IC-94 Management of Cataract in Challenging Cases
Dense Cataract Emulsification
Dr. Abhay R. Vasavada, MS, FRCS (England)
Iladevi cataract and IOL Research Center, Ahmedabad, India.
Emulsification of a dense cataract is demanding both for the surgeon and the patient.
The pivotal issues:
- Judicious use of ultrasound energy
- Longer surgical duration
- Infusion fluid in excess
- Plane of energy dissipation
- Division of leathery lens fibers
How can one reduce the consumption of ultrasound energy during emulsification?
(I) Use strategies that can deliver U/S energy thriftily:
 Preset low power
 Use interrupted energy: MicroBurst or Pulse,
(II) New technology :
 Tortional Ultrasound - OZIL Technology
The objective of the Torsional technology:
 Improve chamber stability
 Improved followability
 Reduce energy dissipation
 Reduce turbulence in anterior chamber
 Reduce fluid use
 Reduce surgical time
What is OZILTM Technology?
* It is based on Torsional Ultrasound.
* Frequency reduced from 40 kHz to 32 kHz ultrasonic movement of the phaco
tip.
* The tip oscillates 5.5º degrees (± 2.75º) from the left to the right.
* The 5.5º degrees of oscillations translates in approximately 90 microns of
stroke at the cutting edge (at end of tip).
Impact of Torsional ultrasound at incision
* At incision stroke is approximately ½ of it, 40 microns.
* There is less rise in temperature as the frequency is low and the excursions of
phacotip at the incision are small compared to longitudinal ultrasound.
Efficacy of Torsional ultrasound during emulsification
It has non-stop cutting action during left and right direction. It therefore has increased “Cutting”
efficiency.
Surgical strategy: “POSTERIOR PLANE PHACOEMULSIFICATION”
The surgical steps:
INCISION & RHEXIS: A clear corneal temporal incision of 2.2mm or 2.4 mm depending on the
astigmatism and a moderately sized anterior curvilinear capsulorhexis is fashioned.
FOUR-QUADRANT HYDRODISSECTION: Dense cataracts are frequently associated with corticocapsular adhesions, which can make rotation of the nucleus difficult or stressful after complete
cortico-cleaving hydrodissection. Four-quadrant hydrodissection or focal hydrodissection helps
cleave these adhesions.
Phacoemulsification is performed with the coaxial micro incision cataract surgery (CMICS) using
the tortional Handpiece - OZIL Technology on Infiniti Phacoemulsifier (Alcon Laboratories, Texas,
USA).
SCULPTING: A central, deep, wide, steep walled trench or a crater with a very thin posterior plate
provides space for fragment removal within the bag. With torsional ultrasound since the tip
oscillates from one side to the other, it cuts on both excursions, accomplishing the central trench
rapidly.
Points:
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Phaco tip with a Kelman configuration
Dispersive viscoelastic like Viscoat
An optimal preset ultrasound energy to prevent thrust to capsular bag and zonules
The end is indicated by a red glow that is appreciated through the thinned out posterior
plate: “light at the end of tunnel”.
DIVISION OF THE NUCLEUS: “Step By Step Chop In Situ & Lateral Separation” technique.
The technique:
The parameters that have been preset for the sculpting are modified for division of the nucleus
(table 1). The technique has five components:
1st: Achieving a vacuum seal
2nd: Chop in situ: Initiating a crack
3rd: Lateral separation
4th: Repositioning of the chopper
5th: Lateral separation
The phaco probe and the chopper are placed within the confines of the crater.
Achieving a vacuum seal: The phacoprobe advances towards the wall of the trench and attempts
to pierce it simultaneously depressing the foot pedal to the third position. This buries the tip into
the lens substance. The footswitch immediately switches from the 3rd position to the second
position and remains there till an occlusion. (Indicated by the machine as a ringing bell) is achieved.
This produces a vacuum seal resulting in an effective hold on the nucleus with the phaco probe.
Chop in situ: Initiating a crack: Chop in situ maneuver is performed. The chopper is placed close in
front of the phacotip. The chopper remains within the capsulorhexis and the vertical element is
depressed posterior (towards the optic nerve). The aim is to only initiate a crack and not to divide
the nucleus at a single stroke.
Lateral separation: In hard cataracts, the initial crack seldom reaches the bottom. The chopper is
pushed laterally and posterior.
Repositioning of the chopper and lateral separation: The chopper is repositioned in the depths of
the cracked nucleus. Lateral separating movement extends the crack antero-posteriorly.
Repositioning of the chopper at the floor of the trench with lateral separation extends the crack
until the bottom and severs the leathery fibres of the posterior plate, that hold the nucleus halves
together.
The two-hemi sections are produced in a gradual step-by-step fashion by repeated lateral
movements of the chopper at different sites all along the bottom of the trench/crater, while the
phacoprobe still holds the nucleus steady at 6 O'clock. Each nucleus half is rotated to lie
horizontally across the inferior capsular bag. Similar chop in situ and lateral separating movements,
result in multiple small lens fragments in each hemi section.
In essence, the left hand remains in action throughout the procedure, while the right hand remains
steady. The division is done in-situ and in a very subtle manner without transmitting stress to the
capsular bag or the zonules. Likewise multiple fragments are produced all around.
The MULTI-LEVEL CHOP TECHNIQUE:
It is a modification of our above mentioned division technique “Step By Step Chop In Situ & Lateral
Separation” After the central crater is created, the nucleus is held stationery by achieving a vacuum
seal with the probe in more than one plane, from anterior to posterior. The fibres adjacent to the
probe are initially chopped followed by minimal separating movements in every plane. Alternating
between the in situ vacuum seal and lateral separation manoeuvres allow division to be extended
posteriorly. Multiple fragments can be created by repeating this technique in every 1-2 clock hours.
This technique minimizes the separation-induced stress to the capsular bag and zonules. It allows
complete anterio-posterior division of all nuclear fragments. This eliminates the possibility of
partially divided nuclear fragments remaining attached to a central posterior plate. Each divided
nuclear fragment is can be individually lifted from the bag to perform emulsification in the
posterior plane.
LARGE VERSUS SMALL FRAGMENTS :
The advantage of our chop technique is that it produces multiple small fragments. Compared to
large fragments, small fragments can be safely consumed in the central space at the posterior plane
with superior surgical control.
FRAGMENT REMOVAL :
With torsional ultrasound fragment removal is very effective. There is no repulsion of the fragment.
The tip acts as a pivot and the fragment is held close to the tip until it is emulsified. I call it
“carouselling”. With Ozil the cutting is very effective, and there is less energy and heat dissipation.
Energy and aspiration work in harmony because the lens substance is not pushed away. This implies
that the clinicians can use lower aspiration flow rates and lower bottle height.
The IP software combines the torsional and the longitudinal ultrasound to improve the followability
of the nuclear material during the stage of fragment removal.
THE STEP DOWN TECHNIQUE:
For surgeons who use longitudinal ultrasound, the step down technique is very useful. It is a
judicious combination of using appropriate parameters for an appropriate stage of surgery and
slow motion phacoemulsification to facilitate safe posterior plane emulsification. The parameters
are reduced proportionately to the exposure of the posterior capsule, i.e. more the exposure of the
posterior capsule, more the reduction in the parameters.
IN CONCLUSION:
The difficulties encountered in emulsifying these dense cataracts can be overcome if one endeavors
endlessly and performs posterior plane emulsification that can be executed by:
 Advocating the use of OZIL technology
 Making a central deep space
 Making multiple small fragments
 Breaking the occlusion gradually
 Applying step down technique
Further reading:

Singh R, Vasavada AR. Step-by-step chop in situ and separation of very dense cataracts. J
Cataract Refract Surg 1998; 24:156-159.

Vasavada AR, Desai J. Stop, chop, chop and stuff. J Cataract Refract Surg 1996; 96: 526-528

Vasavada AR, Raj S. Step down technique. J Cataract Refract Surg 2003; 29:1077-1079

Vasavada AR, Goyal D, Shastri L, et al. Corticocapsular adhesions and their effect during
cataract surgery. J Cataract Refract Surg 2003; 29:309-314.

Vasavada AR, Raj SM, Patel U, Vasavada V, Vasavada V. Comparison of torsional and
microburst longitudinal phacoemulsification: a prospective, randomized, masked clinical
trial. Ophthalmic Surg Lasers Imaging. 2010 Jan-Feb;41(1):109-14.