Prospective study shows water jet phaco as effective as ultrasound for majority of cataracts

Barbara 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 outcomes.

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," he added.

"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
rcjc@aol.com

Richard Mackool
The Mackool Eye Institute and Laser Center, New York
mackooleye@aol.com

Robert P Lehmann MD,
Assistant Clinical Professor,
Baylor College of Medicine
rkl@1cc.net

Lisa Arbisser MD
Eye Surgeons Associates, Davenport, Iowa, US
drlisa@arbisser.com

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