devgan. phaco fundamentals. book
TRANSCRIPT
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Supported by an unrestricted
educational grant from Bausch & Lomb
CME SERIES
phacofundamentalsFor The Beginning Phaco Surgeon
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Phaco Fundamentals 1.0An exploration of the basics of safe,
technically advanced cataract extraction
lesson Plans08
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Uday Devgan, MD, FACS
Uda Deva, MD, FACS is a caaac ad efacive sueo a he Maloe Visio Isi ue, he
pemie pivae ophhalmic pacice i Los Aeles, Califoia. He pefoms he full specum
of coeal ad leicula efacive ad esoaive sue ad has isuced housads of
sueos i 30 couies. D Deva is Chief of Ophhalmolo a Olive Vie UCLA Medical
Cee ad Associae Cliical Pofesso a he Jules Sei Ee Isiue a he UCLA School of
Medicie i Los Aeles, hee he is he ol facul meme o have eaed he pesiious eachi a ad
ice. D Deva ies mohl colums i muliple ophhalmic jouals oldide ad is a cosula fo
ma majo ophhalmic compaies. He ca e eached a .UdaDeva.com fo fuhe ifomaio.
1. The Basic Phaco Machine
2. Concepts of Fluidics
3. Flo Balance & Tubin Compliance
4. Optimiin Phaco Fluidic Settins
5. Fundamentals of Ultrasonic Phaco Poer
6. Continuous, Pulse, And Burst Phaco Modes
7. Hper Settins
8. Variable Dut Ccle
9. Variable Rise Time And Custom Settins
10. Creatin A Clear-Corneal Cataract Incision
11. Hand Position & Pivotin
12. Bevel Position; Incision Spacin
13. Foot Pedal Control Durin Steps Of Surer
14. Viscoelastics: Dispersive & Cohesive
15. Capsulorhexis Creation
16. Hdrodissection and Hdrodelineation
17. Concepts Of Nucleus Removal
18. Divide-and-Conquer Technique of Nucleus Removal
19. Stop-and-Chop Technique of Nucleus Removal
20. Quick Chop Techniques of Nucleus Removal
21. Cortex Removal
22. IOL Insertion
23. Incision Closure & Dressins
24. Post-op Medications & Follo-up
The causes of cataract are complex and
obscure, ranging from the unrelenting
forces of genetics and aging to the fate-
ful impacts of environment, climate,
diet, disease and trauma. Yet its effect
is simple: the progressive cloud-
ing of the eyes crystalline lens to
the point of opaqueness, robbing
the patient of sight. Medicines ef-
forts to slow or halt this progression
have failed. Yetas was obvious
even to the ancient Indian surgeon
Sushrutathe answer to cataract
lies in removing the obstruction to
restore the passage of light onto the
macula. The history of cataract sur-
gery has been an unremitting quest
to remove the obstaclethe no-
longer-crystalline lens. Sushrutas
genius was simply to nudge the ob-
struction aside, a procedure called
couching that persisted well into modern times. The
machine age saw attempts to extricate the lens via
incision, but it wasnt until the second half of the
20th century that surgeons, empowered by micros-
copy and precision implements, nally succeeded at
cataract extraction.
Intracapsular cataract extraction involved removal
of the lens and capsular bag as one, with the refrac-
tive power of the now-absent lens provided exter-
nally by massive Coke bottle spectacles. Its hard
to believe today that ICCE was the state of the art
as recently as 1980. Sir Harold Ridleys observation
that World War II aviators could tolerate shards of
aircraft canopy glass in their eyes prompted him to
use that materialactually polymethylmethacrylate,
or PMMAto fashion the rst intraocular lenses.
Ridleys innovation inspired surgeons to r emove the
opaque lens while leaving intact the
capsular bag as a receptacle to hold
his IOLs, and extracapsular cata-
ract extraction was born. ECCEs
breakthrough was the capsulotomy,
removal of the anterior capsule to
allow wholesale delivery of the
nucleus, to be replaced by a PMMA
lens with known refractive quali-
ties. Its a nifty trick that remains
in many eye surgeons repertoires,
and a staple of most residency train-
ing programs. Renement of ECCE
technique led to extraction via
smaller incisions that afforded sta-
ble intraocular pressure during sur-
gery and sealed without sutures, a variation called
manual small-incision cataract surgery. With SICS
and low-cost IOLs, cataract surgery now penetrates
even the worlds poorest communities and surgical
volumes have risen into the millions.
Yet the sheer mass of the cataractous lens posed a
physical barrier to smaller, less-traumatic incisions.
Charles Kelman toppled this barrier with his idea of
emulsifying the nucleus inside the eye for removal
via aspiration, a task accomplished with targeted
ultrasound and dubbed phacoemulsication. Inci-
sions have been shrinking ever since, with advances
the machine age saw
attemPts to extricate
the lens via incision,
but it wasnt until
the second halF oF
the 20th century that
surgeons, emPowered
by microscoPy and
Precision imPlements,
Finally succeeded at
cataract extraction.
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WoRld RepoRt cme seRIes phaco fundamentals
in computer control and engineering and successive
generations of foldable IOLs allowing surgeons
to all but replicate the human lens with minimal
trauma to the eye. The incision-size benchmark for
commercially available systems now has dropped
below 2mm, as with Bausch & Lombs 1.8mm Stel-
laris platform and its Akreos MI60 foldable
intraocular lens.
While phacoemulsication has become the prevail-
ing standard in the industrialized world, where cata-
ract usually is treated in its early stages before the
patients vision is dramatically impaired, this is not
the case in much of the world. In India and China,one can still encounter almost the entire history of
cataract surgerya relatively even mix of ECCE,
SICS and phaco punctuated by isolated pockets of
ICCE and, by some experts telling, even linger-
ing instances of couching. See gure 1. The good
news is that advanced surgical skills are spreading in
both countries. Surgeons are moving rapidly toward
phacoemulsication as more and more patients, in-
creasingly aware of the benets of early interven-
tion, are expecting their ophthalmologists to use the
latest technologies.
But what exactly is phacoemulsication? While its
easy to conceptualize, its actually one of the most
complex forms of microsurgeryinvolving simul-
taneous machine-controlled irrigation and aspiration
to maintain anterior chamber stability, even while
the ultrasound tip manipulates and blasts away at
the nucleus. Theres a lot that can go wrong, and top
surgeons say the best defense against complications
is to know the technology as well as the procedure.
The purpose of this book, a compilation of the 24-
part Phaco Fundamentals series that was rst syndi-
cated in Ophthalmology World Report, is to establish
a foundation of knowledge about all aspects of the
phacoemulsication system, its processes and its op-
erations. The author, Dr. Uday Devgan, is a renowned
U.S. surgeon in private practice at the Maloney Vi-
sion Institute in Los Angeles and associate clinical
professor of ophthalmology at the Jules Stein Eye
Institute in the School of Medicine of the University
of California, Los Angeles. Dr. Devgan has dedicat-
ed a large part of his teaching to understanding and
explaining the fundamentals of phaco in ways that
demystify the technology, and empower surgeons to
use it safely and to maximum advantage.
The Phaco Fundamentals series has given our World
Report editorial team a unique glimpse into the state
of cataract surgery in both India, where our circu-
lation exceeds 10,000 ophthalmologists, and China
where we have 17,000 registered readers. This com-
piled edition was requested by more than 3,000 doc-
tors in China and 1,100 in India, and each provided
a snapshot of their current practice. The compiled
data, comprising one of the largest surveys of cata-
ract ever undertaken in either country, revealed a
wide range of surgical skills and experienceand
a strong hunger for knowledge and surgical oppor-
tunity. In India, only about 14% of re spondents de-
scribed their phaco skills as advanced, while 80%
placed themselves in the basic or intermediate cat-
egory. See gure 2. In both countries, doctors over-
whelmingly cited the cost of equipment as the main
barrier to their own adoption of phaco. Nonetheless,
the survey showed that Indian and Chinese ophthal-
mologists hold phaco in high regard, saying it was
attractive for clinical reasonsanterior chamber
stability, low rates of induced astigmatism, lower
rates of infection and other complicationsas well
as practical ones such as patient comfort, reliability
and competitive market advantage. The study cap-
tured data about more than 2,000 phaco machines,
showing that large numbers are 4-5 years old and
likely to be replaced soon. See gure 3. Respon-
dents said their No.1 requirement in a replacement
system was affordability, followed by user friendli-
ness and ability to maintain a stable anterior cham-
ber during surgery.
About 70% of the 4,100-plus respondents said Phaco
Fundamentals was pitched to a comfortable level of
difculty, but they also presented a long list of ideas
for further studysuggestions that editors are using
to design the next cycle, which we are calling Pha-
co Fundamentals 2.0. Were preparing chapters on
many aspects of phaco practice, including the learn-
ing curve when transitioning to phaco from ECCE or
SICS, the different types of phaco systems, various
IOL types and applications, typical complications
and their management and pearls of best practice.
The editors of Ophthalmology World Report wish to
thank Dr. Uday Devgan for his brilliant insights and
clear explanations. And we thank Bausch & Lomb
for the unrestricted educational grant that made
Phaco Fundamentals possible. Finally, we wish to
thank the thousands of World Report readers who
requested the compilation and provided their views
and suggestions.
Jeffrey Parker
Editorial Director
Ophthalmology World Report
PHACO SICS ECCE Other
35%
12%13%
45%55%31%
9%
5%
42%
50%
3%
WHAT IS YOUR PREFERRED
CATARACT TECHNIQUE?Sample size: 1107
1-3 Yrs 4-6 Yrs 7-9 Yrs 10 Yrs& above
HOW OLD IS
YOUR PHACO MACHINE?Sample size: 779
Basic Intermediate Advadced
EVALUATE
YOUR PHACO SKILLSSample size: 1060
F 1 F 2 F 3
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WoRld RepoRt cme seRIes phaco fundamentals
M
y hoSpItAL focuSES a-
ara, s Im arilarl exie
ab reeii e slia-
e eii pa fameals. I reall
areiae e aara-relae e r
maazie. yr sr eirial s rai-
ali is reall ell r me i m wr. I e
see mre ariles ab e maaeme
post-cataract complications and difcult cases
as well as e erseies a exeriees
exers rm er sials, wi a irm
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IAM A REguLAR REAdER Wrl
Report and nd it very informative
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a e se r eelme is as. pa
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d hp, y, J P
ophthALMoLogy Wrl Rer
as eare e amirai ma
reaers r is exelle rers,
see issemiai wlee a qal-
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oalml times, oalml Wrl
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blises e laes irmai ab srial
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isi i aal a erais.
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lal reaer. Ie se 20 ears a e
rassrs, ieeri a srer
for cataract, and nd the magazine to be very
ell. I sae eer isse Wrl Rer as a
reeree, b m se is imlee s I reall
e reeie e llee isse pa
fameals....
l J,
m c c hp, bj
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part to come out with a very simplied
e mreesie series a
ameals, wi is er sel r resies
lie me
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ophthALMoLogy Wrl Rer
arries a l aara erae
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series is reall . I lie see s se-
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ire raiiers wr a areer e-
elme. yr reri b srer a
eraies is s sel a I a i irel
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IAM vERy Much imresse b dr.
ua deas pa fame-
als series. I wis ae e ll se-
ries i e llee rm. I wis a
a Bas & Lmb r eri e ble
eri all 24 lesss a are
s. m,
m, t n
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phthALMoLogy Wrl Rer
as beme a imra wi-
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I is exremel ell. M earme is l
now embracing phacoemulsication. For a rel-
aiel iexeriee r lie me, Im ee
bai a elemear wlee a
r r maazie a e a r-
ie ai/isal iss a er raii ma-
erials. te sa as!
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pa fameals I e r
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which I have proted deeply.
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WoRld RepoRt cme seRIes phaco fundamentals
The BasicPhaco MachineALL PHACO PLAtFOrMS SHArE tHE SAME bASIC StrUCtUrE AnD COnCEPtS. tHEPHACO MACHInE AIMS tO bALAnCE FLUIDICS wItHIn tHE EyE, wHILE DELIVErIngULtrASOnIC EnErgy AnD VACUUM In OrDEr tO EMULSIFy AnD ASPIrAtE tHECAtArACt tHrOUgH A SMALL InCISIOn.
ally works by depressing it towards the oor with the
dominant foot (the right foot for most surgeons). Each
foot pedal position is additive to the previous positions,
so that while the pedal is in position 2 (vacuum/aspira-
tion) it is also providing the full function of position 1
(irrigation). Similarly, once the pedal is in foot position
3 (ultrasound energy), it is also providing the function
of position 2 (vacuum/aspiration), as well as position 1
(irrigation). [ F 1 p f. ]
FOOT POSITION 1: IRRIgATION
Its important to realize that during phacoemulsica-
tion, we are working in the very small space of the
anterior and posterior chambers, compromising well
under 1 cubic centimeter of space together. During
the surgery we must always maintain the stability and
structure within the eye, particularly to prevent col-
lapse of the anterior and posterior chambers which can
lead to severe c omplications.
The irrigation function of the phaco machine is meant
to provide a source of uid infusion into the eye during
the surgery. By depressing the foot pedal to position 1,
the infusion is turned on. There is no linear control of the
infusionthe infusion is either turned on or turned off.
The height of the infusion bottle determines the rela-
tive infusion pressure and ow rate during the sur-
gery. To keep the eye inated during surgery, we need
to ensure that the uid inow rate is greater than the
uid outow rate.
[ Figure 2: Irrigation of uid into the eye is the function of phaco foot
p 1. ]
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FOOT POSITION 2:
VACUUM / ASPIRATION OF FLUID
Phaco foot position 2 is the control of the relative aspira-
tion and vacuum level of the uid from the eye. There
is a linear control of vacuum and ow, so that the top
of foot position 2 provides less vacuum or ow than the
middle or bottom range of the same foot position 2. This
is similar to the gas pedal in a car, where the cars throttle
is opened more as the gas pedal is further depressed. To
create the vacuum and the aspiration ow of uid, the
phaco machine must have a uid pump. The most com-
mon types of uid pumps are peristaltic and venturi,
and these will be explained fully in future columns.
The vacuum and aspiration levels that are created draw
the uid out of the eye and into a waste uid collec-
tion via the outow tubing. The regulation of vacuum
and aspiration is controlled by the foot pedal, with more
depression of the pedal resulting in higher levels. There
are two primary sources of uid outow during phaco-
emulsication: the outow from the phaco probe cre-
ated by the uid pump, and the leakage of uid from the
incisions. [ Figure 3: Vacuum and aspiration of uid from the eye is
f f p f p 1. ]
FOOT POSITION 3: ULTRASOUND ENERgy
The bottom-most position of the foot pedal is position
3, which controls the delivery of ultrasound energy into
the cataract. There is linear control of the ultrasound
energy level so that further pedal depression results in
more ultrasound energy, such as would be needed for a
denser cataract. Note that if the pedal is in position 3,
we are already engaging the full function of both posi-
tions 1 and 2. The irrigation is on, and the vacuum and
aspiration level is at its highest preset level. Ultrasound
energy should only be applied once the tip of the phaco
probe is in contact with part of the cataract.
When we look at the phaco probe closely, we see that
there are three lines attached: (1) the infusion tubing
carrying uid into the eye, (2) the outow tubing that
removes the uid via ow that is created by the phaco
machines uid pump, and (3) the line that carries the
electrical signals to control the ultrasound energy at the
tip of the phaco probe. These three lines correspond to
the three phaco foot pedal positions.
[ F 4: F p p 3 f
. ]
The three main functions of the phaco machine
are: (1) to provide irrigation into the eye, (2) to
create vacuum/aspiration to remove the cataract,
and (3) to deliver ultrasound energy in order to emulsi-
fy the nucleus. These three functions correspond to the
three phaco foot-pedal positions. The phaco foot pedal
is the primary instrument used to c ontrol the phaco ma-
chine during cataract surgery. This foot pedal tradition-
F 1
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0 WoRld RepoRt cme seRIes phaco fundamentals
Concepts of FluidicsDUE tO tHE SMALL VOLUME OF tHE AntErIOr AnD POStErIOr CHAMbErS, tHECOntrOL OF FLUIDICS DUrIng PHACOEMULSIFICAtIOn SUrgEry IS IMPOrtAnt tOEnSUrE EFFICIEnt rEMOVAL OF tHE CAtArACt wHILE PrEVEntIng COMPLICA-tIOnS DUE tO tISSUE COLLAPSE.
phaco uidics is to keep the inow greater than the out-ow. [ Figure 1: Keep inow greater than outow to ensure stability
f . ]
MODULATINg PHACO FLUID FLOw:
POISEUILLES EQUATION
The basic equation that governs all uid ow during
phacoemulsication surgery is Poiseuilles Equation:
F = P r / L
In this equation, F = ow, P = pressure gradient, r =
radius of the tube, = viscosity of uid, and L = length
of the tube. We are concerned with the relative relation-
ship and not the exact values, therefore, for simplicity
we can simplify this formula. The viscosity of the uid
is relatively constant, as is the length of the tubing. And
the values of pi and 8 are constant. This leaves us with
a simpler equation: F ~ P r
Flow is proportional to the change in pressure times the
radius of the tubing to the fourth power. Because the
value for tubing size is exponential, a small change to
the radius results in a large change in the relative ow.
This is clearly illustrated in a common sense situation
of drinking with straws. [ F 2: P eq
(a) q
lower ow, as compared to larger bore tubing (B) which can achieve a
high ow with less vacuum required. The change in ow is exponen-
f . ]
MODULATINg FLUID INFLOw
The source of uid inow is the bottle of balanced salt
solution that is hanging on the phaco machine. The
two factors that determine the rate of inow are: the
change in pressure and the radius of the inow tubing.
The change in pressure, can be modulated by raising
or lowering the height of the bottle relative to the pa-
tients eye: the higher the bottle, the higher the infusion
pressure. The inow tubing has a large radius in order
to maximize the ow and make sure that we keep our
inow greater than the outow. Similarly, the size of
the infusion channel within the phaco probe (or other
infusion instrument) is kept as large as possible so as to
not cause a bottleneck effect. [ Figure 3: Fluid inow can be
f p
gradient, as well as changing the radius of the inow tubing. ]
MODULATINg FLUID OUTFLOw
For uid outow, there are two sources of uid leav-
ing the eye: (1) the uid that is removed via the phaco
probe as a result of the vacuum level generated by the
uid pump, and (2) uid leakage from the incisions.
The rate of the uid outow via the phaco needle is
determined by the radius of the needle and tubing, as
well as the change in pressure generated by the phaco
machines uid pump. The rate of the uid outow loss
via the incisions depends on their size and the relativet of the instruments within these incisions.
Some degree of uid leakage from the incisions is help-
ful to allow cooling of the phaco needle and to prevent
thermal injury during surgery, particularly in early in
the learning stages of phacoemulsication. With the
use of advanced phaco power modulations, more ex-
perienced phaco surgeons tend to move towards tighter
incisions which can give more stable uidics.
The composition, nature, and size of the inow and
outow tubing are different.
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WoRld RepoRt cme seRIes phaco fundamentals
Optimizin PhacoFluidic SettinstHE CHALLEngE OF CAtArACt SUrgEry ArISES In LArgE PArt FrOM tHE SMALLCOnFInES OF tHE wOrkIng SPACE. tHE AntErIOr AnD POStErIOr CHAMbErCOMbInED tyPICALLy COMPrISE LESS tHAn 1 CUbIC CEntIMEtEr OF SPACE AnDPrOVIDE VEry LIttLE rOOM FOr ErrOr. tHE FUnCtIOn OF tHE PHACO FLUIDICS
IS tO bALAnCE tHE InFLOw AnD OUtFLOw OF FLUID In OrDEr tO MAIntAIn tHEwOrkIng SPACE, brIng CAtArACt MAtErIAL tO tHE PHACO tIP, AnD PrEVEntCOLLAPSE OF tHE EyE. OPtIMIzIng tHE PHACO FLUIDIC SEttIngS IS InStrUMEntALtO tHE EFFICIEnCy AnD SAFEty OF PHACOEMULSIFICAtIOn SUrgEry.
With a typical peristaltic phaco machine plat-
form, the most common type in the US mar-
ket, there are only a few parameters that are
adjustable: the bottle height, the ow rate, the maxi-
mum vacuum level, and the phaco needle size.
Perhaps the most important parameter is the selection
of phaco needle size. From our previous lesson, we re-
call that the difference in ow between a larger bore
needle and a small bore needle varies exponentially
due to Poiseuilles Equation. In summary, the smaller
bore phaco needles are suited for high-vacuum, low-
ow uidics, while the larger bore needles are better
suited for high-ow, low-vacuum uidics. The analogy
of drinking a milkshake via a small bore cocktail straw
versus a larger bore drinking straw works well to il-
lustrate this point.
The ow rate for a peristaltic machine is typically giv-
en in cc of uid per minute. This is determined by the
rate at which the peristaltic rollers milk the uid along
the outow tubing. With the phaco needle unobstructed
the maximum ow rate is achieved and in large part,
determines the speed at which things happen in the eye.
Upon occlusion of the phaco needle with cataract ma-
terial the ow rate declines and approaches zero. The
ow rate determines the speed at which things happen
in the eye during phacoemulsication.
The bottle height determines the inow rate of uid into
the eye. Very much like a water-tower in a small town,
the height of the uid above the eye creates a force-
ful infusion of uid via gravity: the higher the infusion
bottle, the greater the inow pressure and inow rate.
With an unobstructed phaco needle, the ow rate is at
the maximum, but the vacuum level is very lowvery
far from the maximum vacuum level that the surgeon
has selected. The vacuum level in a peristaltic-based
system is only achieved upon occlusion of the phaco
tip. (Figure 1) The higher the vacuum, the greater the
holding powerand the holding power is used to xate
the cataract while we mechanically chop it. The effect
of the vacuum level varies with the bore of the phaco
needle due to the effect of surface area. The larger the
cross-sectional surface area of the phaco needle, the
greater the holding power given the same amount of
vacuum. The vacuum level determines the holding
power or grip of the phaco tip onto nuclear pieces.
OPTIMIzINg yOUR SETTINgS
In order to optimize the phaco uidic settings, it is im-
portant to match the parameters to the technique and
the surgeons preference.
The rst decision is the selection of phaco needle size,with the most common sizes being the smaller-bore
0.9mm needle and the larger bore 1.1mm needle size.
If your preference is a quicker procedure with rapid
nucleus removal, the larger 1.1mm needle size is pre-
ferred since it will give a signicantly greater ow rate.
If your preference is a slower but more controlled pro-
cedure, then the smaller-bore 0.9mm needle is more
suited to your technique.
The bottle height determines the inow of uid into the
eye. In order to help prevent surge, it is important to
keep the inow of uid greater than the outow of uid
at all times. The inow of uid comes from only one
source, the bottle of balanced salt solution, while the
outow of uid comes from two sources, the suction
via the phaco needle and the leakage from the incisions.
If, at any time, the outow out-strips in the inow, the
eye will collapse and there is a high likelihood of pos-
terior capsule rupture. It is often advantageous to start
with a high bottle height to ensure a sufcient inow
of uid, and then to taper it downwards to minimize
the posterior displacement of the lens-iris diaphragm
due to the infusion pressure. If you sometimes notice
corneal striae and anterior chamber instability during
your surgery, you may benet from increasing the bot-
tle height.
For phaco chop, holding power of the nucleus is impor-
tant in order to securely xate it while using the chopper
to mechanically disassemble the nucleus. This requires
a relatively high vacuum, such as 200-250 mmHg with
the 1.1mm needle, or 300-400mmHg with the 0.9mm
needle. Once the nucleus has been broken into smaller
fragments, the speed at which the fragments are attract-
ed to the phaco tip is determined by the peristaltic ow
rate, with 20cc/min being very slow and 50cc/min be-
ing very fast. The same vacuum and ow rate settings
can be used for the entire nucleus removal procedure
during phaco chop.
For divide-and-conquer, there are two distinct parts
of nucleus removal: sculpting of the nucleus and then
quadrant removal, and different uidic settings are
required for each. For grooving and sculpting of the
nucleus, the work is being done by the ultrasonic en-
ergy and thus the ow and vacuum settings are quite
low just enough to aspirate the nuclear material re-
moved from each forward stroke of the phaco probe.
A vacuum level of less than 100mmHg and a ow rate
of less than 30cc/min is sufcient for this purpose. For
quadrant removal, a moderate amount of holding pow-
er is required to bring each quadrant into the phaco tip.
Using a higher vacuum level of 200-300mmHg and a
ow rate of 30-50cc/min, depending on the needle size,
is typically sufcient for this purpose.
With knowledge of the concepts behind the variables,
it is easy to tailor the uidic settings to the surgeon
and technique. Understanding the concepts behind the
phaco uidic settings is instrumental in optimizing the
parameters for increasing the efciency and safety of
your phaco technique.
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lesson 04
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WoRld RepoRt cme seRIes phaco fundamentals
Fundamentals ofUltrasonicPhaco PowertHE PHACO ULtrASOUnD PrObE DELIVErS EnErgy IntO tHE EyE tHAt CAn
bE USED tO brEAk UP tHE CAtArACt tO FACILItAtE EMULSIFICAtIOn AnDASPIrAtIOn. It ACCOMPLISHES tHIS by VIbrAtIng At A FIxED FrEqUEnCy wHEntHE FOOt-PEDAL IS DEPrESSED tO POSItIOn tHrEE. wHEn wE tItrAtE tHEAMOUnt OF ULtrASOUnD EnErgy wE PLACE IntO tHE EyE, wE ArE kEEPIngtHE FrEqUEnCy COnStAnt bUt wE ArE InCrEASIng tHE StrOkE LEngtH AnDtHErEFOrE, tHE tOtAL AMOUnt OF EnErgy.
The stroke of the phaco needle creates a mechani-
cal impact as the metal phaco needle hits the cata-
ract material. It also creates cavitation and implo-
sion as a microvoid is created just in front of the phaco
needle. A uid and particle wave is propagated into the
cataract material, and heat is created as a by-product. It
is important to avoid choosing phaco power settings that
cause excessive heat build-up as this can burn the cornea
and damage the delicate ocular structures.
The phaco pinch test is a simple way to determine if
your ultrasound power settings are likely to cause an
incision burn in the eye. During wet lab testing, pro-
gram your selected settings into the phaco machine,
remove the protective silicone sleeve from the phaco
needle, grasp the needle between your ngers, and
push the foot-pedal all the way down. If your settings
cause excessive heat build-up, the needle will get hot
and may even burn your ngers. But its better to singe
your ngertips than fry your patients cornea.
During surgery, the phaco machine keeps track of the
average phaco power, given as a percentage of maxi-
mum, as well as the total time during which phaco ul-
trasonic power was delivered. These are displayed as
U/S AVE, which stands for ultrasound average and
EPT, which is elapsed phaco time.
We can measure and compare the amount of phaco en-
ergy that we use in surgery by calculating the APT: Ab-
solute Phaco Time. This is done by multiplying the U/
S AVE by the EPT, which the phaco machine does
for us automatically, and it displays as the APT.
It makes sense that if you deliver 15 seconds of energy
at 100% power, it is about the same as 30 seconds at
50% power, or 60 seconds at 25% power. This is be-
cause for each of these three examples, the APT (Abso-
lute Phaco Time) is 15 seconds.
It is important to give as little ultrasonic phaco energy
as possible during the cataract surgery. The ultrasonic
energy can easily damage the corneal endothelial cells,
and excessive phaco energy can cause pseudophakic
bullous keratopathy and corneal decompensation. The
most important way to decrease the APT is to use a me-
chanical method of nucleus disassembly such as phaco
chop. This is far more efcient than techniques like di-
vide-and-conquer, resulting in less energy delivery as
well as shorter operative time.
To maximally decrease the APT, we need to decrease
both the average phaco power and the phaco time. The
average phaco power can be decreased by limiting the
foot pedal depression in position three or by decreasing
the maximum phaco power level on the machine.
The phaco time can be decreased by applying the ul-
trasonic power when cataract pieces are at the phaco
tip and are not aspirated by the vacuum forces alone.
Additionally, phaco time can be reduced by deliver-
ing smaller pulses or bursts of phaco energy instead
of continuous ultrasound. This method of breaking up
the ultrasonic energy into smaller packets of pulses and
bursts is called phaco power modulation and it will be
the subject of the next lesson.
With optimized ultrasonic phaco power parameters, it
is possible to remove cataracts with less than 1 second
of absolute phaco time, yielding immediate clear cor-
neas and happy patients.
lesson 05
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F 3 F 4
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WoRld RepoRt cme seRIes phaco fundamentals
Continuous, Pulse,And Burst PhacoModestHE bASIC POwEr SEttIngS ArE COntInUOUS, PULSE, AnD bUrSt. In tHE
COntInUOUS POwEr SEttIng, COntInUOUS EnErgy IS DELIVErED wItH VArIAbLEPOwEr DEPEnDIng On HOw LOng tHE FOOt PEDAL IS DEPrESSED. tHE MAxIMUMPOwEr SEttIng CAn bE PrESEt AnD tHEn OnE HAS COntrOL OF tHE MAxIMUMAMOUnt OF PHACO POwEr DELIVErEDtHE LOngEr tHE FOOt PEDAL ISDEPrESSED, tHE grEAtEr tHE PHACO POwEr.
In the pulse mode, the pulses of energy delivered
have variable power depending on how long the
foot pedal is depressed. The more time it is de-
pressed, the greater the power of each sequential pulse
of energy. The dening feature of pulse mode is that
after each pulse of energy delivered, there is a period
of time in which no energy is delivered between in-
creasing periods of energy, the off period. Alternat-
ing between the on and off pulse, reduces heat and
delivers half the energy into the eye.
Finally, in burst mode, each burst of energy has the same
power but the interval between each burst increases as
the foot pedal is depressed: The further the foot pedal
is depressed, the shorter the off period between each
burst. As a result, at maximum foot pedal depression,
the bursts of energy will become continuous delivery of
energy. When referring to modulations of phaco pow-
er, the terms burst and pulse may seem similar, but
they refer to two entirely different concepts.
Surgeons are familiar with the concept of continuous
phaco energy which is delivered in a linear fashion:
as the phaco foot-pedal is depressed, the energy level
increases. Pulse mode simply gives the same linear
control of phaco energy, however the energy is always
phaco machine to aspirate the cataract and then give
small bursts of phaco energy only when necessary. Be-
cause we can program these bursts of phaco power to
be very short (as quick as a few milliseconds), we can
effectively give hundreds of tiny bursts and still total
less than 1 second of total phaco time.
Because the phaco foot-pedal now controls the rest in-
terval between identical bursts, we do not have linear
control of the phaco power level. For this reason, it is
important to use a lower phaco power setting when
using burst mode as compared to pulse or continuous
modes. When the foot-pedal is maximally depressed,
the rest interval between bursts is zero and the phacoprobe essentially delivers continuous energy.
For surgeons using a divide-and-conquer technique of
surgery, the foot-pedal can be maximally depressed
during grooving, thereby delivering continuous phaco
energy to facilitate sculpting of the nucleus. Then to
remove the quadrants, the foot-pedal is only partially
depressed in position 3 so that only bursts of phaco
power are used for segment removal. Finally, for the
epi-nucleus removal, the foot position 3 is barely en-
tered, and just a few bursts of energy are delivered for
removal of the softer cataract portions.
Most phaco machines have two settings for burst mode:
single burst and multiple burst. Single burst delivers
just one single burst of energy, for burying the phaco
probe into a nucleus for chopping. I do not ever use this
mode, but instead prefer multiple burst mode because I
can still deliver just one single burst by barely entering
foot-position 3, and I still have the ability to deliver
many more bursts and varying intervals with further
foot-pedal depression.
For my technique of quick-chop, I typically use just
one phaco setting: Multiple burst mode, with a burst
time of 20 milliseconds, a power of 10%, and an end-
point duty cycle of 50%. This means that I can give
50 of these identical bursts at 10% power to equal just
one second of continuous phaco at 10% power. Or in
absolute terms, I can give 500 of these identical bursts
at 10% power to equal just one second of continuous
phaco at 100% power. It comes as no surprise that most
cataracts can be removed with an energy equivalent
that is less than 2 seconds of absolute power at 100%.
lesson 06
delivered in pulses. Burst mode denes a specic and
identical burst of phaco energy, then as the foot-pedal
is depressed, these identical bursts of energy are deliv-
ered more rapidly, until the interval of time between
bursts is innitely small.
Burst mode allows a true phaco-assisted aspiration of
the lens nucleus. We use the vacuum and uidics of the
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F 2, 3, 4
F 1
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lesson 07
Hper SettinstHE rAngE OF PrOgrAMMAbILIty OF tHE PULSE AnD bUrSt PHACO SEttIngSHAS ExPAnDED COnSIDErAbLy. wHILE PrEVIOUS gEnErAtIOnS OF PHACOPLAtFOrMS HAD PULSE rAtES OF UP tO 20 PULSES PEr SECOnD, tHE nEwErgEnErAtIOn MACHInES HAVE tHE AbILIty tO DELIVEr UP tO 120 PULSES PErSECOnD. SIMILArLy, tHE OLDEr MACHInES HAD bUrSt wIDtHS AS nArrOw AS 30MILLISECOnDS, wHILE tHE nEw PLAtFOrMS ArE AbLE tO DELIVEr bUrSt wIDtHSAS FInE AS JUSt 4 MILLISECOnDS.
The advantage of this upgraded range of program-
mability is the smoothness and precision of pow-
er delivery. With the standard settings in pulse
mode, where each pulse is as long as each rest period,
the pulse mode can deliver good cutting power with half
the energy of continuous phaco energy. [ F 1 ]
The more pulses per second we can give, the smoother
the power delivery will bevery similar to serrations
on a knife. If we want to harness the sculpting and cut-
ting ability of the phaco hand-piece for grooving of
the cataract nucleus, it makes sense that a knife with a
smooth blade would cut well. A coarsely serrated knife
with large, widely spaced serrations would not cut as
smoothly. However if we use a very nely serrated
knife, it would likely cut the best of all. Using a very
high pulse rate of 100 or more pulses per second results
in the cutting ability of a very nely serrated knife, yet
delivers half of the energy of continuous phaco power.
[ F 2 ]
Hyper settings in burst mode allow ner and more pre-
cise delivery of bursts of phaco power. If we use con-
tinuous phaco energy mode and try to use our foot to
deliver small bursts of phaco power, the best we can
do is about a half-second of energy per pulse, which is
500 milliseconds. Using the newer hyper settings we
can set a burst mode as small as 4 milliseconds, which
is 125 times ner and more precise than using manual
control by the surgeon.
Modern surgery is primarily phaco-assisted aspira-
tion of the nucleus. The majority of the forces that are
used to remove the nucleus from the eye are uidic
forcesthe ow, aspiration, and vacuum forces. The
ultrasonic power delivery is there to assist the uidics
once a denser piece of nucleus is encountered. My pre-
ferred setting for phaco surgery is burst mode, with a
very ne burst width. As the pedal is depressed further
in foot-position 3, the rest interval between bursts de-
creases until the burst width and rest interval are equal,resulting in a 50% duty cycle. The effective number
of bursts per second increases as the rest interval de-
creases and using a burst width of 5 milliseconds and
allowing 5 milliseconds of rest between each burst, the
maximum number of bursts per second is 100. (Math: 1
second / 10 millisecond cycle = 100 bursts per second).
This results in being able to effectively control the duty
cycle and the burst rate per second at the same time via
the foot-pedal.
For surgeons who wish to continue to perform their
standard technique of phaco-emulsication, simply
changing from continuous phaco power to a hyper
pulse rate of 100 pulses per second will allow them
to cut the energy delivery in half. This halving of the
ultrasound energy will result in less endothelial cell
damage, less heat production, and clearer corneas and
sharper vision immediately post-op. For surgeons who
perform the divide-and-conquer method of nucleus dis-
assembly, make the switch to a hyper pulse mode and
you will immediately perform better surgery without a
change in your technique.
Changing the number of pulses per second does NOT
change the amount of power delivered into the eye.
Whether we give 2 pulses per second or 8 pulses per
second, note that the total energy, as represented by the
green blocks, is the same. [ F 3 4 ] The same
applies when we compare 10 pulses per second to 100
pulses per second. The reduction in the amount of en-
ergy delivered is due to the ratio of the on:off pulses,
which is known as the duty cycle. In our next lesson,
we will explain duty cycles and their effect on phaco
power delivery.
F 1
F 2, 3, 4
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LESSON 08
Variable Dut CclewHEn wE CHOOSE A MODE SUCH AS PULSE MODE, wHICH ALtErnAtES PHACOPOwEr PULSES wItH PErIODS OF rESt, tHE DEFAULt rAtIO IS 50:50.tHIS IS CALLED A 50% DUty CyCLE, AS EACH COMPLEtE CyCLE IS COMPOSED OFEnErgy On FOr 50% OF tHE tIME, tHEn EnErgy OFF FOr 50% OF tHE tIME.tHIS DEFAULt rAtIO CAn bE CHAngED tO ALtEr tHE rAtIO OF ULtrASOUnDEnErgy tO tHE rESt IntErVAL.
Ultrasound energy creates helpful cavitation and
mechanical forces that are used to break up
the cataract nucleus; however, this energy also
can create signicant heat. The jack-hammer effect of
ultrasound energy can cause repulsion of the nuclear
fragments from the phaco tip. It is helpful to alternate
periods of phaco energy with rest periods, as the rest
periods are when we achieve cooling of the phaco
needle and aspiration of the nuclear fragments. If we
change the ratio of the on period, when ultrasound en-
ergy is delivered, to a shorter duration, then we can fa-
vor the aspiration and cooling of the phaco needle over
the heat generation and jack-hammer repulsion effects
of the ultrasound. [ F 1 ]
To program in a change in this ratio, there are two dis-
tinct methods: entering a new duty cycle or direct pulse
programming. For example, if I am using 10 pulses per
second and Id like to slightly reduce the ultrasound
energy, I can decrease it from a 50% duty cycle to a
40% duty cycle. This can be done by dropping the duty
cycle ratio as seen on the control panel of the phaco
platform. Alternatively, I can delineate the specic on
and off periods for each cycle, with an on-time of 40
milliseconds followed by an off-time of 60 millisec-
onds, I will achieve the same resulta total cycle time
of 100 milliseconds, with 10 pulses per second and a
40% duty cycle. [ F 2 ]
In the pulse mode, the default duty cycle is 50%. [ F
3 ] For instance, the pulse is on for 250 msec and off
for 250 msec. The benet of the new power modulation
software is that the duty cycle can be changed. For ex-
ample, we may select a duty cycle of 20%, which results
in 100 msec on and 400 msec off, giving a ratio of
20:80. [ F 4 ] We can then harness the benets of a
lower duty cycle which results in longer cooling time for
the phaco needle, thus decreasing the amount of phaco
energy delivered to the eye. In addition, during the ex-
tended off time, no energy is delivered and nuclear
fragments can be easily aspirated.
When do we want higher or lower duty cycles? The
answer depends on the phase of surgery. For sculpting
the nucleus, such as with the technique of divide-and-
conquer, we need to deliver sufcient energy to be able
to cut the grooves. This requires a duty cycle of about
40-60%. Once we have the grooves placed in the nucle-
us and we have cracked it into quadrants, we can use a
lower duty cycle during the phaco-assisted aspiration of
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F 3, 4
the quadrants. For this quadrant removal, a lower duty
cycle of 20-40% can be used since the principal force for
nucleus removal is the uidics and not the ultrasound.
Using the variable duty cycle programming allows the
surgeon to deliver just the right amount of ultrasound
energy during each phase of surgery. The concept to re-
member is that a higher duty cycle results in better cut-
ting power but increased heat generation and more ener-
gy-related damage to the corneal endothelium. Using the
lower duty cycle allows more uidic aspiration of nucle-
ar fragments while minimizing heat and phaco power,
resulting in clear corneas immediately after surgery. And
we all know that clear corneas on post-op day one makefor good visual acuity and very satised patients.
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lesson 09
Variable Rise TimeAnd Custom SettinskEEP In MInD tHAt tHE ULtrASOnIC PHACO POwEr IS A rEPULSIVE FOrCE:LIkE A JACk-HAMMEr, tHE PHACO nEEDLE MOVES bACk AnD FOrtH IntO tHECAtArACt At A FIxED FrEqUEnCy (bEtwEEn 28,500 tIMES/SECOnDAnD 40,000 tIMES/SECOnD, DEPEnDIng On tHE PLAtFOrM).
wEVE ALL SEEn tHIS DUrIng SUrgEry AnD OFtEn CALL It CHAttErwHEn tHE ULtrASOnIC POwEr MECHAnICALLy PUSHEStHE nUCLEUS OFF tHE PHACO tIP.
or burst width is so short that there is insufcient time
to fully ramp up each packet of phaco energy. For ex-
ample, if it takes 40 milliseconds to ramp-up the power
from zero to the preset level, but the dened burst width
is just 25 milliseconds, the desired phaco power level
will not be achieved.
SUggESTED SETTINgS FOR SURgEONS
First, remember to keep your phaco needle and all
vacuum and ow levels the same as to what you are ac-
customed. Also, no change in your surgical technique is
needed. The only thing that we will be changing is the
way that the phaco power will be delivered.
If you are accustomed to continuous phaco mode, you
will likely have an easy time starting with a hyper-pulse
mode of 60-120 pulses/second, initially at a 50% duty
cycle, and using the same maximum phaco power that
youre used to. This one simple change will likely cut
your total phaco time and energy in half with virtually
no effect on your technique.
If you are accustomed to a pulsed phaco mode, you will
have an easy time staying with about the same number
of pulses per second and keeping your maximum phaco
power the same, while decreasing your duty cycle to
25-45%. You can then implement a variable rise time in
order to further decrease the total phaco time and ener-
gy and enhance purchasing power and follow-ability.
Phaco chop surgeons will have an easier time adapt-
ing to hyper-burst mode. Keeping in mind that you will
be controlling the interval between identical bursts via
the third position, you should keep the maximum phaco
power level relatively low. You will be unable to vary
the percentage power level with your foot pedal, so set-
ting a maximum level of 10-30% is suggested. Keep
the burst width short, between 20 and 80 milliseconds,
and make sure that you use an end-point duty cycle of
50%. Depending on your machine, you may have to en-
ter this as a minimum burst interval which should be
set equal to your burst width in milliseconds to achieve
the effective end-point duty cycle of 50%.
You can further tailor your settings to better suit your
technique and your patient population, without chang-
ing your surgical technique. Transitioning to the new
phaco power modulation software is an easy way to
improve your surgical outcomes and efciency while
decreasing the heat and energy placed into the eye.
To reduce the repulsive force of phaco we can
decrease the phaco power, but this isnt always
the best answer, particularly when a nucleus is
dense and requires more phaco power for emulsica-
tion. Instead, if we initially attack the nucleus with
lower power, then hold on to it with the vacuum uid-
ics of the phaco machine, we can ramp up the power to
a higher level. The new phaco power modulation soft-
ware on most platforms allows this automatically, with
millisecond precision.
Burst and pulse modes deliver square-wave energy by
default, which means the power goes from zero to the
preset level immediately, and the resulting waveform
on the oscilloscope looks like a square. With a variable
rise time, we can have the phaco energy ramp-up over
the course of each individual pulse or burst, resulting in
a ramped wave. [ F 1, 2, 3 ]
This ramping up of the energy allows better follow-
ability of the nuclear pieces and less chatter at the phaco
tip, and it results in less energy and less heat delivered
into the eye. There are situations where it is difcult to
use a variable rise time, such as when the pulse width
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F 1
F 2 F 3
F 4
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WoRld RepoRt cme seRIes phaco fundamentals
lesson 10
CreatinA Clear-CornealCataract IncisionFOr PHACOEMULSIFICAtIOn, tHE USE OF CLEAr-COrnEAL InCISIOnS HAS bECOME
VEry COMMOn FOr MAny rEASOnS: tHEy ArE EASy tO COnStrUCt,tHEy PrOVIDE gOOD ACCESS tO tHE CAtArACt, AnD tHEy SEAL wELL.
In a typical phacoemulsication, two incisions are
created: the main incision and a secondary incision,
the paracentesis. These are typically placed ap-
proximately 60 to 90 degrees apart, with the non-domi-
nant (usually left) hand at the paracentesis, while the
dominant (usually right) hand is at the main incision.
In addition, the main incision can be made at the steep
axis so as to help reduce astigmatism at this meridian.
Incisions can be made stepped or straight: a stepped inci-
sion has 2 or 3 different planes, while the straight inci-
sion has just one plane. There may be advantages with
the stepped incisions, particularly if a hinge is created.[
F 1 ]
However, all of these incisions have one thing on com-
mon: they have long tunnel lengths.[ F 2 ]
The longer tunnel lengths allow better sealing of the
incision and less induction of astigmatism, and for
these reasons, making a more square incision is rec-
ommended. The longer tunnels may have more of an
oar-lock feeling, where maneuverability within the
eye is somewhat limited, however this is usually quite
manageable.[ F 3 ]
The shorter tunnel lengths cause more astigmatic at-
tening at that meridian and they do not seal nearly as
well. While there is less oar-lock effect, the more
posterior entrance into the anterior chamber may be
prone to iris prolapse through the incision.[ F 4 ] If
there is any doubt as to the water-tightness of the inci-
sion, it is better to place a suture to close the incision.
To suture the corneal incision, 10-0 nylon or 10-0 vic-
ryl is typically used, with the knot rotated to bury it
within the corneal stroma. The suture should be placed
about half to two-thirds of corneal depth and well cen-
tered on the incision. The tension should be enough to
seal the incision well, yet not so much as to induce a
large astigmatic effect.[ F 5 ]
For managing astigmatism, keep in mind that longer
tunnels have less effect and are considered astigma-
tism-neutral, while the shorter incision cause attening
and therefore are astigmatism-inducing.[ F 6 ]
Due to the increased surface area created from a longer
tunnel length, the longer incisions tend to seal much
better. [ F 7 ]
The intra-ocular pressure at the end of the surgery ex-
erts an outward force which pushes on the inner part of
the incision and keeps the corneal layers tightly sealed.
Patients may experience some initial post-operative
hypotony, so ensuring a long tunnel length will help
prevent any incisional leakage. Phaco surgery is com-
monly referred to as sutureless, but the prudent sur-
geon knows the value of a well-placed suture when the
situation dictates. [ F 8 ]
Well-constructed clear corneal incisions are an integral
part of modern-day phacoemulsication and a tech-
nique that cataract surgeons should know.
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F 1
F 7, 8
F 2, 3, 4, 5, 6
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lesson 11
If you look closely at the phaco tipat the phaco
needle itselfyou will see that it is cut at an angle,
thus giving a bevel. Most phaco needles that are
used today have a bevel to increase their utility and
usefulness during cataract surgery.
The strength of the grip is inversely related to the ne
motor control: the lighter the grip, the better the control.
If I had a stack of ten sheets of paper inte rspersed with
sheets of carbon paper, and then I asked you to write
forcefully enough so that even the bottom carbon copy
was legible, you would utilize a very strong grip. But
the quality of the writing would be very poor. On the
other hand, if I asked you to write as neatly as possible
on a single sheet of paper with your prettiest calligra-
phy writing, you would use a very ne, light grip. This
ne, light grip is best suited for the phaco probe and
for intra-ocular surgery.
The position of the hands should be at the pat ients eye
level, with both hands resting comfortably with the
shoulders relaxed. The hands can lightly rest on the
patients draped face/head or on a separate wrist-rest.
The control of the phaco probe and intra-ocular instru-
wE SPEnD MAny yEArS wrItIng AnD DEVELOPIng tHE nEUrAL PAtHwAyS FOrFInE HAnD MOtOr COntrOL bEFOrE wE EVEr PICk UP A PHACO PrObE.It IS EASIEr AnD MOrE nAtUrAL FOr MOSt PHACO SUrgEOnS tO HOLD tHE PHACOPrObE LIkE A PEn, PArtICULArLy gIVEn tHE PrObES PEn-LIkE SHAPE.
Hand Position& Pivotin
ments is primarily from the ngers and somewhat from
the wrists; gross movements of the forearms, arms,
elbows, and shoulders are not well suited for ocular
surgery.
PIVOTINg
The instruments, particularly the phaco probe, should
oat within the incision. There should be no forceful
pushing on any a spect or edge of the incision. With
any instrument, distortion of the incision can deform
the cornea and impair the view within the eye. With
the delicate balance of uidics in phacoemulsication,
distortion of the incision can lead to excessive leak-
age and an unstable chamber leading to a high risk of
capsule rupture. Finally, remember that the ultrasonic
energy from the phaco probe can produce a signi cant
amount of heat and that forcefully pushing the phaco
needle against the edge of the incision can burn the
cornea in a matter of seconds. Floating within the inci-
sion is critical.
In order to maneuver within the eye without pushing
on the incision, we need to pivot our instruments. The
action is very similar to the rowing action in a row boat:the paddle is placed within an oarlock (analogous to our
incision), and in order to push water away from us with
the paddle, we pull the handles toward us. [ F 1 ]
In the eye, when you want to move the phaco tip down-
ward, you do not push down on the incision. Rather, you
lift the back end of the phaco probe upward, which will
pivot the probe within the incision, a nd the phaco tip
will move downward. [ F 2, 3 ] This is accomplished
without deforming the incision; thus, the chamber stays
formed and the cornea remains undistorted.[ F 4 ]
KEEPINg THE EyE IN PRIMARy gAzE
With two incisions, the main incision and the para cen-
tesis, and two instruments within the eye, the patient
will not be able to move the eye even under topical
anesthesia. This two-point xation is another advan-
tage of two-handed surgery. One-handed techniques
of phacoemulsication are relatively out-dated, and, as
such, I do not teach them to my residents or students.
The surgeons best view and most maneuverable st ate
is when the eye is in primary gaze while the patient is
in the supine position. By oating in the incision, we
can keep the eye in this primar y position. Any forceful
pushing of the instruments within the eye will cause
the eye to move away from the force vectorusually
towards the medical canthus. This is dangerous since
it limits the surgeons view and maneuverability within
the eye.
Adjust your hand position so that there is no pushing
on any aspect of the incision and you will nd that the
eye will return to primary gaze. In cases of topical an-
esthesia, the patient can assist you further by looking
directly at the microscope light.
In summary, keep the hand position relaxed and com-
fortable, keep the instrument grip ne and delicate,
keep the instruments oating gently within the inci-
sion, and keep the eye in primary gaze by pivoting the
instruments.
Oar lock
Hand Control : Pivot in the incision
Pivot Action with Oars in a Rowboat
Hand Control : do NOT push down!
Lose Viscoelasticand Fluid
Very ShallowAnterior Chamber
Hand Control : PIVOT in the incision
Keeps ViscoelasticAnd Fluid in Eye
Good, DeepAnterior Chamber
Hand Control : PIVOT in the incision
PUSHING
=BAD
PIVOTING
=GOOD
Corneal Distortion
and Wrinkling
Cornea is Clear
and Undistorted
F 2, 3, 4
F 1
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lesson 12
The most common bevel is a 30 degree bevel,
which means that the angle at which it is cut is
30 degrees relative to the long axis of the needle.
There are also 45 and 90 degree tips available, and other
varieties where the shaft itself may be bent or the tip may
have a are. These varieties provide different options
during nucleus removal, but I still recommend starting
with a traditional 30 degree tip during the earlier stages
of the learning.
Bevel Position;Incision SpacinIF yOU LOOk CLOSELy At tHE PHACO tIPAt tHE PHACO nEEDLE ItSELFyOU wILL SEE tHAt IS CUt At An AngLE, tHUS gIVIng A bEVEL. MOSt PHACOnEEDLES tHAt ArE USED tODAy HAVE A bEVEL tO InCrEASE tHEIr UtILIty AnDEFFICIEnCy DUrIng CAtArACt SUrgEry.
The beveled phaco needle can be positioned in a bevel-
up, bevel-sideways, or bevel-down orientation. The
bevel-up position is best suited to grooving techniques,
where the phaco needles action is similar to that of an
ice cream scoop. The goal is to only partial ly ll the tip
of the needle with nuclear material as the groove is made.
The bevel-sideways position is effective for quadrant
removal, with the opening directed towards the la rgest
part of the quadrant so that the energy is applied into the
cataractous material which would then tend to carousel
into the phaco tip. The bevel-down position is best suited
to achieving maximum grip of the nucleus.
To use a household vacuum cleaner to pick up a piece
of paper, you know that it is helpful to fully occlude the
tip in order to achieve maximum holding power. The
same is true for phacoemulsication with a peristaltic
pumpocclusion is required i n order to ach ieve the
preset maximum vacuum level and effectively hold the
nucleus. Once the nucleus is held rmly, it becomes
relatively easy to perform phaco chop or other methods
of nucleus disassembly.
The approach from a typical clear corneal incision down
towards the cataract nucleus is an angle of 30 degrees
perfectly suited for our 30 degree phaco needle in the
bevel-down position. As soon as the phaco nee dle ap-
proaches the cataract, it is very easy to achieve occlusion,
and rmly hold the nucleus in preparation for chopping.
The bevel-up position would not achieve occlusion a nd,
thus, the holding power would be weak as the vacuum
level would never reach the preset maximum with our
peristaltic pump.
By holding the phaco probe like a pen, with a light and
delicate grip, you should be able to maneuver it easily
from the bevel-down to the bevel-up position by simply
rolling the tip between your ngers.
INCISION SPACINg
In a previous lesson we explained the method of making
a proper clear corneal incision for our phaco probe. Keep
in mind that we need to act ually create two incision in
the eye: a small paracentesis of approximately 1.0mm (or
less) in width, and a main incision with a width of about
2.5-2.8mm. For ease of hand position and maximum
maneuverability within the eye, I prefer to have these
incisions about 60 degrees apart, with the main incision
for my dominant right hand and the paracentesis incision
for my left hand.
Hand Control : Bevel Up & Down
Pivot Tip with Bevel UP
Good for Sculpting / Grooving
Hand Control : Bevel Up & Down
Bevel UPOcclusion NOT AchievedPOOR grip for chopping
Bevel DOWNOcclusion IS Achieved
GOOD grip for chopping
Bevel UP - Regular
Bevel DOWN - Upside Down
Hand Control : Bevel Up & Down
30
30
Make
Paracentesis
Make
Corneal Incision
Cataract SurgeryIncisions
60
About 60 Between Incisions
ParacentesisAIM *FLAT*(plane of iris) Main Incision
AIM *UP*(plane of cornea)
The paracentesis can be made at and parallel to the iris
since it is such a small incision. While we could certainly
make it in the corneal plane to achieve a longer tunnel
length, this could limit movement of our second instru-
ment within the eye. Because the main clear corneal
incision is much wider, it becomes more important to
have a longer tunnel length, therefore it is made while
aiming up in the plane of the cornea.
Having the correct placement of the incisions and the
correct bevel positioning of the phaco probe within the
eye, can make our surgery safer and more efcient.
F 1
F 2
F 3
F 4
F 5
F 6
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lesson 13
Foot Pedal ControlDurin Steps OfSurerDUrIng SUrgEry wE CLEArLy nEED PrECISE COntrOL OF bOtH HAnDS tO HOLD
InStrUMEntS AnD OPErAtE wItHIn tHE COnFInES OF tHE AntErIOr SEgMEnt.wE ALSO nEED tO COOrDInAtE FInE COntrOL OF bOtH FEEt, AS tHEy PLAy ACrUCIAL rOLE In COntrOLLIng tHE FOOt PEDALS.tHE trADItIOnAL PLACEMEnt IS tO HAVE tHE LEFt FOOt COntrOLtHE MICrOSCOPE FOOt PEDAL wHILE tHE rIgHt FOOt COntrOLStHE PHACO FOOt PEDAL.
The primary microscope controls are focus,
zoom, and centration. Additional functions in-
clude the ability to turn the microscope light
on/off as well as to adjust the brightness. The micro-
scope should be reset and centered at the beginning of
the case in order to provide a full range of adjustability.
Avoid high magnication for routine cases as this will
unnecessarily limit your eld of view.
The more important pedal during phacoemulsication
is the phaco foot-pedal as it controls the irrigation, as-
piration, as well as ultrasonic power delivery. Fine con-
trol of uidics and power can be achieved with prac-
tice. The three positions of the phaco foot-pedal are:
1-irrigation, 2-aspiration, and 3-ultrasound. Each step
is additive, so when we are in position 2, we have irri-
gation plus aspiration, and in position 3, we have irriga-
tion, aspiration, and ultrasound power delivery.
The irrigation in position 1 is either on or offthere
is no ability to titrate the amount of irrigation via the
foot-pedal. You will recall that the irrigation inow is
determined by the bottle height and the size of the inow
tubing. Taking the foot off the pedal completely is called
position zero since the phaco probe is doing nothing.
The aspiration in position 2 can be controlled in a linear
manner: the beginning of position 2 gives lower aspira-
tion and as you depress the pedal further into position
2, you get more and more aspiration. This is quite simi-
lar to the gas pedal on cars, where the acceleration is
proportional to the amount of pedal depression.
Position 3 also has the ability for linear control, where-
by progressively greater depression of the pedal gives
more phaco energy. Depending on the type of phaco
power modulation used, the foot pedal depression in
position 3 will give more ultrasound energy. In both
phaco continuous and phaco pulse mode, further de-
pression increases stroke length of the phaco needle.In phaco burst mode, further depression increases the
number of bursts per second by limiting the rest inter-
val between bursts.
FOOT-PEDAL POSITION
DURINg STEPS OF SURgERy
Before entering the eye with the phaco probe, the foot-
pedal should be in position 1 so that the irrigation uid
will prevent the eye from collapsing as the main inci-
sion is opened and the phaco needle is introduced into
the eye. A soft nucleus may be removed with simple
aspiration in position 2; however, any cataract with
signicant nuclear density will require ultrasound en-
ergy. To emulsify the cataract, the phaco probe should
deliver energy during the forward stroke. Then when
retracting the phaco probe, there is no need to deliver
energy, so we can go back to position 2 for aspiration,
or even position 1 for simple irrigation only.
Once we have a nuclear fragment or piece, we can use
aspiration in foot position 2 to bring the piece to the
tip in preparation for emulsication. Once the cataract
piece is right at the phaco tip, application of ultrasound
energy in position 3 will emulsify it.
The goal of modern cataract surgery is ultrasound-as-
sisted aspiration of the lens, where the primary means
of lens removal is aspiration, and ultrasound phaco en-
ergy is only given to assist. This will allow us to mini-
mize the amount of energy that is placed into the eye
and will result in better outcomes. Accurate foot pedal
control requires patience to master, but once learned,
it allows an increased margin of safety and efciency
during phacoemulsication.
Phaco Foot Pedal Function
Irrigation = 1
Aspiration = 2
Ultrasound = 3
Ultrasound on Forward Stroke
Ultrasound = 3
Before Entering the Eye
Irrigation = 1
Only Aspiration on Backstroke
Aspiration = 2
Aspiration to bring cataract to phaco tip
Aspiration = 2
Ultrasound when cataract is at phaco tip
Ultrasound = 3
F 1
F 2, 3, 4, 5, 6
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lesson 15
CapsulorhexisCreationDECADES AgO, tHE MEtHOD FOr CAtArACt SUrgEry wAS IntrA-CAPSULArExtrACtIOn, wHErE tHE EntIrE CAtArACt AnD ItS CAPSULE wHErE rEMOVEDFrOM tHE EyE. OUr tECHnIqUE HAS ADVAnCED DrAMAtICALLy, AnD nOw MOrEtHAn 99% OF tHE tIME wE rEMOVE JUSt tHE CAtArACtOUS MAtErIAL,
wHILE LEAVIng tHE CAPSULE AnD zOnULAr StrUCtUrES IntACt.HEnCE tHE nAME ExtrA-CAPSULAr ExtrACtIOn.
The evolution of capsulorhexis began with the
use of a needle to make multiple punctures in
the anterior lens capsule to create an opening
through which to access the cataract nucleus. While
this works, it makes for an unstable capsular bag and
predisposes to a higher complication rate. Today, our
preferred method is creation of the continuous curvilin-
ear capsulorhexis (CCC).
For most cases, our ideal capsulorhexis is a well-cen-
tered, round opening of the anterior capsule with a di-
ameter of about 5mm. This allows sufcient access to
the nuclear material, and at the end of the case it al-
lows secure placement of a standard posterior chamber
IOL within the capsular bag. The typical IOL has an
optic diameter of 6mm and our 5mm capsulorhexis is
therefore able to cover the edge of the optic and hold it
securely in position after the completion of surgery.
It is important to keep the anterior chamber well
formed and the anterior lens capsule attened during
the creation of capsulorhexis. This allows for greater
control and prevents run-off and radicalization of the
capsulorhexis and allows for more control. The two
keys to achieving this stable AC and at capsule are:
use a good cohesive viscoelastic and oat within the
incision. These measures prevents collapse of the an-
terior chamber. You will remember from previous les-
sons the importance of oating within the incision, not
distorting the eye, and pivoting the instruments.
STEP 1 To start the capsulorhexis, a single puncture
is made in the central part of the anterior lens capsule.
This can be done using a bent needle, called a cysto-
tome, or by using the tips of the capsulorhexis forceps.
My capsulorhexis forceps are marked with two lines, at
2.5mm and at 5mm, to facilitate creation of a capsu-
lorhexis with an exact 5mm diameter every time. When
the sharp tips of the forceps are poked into the center
of the anterior lens capsule, the 2.5mm mark delineates
the radius of our intended capsulorhexis.
STEP 2 To propagate the tearing of the capsulorhex-
is, it is important to keep the torn capsule folded over
as this allows the tear to proceed in a more controlled
manner. I recommend understanding the force vectors
required for capsulorhexis creation by practicing using
your ngers to tear large 10cm circles in newspaper.
This will highlight the importance of keeping the torn
capsule folded over.
STEP 3 As we proceed to tear the circular capsu-
lorhexis, we will notice that half way through the
rhexis, the 2.5mm hash mark of the forceps tip should
be in the exact center of the anterior capsule, and the
5mm hash mark should be at the outer edge of the cap-
sulorhexis. This ensures that we are tearing the proper
size capsulorhexis.
STEP 4 We complete the capsulorhexis using the same
technique, and the torn central remnant is removed
from the eye and discarded. If capsulorhexis radializes,
it is important to stop, inject more cohesive viscoelas-
tic, and try to bring it centrally once again. If it extends
too far radial and out to the zonules, you may not be
able to retrieve it, and in this case you can nish by go-
ing in the opposite direction with the capsulorhexis, or
by using the bent needle cystotome to place a series of
punctures in the intended areas.
Because it is a complete circle, the capsulorhexis pro-
vides a high degree of strength and stability to the cap-
sular bag and keeps the IOL secured centrally. This
assures a consistent post-operative refractive outcome
and happy patients.
Float within the Incision
Do not allow the anterior chamber
to shallow or collapse.
Step 1Dashed line isthe intendedCapsulohexisSize of 5.0 mm
Poke sharp tips of forceps
into the center of the
anterior lens capsule.The
first hash mark (2.5mm)
represents the radius of your
intended 5.0mm
capsulorhexis.
Step 2
Start the capsulorhexis,
keeping in mind the intial
position of the first (2.5mm)
hash mark as a guide.
Step 3
Half way through the
rhexis,the 2.5mm hash
mark should be in the
exact center,and the
5.0mm hash mark should
be at the outer edge ofyour capsulorhexis.
Step 4
End of the procedure - now
the capsulohexis has the
ideal 5.0mm diameter for
cataract surgery.
F 2, 3, 4, 5
F 1
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WoRld RepoRt cme seRIes phaco fundamentals
lesson 16
Hdrodissection andHdrodelineationOnCE tHE CAPSULOrHExIS HAS bEEn CrEAtED, It IS HELPFUL tO USE bALAnCEDSALt SOLUtIOn tO LOOSEn AnD SEPArAtE tHE CAtArACt In OrDEr tO FACILItAtEItS rEMOVAL. tHE twO PrIMAry tECHnIqUES ArE HyDrODISSECtIOn AnDHyDrODELInEAtIOn, bOtH OF wHICH ArE PErFOrMED USIng A bLUnt 27 gAUgE
CAnnULA On A 3CC SyrIngE FILLED wItH bALAnCED SALt SOLUtIOn.
Hydrodissection is performed between the cap-
sule and the cataract cortex in order to free
the adhesions of the cataract from the cap-
sular bag and allow it to rotate fully. Care is taken to
place the blunt ca nnula under the edge of the anterior
capsulorhexis and directed toward the lens equator.
You should stop shy of the lens equator as you do not
want to puncture the lens capsule or damage the zon-
ules. Keep the cannula steady so that it forms a tight
seal between the capsule edge and the cataract. If you
move too much and loosen this seal, the uid will re-
ux back along the path of the cannula rather than dis-
secting forward.
Next, gently press on the plunger of the syringe in order
to send the balanced salt solution around the posterior
aspect of the cataract. You want to see at least one uid
wave propagated around the cataract, and more waves
are better. As the waves propagate, they will loosen the
cataract from the capsular bag and some uid may be-
come trapped between the lens and the posterior cap-
sule. To release this uid, use the cannula to gently tap
on the center of the nucleus and the uid will be pushed
anteriorly. The key here is to be gentle so that no undue
force is used as this could cause the capsule to rupture
and the nucleus to sublux into the vitreous.
How much force is used? Very little, since the key is
slow and steady. To give you an idea of the force re-
quired, if you take the 3cc syringe with the 27-gauge
cannula and inject it outside of the eye, it would form
a gentle arc of uid that would extend only a few
inches. If your application of force causes the uid to
shoot across the room, you are being much too force-
ful. This requires a steady hand and a good sense of
uid control.
Hydrodelineation is employed by some surgeons to
separate the endo-nucleus from the epi-nucleus. The
central endo-nucleus is of a higher density and re-
quires more ultrasound energy to remove, while the
epi-nuclear shell is softer and easier to remove. This
is an optional step that is performed with the idea that
the epi-nuclear shell can act to protect the posterior
capsule during phacoemulsication of the endo-nu-
cleus. Many surgeons do not perform this step, and
instead prefer to remove the entire nucleus without
separating it into these layers.
To prevent the uid from the cannula from going be-
tween the capsule and the nucleus during hydrodelin-
eation (which was already accomplished during hy-
drodissection), the tip of the cannula should be placed
central relative to the edge of the capsulorhexis and
not beyond it. Dig the tip of the cannula into the nu-
clear material while keeping it within the connes of
the 5mm capsulorhexis. This will allow proper hydro-
delineation, and a successful uid wave will result in
the golden ring appearance at the area of separation
between the epi-nucleus and the endo-nucl eus.
Once the cataract has been freed from the capsule
with hydrodissection and split into endo-nuclear and
epi-nuclear sections with hydrodelineation, we are
ready to perform nucleus removal using aspiration
and ultrasound energy from the phaco probe.
Create a tight seal
With a tight seal,
the fluid should create
a forward fluid wave.
Hydro - dissectionBetween the Capsule
and the Cortex
Hydro - delineationBetween the Nucleus
and the Epi-nucleus / Cortex
F 1
F 2 F 3
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0 WoRld RepoRt cme seRIes phaco fundamentals
lesson 17
Concepts OfNucleus RemovaltHE ULtrASOnIC PHACO PrObE IS USED FOr JUSt A SIngLE PArt OF tHE SUrgEry:rEMOVAL OF tHE CAtArACt nUCLEUS. tHE rESt OF tHE PrOCEDUrE CAn bEPErFOrMED wItH MUCH SIMPLEr InStrUMEntAtIOn.bUt tHESE OtHEr StEPS OF tHE SUrgEry ArE CrItICAL,
AnD wItHOUt PErFOrMIng tHEM COrrECtLy, tHE tASk OF nUCLEUSrEMOVAL bECOMES qUItE DIFFICULt.
Cataract surgery is a delicate pyramid, where
each previous step provides the foundation
upon which the next step is performed. When
everything goes well, the result is a beautiful surgery,
an excellent visual outcome, and a very happy patient.
The cataract surgery success pyramid starts with good
patient selection, good anesthesia, good exposure and
draping of the eye, and good preparation by the sur-
geon. Our next level is making proper incisions of the
right size in order to keep the anterior chamber deep
and inated during surgery. With a well-formed ante-
rior chamber, a round, well-centered capsulorhexis can
be created with minimal stress to the zonules. This al-
lows for efcient nucleus and cortex removal and IOL
insertion. These incisions will then seal very well and
will be astigmatically neutral. With all of this together,
we end up with good vision and a happy patient.
The cataract surgery complication pyramid is not so
pretty and not so happy. If we st art with poor patient
selection, ineffective anesthesia, and inadequate ex-
posure of the surgical eld, we will run into problems.
These can be issues such as an improperly constructed
incision that leaks during surgery and causes anterior
chamber instability and attening. This makes the
capsulorhexis difcult and irregular with stress placed
on the zonules. We are then at much higher risk of a
broken capsule and vitreous loss. Then vitreous gets
trapped in the patients leaky incision. The patient de-
velops cystoid macular edema and a vision of 20/200
or worse. Both the patient and the surgeon are disap-
pointed.
Clearly, its important to make sure we are building
a cataract surgery success pyramid. Since most sur-
geons who read this lesson will already have signi-
cant experience with patient selection, anesthesia, and
draping of the surgical eld, we can focus our teach-
ings on concepts of nucleus removal.
The primary concept to remember is that we are per-
forming ultrasound-assisted aspiration of the cataract.
The phaco energy