What are your favorite phacoemulsification tools and how do you
make the most of them? Five experts provided advice on the latest
devices, settings and approaches for state-of-the-art surgery.
Here’s what they had to say.
Mark Packer,
MD
The Sovereign (AMO) pioneered the
concept of micropulse phaco, the application of
short millisecond-range emissions of ultrasonic vibration followed
by a variable length pause. Initially regarded as a means to
improved followability, this technology also enabled recent
investigations into thermal effects at the corneal wound site. The
Infinity (Alcon) and the Millennium (Bausch & Lomb) both now
incorporate micropulse technology, enabling variable duty cycles and
vast reductions in ultrasound energy utilization.
The Sonic Wave (Staar) introduced sonic frequency
phaco several years ago, enabling cooler tip temperatures
and microincision techniques. While slower for extraction of denser
nuclei, the Wave achieves outstanding chamber stability despite high
vacuum levels with coiled Super Vac tubing and the Cruise
Control (Staar), an inline flow restrictor capable of
diminishing surge flow to safe levels. While the Cruise
Control can be applied to any phaco machine, it does necessitate a
change in parameters.
Occlusion-mode phaco was first made available on
the Diplomax (AMO) and similar technology is now available on most
state-of-the-art machines. This programming allows the pump to
sense when vacuum rise signals the development of occlusion. It also
permits the surgeon to control speed. Small changes in these
settings can mean dramatic differences in surgical efficiency, as
material comes more quickly to the tip and a firm hold develops more
rapidly, allowing quick and successful chopping and extraction of
material.
For bimanual microphaco, I use the 20-gauge Duet System (Micro
Surgical Technologies), using the front-end irrigating choppers. I
prefer the open-ended irrigator for refractive lens exchange and
soft nuclei, the canoe paddle-like vertical chopper designed by
Hiroshi Tsuneoka for 2 to 3 + nuclei, and a chopper I designed,
nicknamed the Packer penguin, for dense cataracts. I use a
30-degree straight 20-gauge phaco needle. The capsulorhexis
forceps designed by Micro Surgical Technologies permit
reproducible initiation of the tear with a central pinch and
exquisite control throughout completion. A small
(4-millimeter-diameter), centered capsulorhexis is essential for
optimal function of the Crystalens IOL (Eyeonics), and microincision
surgery facilitates chamber stability during capsulorhexis
construction by disallowing egress of viscoelastic.
A clear corneal microincision should be tight enough to prevent
significant outflow, trapezoidal to allow adequate instrument
mobility, and capacious enough to prevent tissue damage and loss of
self-sealability. A variety of diamond knives now
meet these criteria.
Dr. Packer is clinical assistant professor of ophthalmology
at Oregon Health & Science University and is in private practice
in Eugene, Ore. He receives travel and research funds from Alcon and
AMO.
Douglas D. Koch,
MD
All of the leading manufacturers have
introduced excellent innovations in power modulation and
fluidics. My experience has been primarily with the Alcon
Infinity, and I find that the capabilities for power modulation have
greatly enhanced the ease and elegance of surgery. I have
particularly enjoyed using high pulse rates (40 to
55 pulses/ second) with variable on/off times for both sculpting and
chopping. I have also found linear burst to be
advantageous in the initial phases of the chop procedure.
My standard approach is stop-and-chop. For sculpting the groove,
I use 40 pulses per second with 80 percent “on” time. I begin
chopping using 40-ms linear burst, and I remove segments using 50
pulses per second with 40 percent “on” time. I use the Neosonix with
a 0 threshold for sculpting and a 20 percent threshold for the
second and third phases of nuclear removal. With a high pulse rate,
one can reduce chatter through a combination of low energy and high
pulse frequency. I recognize that these settings are unique to the
Alcon device, but similar principles can be applied to other
machines that offer sophisticated power modulations.
Dr. Koch is professor of ophthalmology at Baylor College,
Houston. He is a consultant for B&L, Alcon and Pfizer.
Samuel Masket,
MD
I operate in two locations. In one, I
use the Sovereign with WhiteStar; in the other, I use the Infinity.
Clearly, the devices differ in their styles and software, and they
bring advantages over their predecessors. Most important, they both
have the safety of surge-protection software, which
I find a very important factor. Occasionally, I operate with a
Legacy unit (Alcon). Under those circumstances, I find it beneficial
to use the Cruise Control device, because the Legacy does not have a
surge protector. The Cruise Control maintains
chamber stability by preventing postocclusion surge. It also
collects the cataract material, which I offer to patients. They
often enjoy seeing what has been removed.
Irrespective of the emulsification machine, as long as the eye is
protected against surge, I prefer to work with the
phacoemulsification tip with the bevel facing toward the lens.
Typically, that would be bevel down for initiating phaco-chop
maneuvers. The key to success with chop methods is to achieve and
maintain occlusion of the tip. In this way, the vacuum will build
and hold the lens material firmly in order to enable chopping
maneuvers, irrespective of whether one is using a vertical or
horizontal chopping method.
Dr. Masket is clinical professor of ophthalmology at the
University of California, Los Angeles, and is in private practice in
Century City, Calif. He is a consultant to AMO and a member of the
Alcon speakers’ alliance.
David F. Chang,
MD
Compared with five years ago, we
have so many more weapons in our arsenal. Let’s take one of the most
intimidating cases—the mature, brunescent cataract with weak
zonules.¹ We have capsular dye, improved viscoelastics,
Mackool capsule retractors and capsular tension
rings. On the machine side, we have
hyperpulse to reduce chatter and heat, and
Cruise Control to eliminate surge in the face of a
lax, trampolining capsule. Using a double-ended chopper, I combine
vertical phaco chop to fracture through the tough posterior plate,
with horizontal chop to subdivide the large fragments into
“bite-sized” chips to reduce chatter and particle turbulence at the
phaco tip.
Phaco surgeons must master an interdependent confluence of
instrumentation, technology and technique. We must dynamically
adjust our machine parameters according to our technique and to
individual characteristics of the eye and the nucleus. I have long
thought that combining video teaching with an illustrated textbook
would be the best instructional approach for such an objective. I
finally collaborated with the faculty from my Academy phaco chop
course to produce such an integrated approach.²
Dr. Chang is clinical professor of ophthalmology at the
University of California, San Francsico, and is in private practice
in Los Altos, Calif. He is a consultant for AMO, a consultant and
U.S. medical monitor for Visiogen and has received educational
travel support from Alcon, but has no financial interest in any
instruments or devices mentioned.
Randall J. Olson,
MD
I continue to find
ultrapulse technology valuable for three reasons.
It improves followability (particularly with very hard cataracts) in
that the very short pulses don’t bounce the particle off in the same
way that other ultrasound approaches do. There is a decrease in the
rate of overall energy expenditure, so that my ultrasound time is
further diminished. This is potentially important in protecting the
cornea, especially with extremely hard cataracts.
Directly related to the duty cycle (the amount of time ultrasound
is on), the decreased energy used results in less wound heating, and
I feel this represents a decreased risk of wound burn. The latest
6.0 software of White Star, which starts out at a very long duty
cycle and increases only as necessary, has even further diminished
my ultrasound time, and further improved followability.
I have transitioned from horizontal to vertical chop, which
allows me to use greater mechanical effort without having to go
outside the pupil and has improved the speed, efficiency and, I
think, safety of my nucleus removal. Horizontal chop, however, is a
nice back-up tool in difficult cases.
Fortunately, ultrapulse technology requires no learning curve.
One can use any nucleus removal approach. I would start with 5 or 6
ms on and 12 to 20 ms off as a good starting point. The rest of the
parameters should be whatever you currently use.
As far as phaco chop goes, take a good course, such as the one
that Dr. Chang has at the Academy. Then use the approach as
outlined: first, chop quadrants, then chop hemi-nuclei, then move to
the full approach. With a little experience, it is easy to see the
advantages, particularly in tough cases.
Dr. Olson is chairman of ophthalmology at the University of
Utah, Salt Lake City. He is a consultant for AMO and heads the
Medical Advisory Board for Calhoun Vision.
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1
See “Ophthalmic Pearls” in the March EyeNet at www.eyenetmagazine.org/archives.
2
Chang, D. F. Phaco Chop: Mastering Techniques, Optimizing
Technology and Avoiding Complications (Thorofare, N. J.: Slack,
2004).