Prospective study shows water jet
phaco as effective as ultrasound for majority of cataracts
Boughton in San Francisco
THE Aqualase liquefaction device of the Alcon Infiniti system is
useful for treating soft to medium cataracts while reducing the
risk of complications, according to several speakers at the annual
ASCRS Symposium on Cataract, IOL and Refractive Surgery.
Initial results from a prospective study comparing traditional ultrasound
to Aqualase indicate that nuclear removal time with the two technologies
is similar, while cortex removal time with the Aqualase is superior
to ultrasound, said Robert Cionni MD of the Cincinnati Eye Institute.
In the study, 75 eyes with grade 2-3 cataracts were treated with
either ultrasound or Aqualase liquefaction. The nuclear removal
time with Aqualase was slightly higher at 3.4 minutes versus 2.1
minutes. The cortex removal time was also shorter at 0.57 minutes
versus 0.68 minutes.
"The nuclear removal time and cortex removal time will diminish
as we get more experience with Aqualase. The reason for the improved
cortex removal time is that as micropulses disrupt the nucleus,
they also get into the cortex and fluff it, making it more amenable
to aspiration," he noted.
With the Aqualase, micropulses of saline fluid are heated and reflected
off the lumen into the cataract to melt it for aspiration. From
the soft polymer tip, the warmed BSS fluid fans out into the nuclear
material. The Aqualase produces little turbulence in the eye and
has good flow. For most cataract surgeries done with the Aqualase,
a pulse strength of 10-15% is sufficient.
Dr Cionni commented that, unlike the Phacolase system, the 'feel'
of the Aqualase is very similar to ultrasound.
Robert Lehmann MD added that, in his experience, Aqualase liquefaction
produces an extremely clear cornea on the day following surgery.
"There is no significant endothelial cell loss and it is very
gentle on the posterior capsule. It eliminates thermal loss and
cell loss and you get clearer, cleaner capsules," he said.
Prior to clinical use, tests of the Aqualase showed that there is
no rise in temperature in the eye in position one with irrigation
even with continuous pulsing. Tests with pressure transducers showed
that intraocular pressure did not rise enough to produce adverse
Dr Cionni added that there are fewer incisional burns and ruptured
capsules with Aqualase than with ultrasound because there is no
movement in the tip, and thus no friction is built up.
Tests on cadaver eyes have shown that at a vacuum setting of 50,
Aqualase produces no tears even at 90% power. At 100% power, however,
at the same vacuum setting, tears are possible. By contrast, ultrasound
can produce tears at a setting as slow as 20% power.
The technology allows excellent "in-the-bag" liquefaction
of nuclear material and also improves cortical clean-up, thus reducing
the risk of PCO, Dr Cionni said.
"It is well shown that if the anterior capsule overlays the
optic of the lens, you reduce PCO. And with the optic covered by
the anterior capsule, you know where the lens is going to end up
in the eye-another advantage for 'in the bag' liquefaction,"
"The Aqualase liquefaction handpiece may prove to be the gentlest
manner in which to remove lens material, with the exception of high
vacuum. It removes nuclear cataracts of up to grade 2 with reasonable
efficiency, and because it is exceedingly difficult to rupture the
posterior capsule with this technology, it may have applications
in polishing the capsule, removing lens equatorial cells as well
as in resident training," commented Richard J. Mackool MD.
The limitations of the Aqualase, however, include the fact that
it is useful only for softer grade nuclei (2-3) and is less effective
with older patients with denser nuclei.
"Aqualase really doesn't apply to dense 'Coca-Cola' nuclei.
With the current Infiniti and the technology we have now, dense
black nuclei are emulsified effectively," he added.
Dr Lehmann noted that the learning curve with Aqualase has less
risk than with ultrasound. He noted that Aqualase can be used even
in difficult cases, such as one in which there is poor hydrodissection,
in which the nucleus is bound within the capsular bag:
"With the Aqualase, I'm extremely comfortable in peeling that
nucleus out of the bag - more comfortable than with ultrasound."
"Aqualase seems to be very promising. It has the potential
to prevent PCO, though with Aqualase you cannot do every cataract.
It's another wonderful modality in our hands," agreed Lisa
Arbisser, MD, past president of the American College of Eye Surgeons.
Robert Cionni MD
Cincinnati Eye Institute, Cincinnati, Ohio, US
The Mackool Eye Institute and Laser Center, New York
Robert P Lehmann MD,
Assistant Clinical Professor,
Baylor College of Medicine
Lisa Arbisser MD
Eye Surgeons Associates, Davenport, Iowa, US