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Sonic wave a new alternative to ultrasound
Cataract fragmentation tool uses 3 to 4 orders of magnitude less energy.
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NEW YORK — A new low-energy cataract fragmentation tool provides benefits in safety and efficiency among other things, according to Stephen Bylsma, MD. He reported on STAAR Surgical’s Sonic Wave System at the Ninth Annual Ocular Surgery News Symposium here. “The reduced energy associated with the Sonic system is not associated with longer surgical times or new disassembly techniques,” said Dr. Bylsma. “The beauty of this,” he added, “is there is no change in technique, and there is really no loss of efficiency.”
The Sonic Wave System uses 200 to 1,000 times less energy than phacoemulsification ultrasound. Ultrasound is defined as frequencies above 20,000 Hz, and most conventional phaco units today use frequencies in the 40,000 Hz range. The Sonic Wave system uses energy between 40 and 400 Hz, or 3 to 4 orders of magnitude less energy. As a result, Dr. Bylsma reported, there is no turbulence, no cavitation and no thermal energy during surgery, regardless of lens density.
“What is amazing is that a system that can be so gentle with clear lenses can be so efficient at dense cataract removal,” said Dr. Bylsma. “Brunescent 4+ cataracts are safer to remove with the Sonic system because the lack of thermal energy renders a corneal or scleral burn an impossibility. Moreover, it is these hard-lens cases that bring the greatest risk to the endothelium,” he said.
The Wave system is capable of working in either sonic or ultrasound mode. “While the ultrasound profile is similar to conventional phaco units, the fluidics of the system is unsurpassed at promoting anterior chamber stability, even at extreme vacuum and aspiration levels,” said Dr. Bylsma. The fluidics technology involves coiled tubing that stabilizes the anterior chamber and promotes post-occlusion surge, he reported. “The coiled tubing uses a change in direction of fluid within the tube to create a barrier to occlusion rush. At low flow levels of up to 50 cc/min, this tubing acts like standard tubing. However, the instantaneous flow rate immediately following a break of occlusion can be in excess of 250 cc/min. Above 50 cc/min., the coils in the tubing create turbulent flow in the tubing, and this inhibits further increases to flow, so there is no occlusion rush, surge or anterior chamber dimpling,” Dr. Bylsma explained.
The coiled tubing enables surgeons to get back to large caliber tubing and tips, which, according to Dr. Bylsma, results in increased efficiency. “This is dependable, inexpensive, and it doesn’t rely on any kind of sophisticated microcircuitry,” he said. “Another [bonus] in terms of the fluidics of this particular system is that the pump never stops turning so the responsiveness is greatly increased. It’s like the difference between driving a high quality car and an economy car.”
No thermal burns
Dr. Bylsma said he routinely “chops” clear lenses with The Wave. “There is no cavitation around the nucleus, and so it embeds terrifically, and it will hold and remove clear lenses without breaking occlusion because there is no ultrasound and much lower energy,” he said. “There are no thermal burns because cooling is not needed. We don’t even need a sleeve. In the future, incisions will be on the order of 0.5 mm to 1 mm without a sleeve.”
A foot pedal allows a switch from the sonic to the ultrasonic mode. “With a simple flick of the switch of the foot pedal, one can change from the sonic directly to an ultrasonic. Some of the original machines had a blended sonic and ultrasonic system; above 70% sonic energy ultrasonic would kick in. “It turns out that that creates some corneal edema,” said Dr. Bylsma, “so the machines that are being made now, and all future machines, will have either pure sonic or pure ultrasonic with the foot pedal allowing the switch between.”
In terms of educational value, Dr. Bylsma says, The Wave has a great deal to offer. “It has a video component, and it can be put on the Internet. Live surgery can be monitored from a remote location anywhere in the world,” he said.
For Your Information:
- Stephen Bylsma, MD, can be reached at Shepard Eye Center, 1414 E. Main St, Santa Maria, CA 93454; (805) 925-2637; fax: (805) 347-0033. Dr. Bylsma has a proprietary interest in the products and devices mentioned in this article. He owns some of the Sonic Wave patents, and is a consultant to STAAR Surgical.
- STAAR Surgical can be reached at 1911 Walker Ave., Monrovia, CA 91016; (818) 303-7902; fax: (818) 358-9187.