March 2007

 

CATARACT/ IOL

 

Are there advantages with AquaLase?


by Matt Young EyeWorld Contributing Editor

 

 

 

Surgeons debate when AquaLase works best— and when it might not

When it was originally developed, AquaLase (Alcon, Fort Worth, Texas) was thought by some surgeons to provide a potentially marketable alternative to ultrasound phacoemulsification, Mark Packer, M.D., clinical associate professor, ophthalmology, Casecy Eye Institute, Oregon Health and Science University, Portland, said recently. Before the advent of “cool” phacoemulsification, researchers were looking for a way to perform bimanual microincision cataract surgery without using a too large an irrigation sleeve, and AquaLase seemed to provide one solution because it was simply warm pulses of BSS sterile solution that didn’t require a sleeve, he said. But AquaLase wasn’t necessarily needed for that, as technologies like WhiteStar (Advanced Medical Optics, AMO, Santa Ana, Calif.) soon became available, providing phacoemulsification energy that kept cool through millisecond-range delivery of power with variable duty cycles, Dr. Packer said. Ironically, not all studies have even suggested AquaLase—despite its avoidance of mechanical energy—is indeed safer than ultrasound. Some recent studies have suggested it can actually cause more endothelial damage than ultrasound. Other recent studies suggest, however, that endothelial cell loss is similar with both AquaLase and ultrasound. Regardless, some cataract surgeons suggest AquaLase technology lacks advantages over ultrasound and therefore isn’t the most useful tool in the surgical armamentarium.

New take on AquaLase and endothelial cells

At the 2006 ASCRS•ASOA Symposium & Congress, San Francisco, Nada Jiraskova, Ph.D., chief of ophthalmology, Charles University Hospital, Hradec Kralove, Czech Republic, presented a study in which AquaLase was performed in the right eye of patients and NeoSoniX (Alcon) in the left eye. In the AquaLase eyes, endothelial cells were reduced from 2,744 pre-op to 2,368 by one month post-op. In the left NeoSoniX eyes, the loss was less—2,730 endothelial cells reduced to 2,495 at one month post-op. According to OSN, Oleg Fechin, M.D., IRTC Eye Microsurgery Ekaterinburg Center, Russia, also reported at the XXIV Congress of the ESCRS in London in 2006, that in 108 eyes, endothelial cell loss did not significantly differ from grades 1 to 3. However, eyes with grade 4 cataracts had a significantly greater endothelial cell loss with AquaLase, averaging 14% compared to 11% for standard phaco.

But a new study—supported by Alcon—suggests endothelial cell loss is similar in a fluid-based phacoemulsification system versus ultrasound. This study did not analyze grade 4 cataracts, but generally ophthalmologists agree that AquaLase is better suited for softer lenses. A total of 46 eyes of 23 patients with up to 3+ bilateral cataract were included in that study. The first eye was randomized to either the fluid-based system or conventional ultrasound, and the fellow eye received the alternate system. Post-op, no significant differences were found among the groups. In the fluid-based system, 6.3% of endothelial cells were lost and in the ultrasound group, 7.9% were lost. “Visual acuity, pachymetry, and endothelial cell loss after cataract extraction and intraocular lens implantation using a fluid-based system is similar to conventional ultrasound,” lead author Helga P. Sandoval, M.D., Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston, wrote in her study. A. Tsorbatzoglou, M.D., Department of Ophthalmology, University of Debrecen, Hungary, also found in his March 2006 Eye study that endothelial changes were similar in both AquaLase and ultrasound as well. In 60 eyes of 60 patients evenly divided into both surgical modalities, endothelial cell loss was 6.5 to 8.4% in the fluid-based group and 6.5 to 11.7% in the ultrasound group. “The fluid-based method proved to be as safe as conventional ultrasound in cataract surgery,” Dr. Tsorbatzoglou wrote.

Further thoughts on AquaLase

Most surgeons would say that up to 2+ grade nuclei, AquaLase is safe and effective, Dr. Packer said. “Beyond that, AquaLase takes a long time, especially if you have dense material,” he said. Further, he said, regarding the argument that with very soft cataracts, AquaLase might be safer or lead to a quicker improvement in vision: “I don’t buy that either. We’re not even using ultrasound in soft cataracts. With any machines, I could do a 1 to 2+ cataract with zero power. I just don’t use any ultrasound. It’s just the fluidics. Why do I need a jet of warm water to go into the eye?”

In soft cataracts, Dr. Packer said he essentially just uses hydrodissection and hydrodilineation to loosen up the material and then extracts it with a high vacuum and flow rate. “I don’t feel like having AquaLase adds much” to a surgeon’s tool kit, he said. Calvin Roberts, M.D., clinical professor of ophthalmology, Weill Medical College of Cornell University, N.Y., also suggested that endothelial cell loss has more to do with fluidics than with the phacoemulsification modality. “Corneal endothelial cells are very sensitive to fluid turbulence within the anterior chamber,” Dr. Roberts said. “Think of endothelial cells as really graceful fine leaves hanging off of a branch and the turbulence of the fluid is like a strong wind. The more wind you have the more leaves you’re going to lose. If AquaLase is going to have the same fluidics, then you would expect to have similar amounts of endothelial cell loss.”

Dr. Roberts said that currently, he’s a big fan of another Alcon technology, the OZil handpiece, for emulsification purposes. He said that works wonders with soft cataracts. “What I’ve found is that since I switched from standard phaco to the OZil, really small lenses get emulsified and aspirated with the OZil with very low amounts of energy—almost none,” Dr. Roberts said. “The flare tip on the OZil has a larger port to aspirate material through so you don’t have to break up so much. If I had a soft nucleus and I had a choice of two technologies—AquaLase or OZil, I would take the OZil.”

Editors’ note: Dr. Packer is a consultant for AMO (Santa Ana, Calif.), Bausch & Lomb (Rochester, N.Y.), and receives travel support and honoraria from Alcon (Fort Worth, Texas). Dr. Roberts has no financial interests related to his comments.

Contact Information

Jiraskova: jirasnad@fnhk.cz

Packer: 541-687-2110, mpacker@finemd.com

Roberts: 212-734-7788, robertsmd1@aol.com

Sandoval: 843-792-2305, sandoval@musc.edu

Tsorbatzoglou: +36 5241 5816, alex@jaguar.unideb.hu

Are there advantages with AquaLase? Are there advantages with AquaLase?
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