco: .95 ± .08 (20/22)
(p>.05)
Abell 68
100 Femto Eyes vs. 76 Phaco Eyes. Post-op NSAIDS given.
Measured:
Aqueous Flare 1 day and 1 month post-op
Macular OCT pre-op and 1 month post-op (fovea, inner and outer rings)
Results:
EPT: Femto less (p<.0001)
Aqueous Flare:
1 week Femto Clearer (p=.009)
1 month Femto Clearer (p=.003)
Slit Lamp Exam: no difference between Femto and Phaco in anterior chamber appearance.
CHANGE IN MACULAR THICKNESS (1 MONTH POST-OP) FEMTO VS. PHACO
Fovea
No Significant Difference
Inner Ring
No Significant Difference
Outer Ring
Femto better: p=.007
Fundus Exam no difference between Femto and Phaco.
SUMMARY OF LITERATURE: FEMTO vs. PHACO
INFLAMMATION AND MACULAR EDEMA
Flare
Total
Macula
Fovea
Inner Ring
Outer Ring CDVA
Ecsedy N/A
No Diff.
No. Diff.
Femto
Better
p<.001
No Diff.
No Diff.
Nagy
N/A
No Diff.
No Diff
Femto
Better
ONL
p=.04
Femto
Better
ONL
p=.04
No Diff.
Abell
Femto Better
No Diff.
1 week p=.009
1 mo. P=.003
No Diff.
No Diff.
Femto
Better
p=.007
N/A
 One study has been done and showed Flare is less with Femto
 No Difference in Total Macular or Foveal Edema
 Somewhat Less Edema in the Inner and Outer Macular Rings
 Macular Edema Studies showed No Difference in CDVA
So What Does the Current Literature Teach Us to Date?
Does Femto create a prettier looking rhexis that leads to better IOL overlap?
Answer: Yes.
Does a prettier Femto rhexis with better overlap provide a better refractive outcome?
Answer: No.
Does a prettier Femto rhexis with better overlap provide better quality of vision with spherical, aspheric, neutral
aspheric, or multifocal IOL’s?
Answer: No.
Is the Femto Rhexis edge smoother or rougher than a CCC?
Answer: Rougher.
Is a Femto Rhexis weaker or stronger than a CCC?
Answer: Probably weaker.
Is there a significant Learning Curve to Femto?
Answer: Yes.
Does Femto become as safe as Phaco after the Learning Curve?
Answer: There is a real danger that it will not in many surgeons` hands.
Does Femto minimize endothelial damage?
Answer: Probably somewhat.
Does Femto decrease postop corneal edema?
Answer: possibly slightly on postop day 1 only
Does Femto minimize macular edema?
Answer: probably but not in the fovea and only in the inner and outer macular rings
Is Femto superiority to Phaco an inevitability or is the basic platform flawed?
Answer: The mantra is that it is improving and some day…….But perhaps the basic platform is
flawed and not only is the benefit not worth the cost but also there may be NO way to improve the
jagged rhexis edge despite lowering the energy settings.
Is Femto a Revolution, Evolution or No Solution?
Answer: you be the judge.
Citations
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30.
31.
Cekic; Oph. Surg. And Lasers; 1998; 30; p185Norby; JCRS; 2008; 34; p368Sanders; JCRS; 2006; 32; p2110Friedman; JCRS; 2011; 37; p1193Kranitz; JRS; 2011; 27; p560Neuhann; Aug. 1987; 190; p542Gimbel; JCRS; 1990; 2; p63Assia; Arch Oph; 1991; p109Assia; Oph; 1993; 100; p153Eppig; JCRS; 2009; 35; p1091Okada; Oph; 2014; 121; p763Kasper; JCRS; 2006; 32; p2023Wang; JCRS; 2003; 29; p1514Holladay; JRS; 2002; 18; p683Piers; JRS; 2007; 23; p374Piers; JRS; 2007; 23; p380Kasper; JCRS; 2006; 32; p78Kasper; JCRS; 2006; 32; p2022Baumeister; JCRS; 2009; 35; p1006Applegate; JCRS; 2003; 39; p1487Eppig; JCRS; 2009; 35; p1097Eppig; JCRS; 2009; 35; p1098Johansson; JCRS; 2007; 33; p1565Nagy; JRS; 2009; 25; p1053Tackman; JCRS; 2011; 37; p829Palanker; Sci. Trans. Med.; 2010; 2; p1Nagy 2011; JRS; 27; p564Kranitz; JRS; 2011; 27; p558Friedman; JCRS; 2011; 37; p1189Reddy; JCRS; 2013 39; p1297Kranitz; JRS; 2011; 27; p558-
32. Milhaltz; JRS; 2001; 110; p71162. Nagy; JRS; 2009; 12; p105333. Kranitz; JRS; 2012; 28; p25963. Takacs; JRS; 2012; 6; p38734. Filkorn; JRS; 2012: 28; p54064. Conrad-Hengerer; JCRS; 2012; 38; p189035. Lawless; JRS; 2012; 28; p85965. Conrad-Hengerer; JCRS; 2013; 9; p130736. Abell; Oph; 2013; 5; p94266. Ecsedy; JRS; 2011; 27; p71737. Krag S, JCRS; 1997; 23; p8667. Nagy; JCRS; 2012; 38; p94138. Andreo; JCRS; 1999; 25; p53468. Abell; JCRS; 2013; 39; p132139. Izak A; JCRS; 2004; 30; p260640. Trivedi; JCRS; 2006; 32; p120641. Wollensak; JCRS; 2004; 30; p152642. Dick B; JCRS; 2008; 34; p136743. Jardeleza; JCRS; 2009; 35; p31844. Haritoglou; JCRS; 2013; 39; p174945. Werner; JCRS; 2010; 36; p50746. Jaber; JCRS; 2012; 38; p195447. Jaber; JCRS; 2012; 38; p50748. Auffarth; JCRS; 2013; 39; p10549. Ostovic; JCRS; 2013; 39; p158750. Mastropasqua; JCRS; 2013; 39; p158151. Abell; Oph; 2014; 121; p1752. Bali; Oph; 2012; 119; p89153. Roberts; Oph; 2013; 120; p22954. Nagy; JCRS; 2014; 40; p2055. Nagy; JCRS; 2014; 40; p2456. Abell; Oph; 2014; 121; p1757. Chang; JCRS; 2014; 40; p2958. Conrad-Hengerer; JRS; 2012 ; 2; p87959. Conrad-Hengerer; JCRS; 2012; 38; p188860. Abell; Oph; 2013; 5; p94261. Mayer; AJO; 2014; 2; p426-