Software upgrade improves phaco efficiency, safety

April 1, 2005

Variable WhiteStar, the new Version 6 software upgrade for Sovereign with WhiteStar (AMO), affords enhanced intraoperative micropulse control and allows surgeons to titrate the ultrasound energy precisely according to the density of each lens fragment. This advanced technology allows for increased intraoperative control while minimizing energy utilization and further increasing procedural efficiency and safety, agree cataract surgeons using the new software.

WhiteStar itself is advanced power modulation technology based on computer-controlled delivery of micropulses of ultrasound energy in very short on-off cycles. Its benefits include improved cutting ability and followability with decreased chatter for increased surgical efficiency. It also minimizes turbulence and heat generation to make phacoemulsification surgery safer.

Variable WhiteStar allows surgeons to program up to four individual micropulse duty cycles within the linear power function of foot pedal position three, providing them expanded access to all the variations of the duty cycle matrix within a single case. With the opportunity to change the duty cycle intraoperatively, the amount of "on" time and energy expended can be changed as needed to meet the demands of the individual case.

Roger F. Steinert, MD, agreed.

"The new software takes micropulse phaco to an even higher level, maximizing efficiency and minimizing undesirable wasted energy that translates into heat and turbulence," said Dr. Steinert, professor of ophthalmology, and vice chairman of clinical ophthalmology, University of California-Irvine.

"Once surgeons have tried the new software, they will realize that previous foot position three is like playing a one-string guitar. You can strum harder, but still only get one tone," Dr. Steinert added. "The new WhiteStar software is like playing a four-string guitar, and the music is very sweet."

Duty cycle settings When using the new software, Dr. Olson programs in CL (6 msec on, 24 msec off; equivalent to 20%) as the default low power setting and CC (6 msec on, 6 msec off; 50%) as the maximum power setting. [According to WhiteStar nomenclature, duty cycles are designated with two letters in the alphabet where each letter corresponds to 2 msec, the first represents the duration of the "on" cycle and the second is the duration of "off", e.g., CL is equivalent to a 20% duty cycle with 6 msec on, and 24 msec off.] Dr. Olson uses the CL mode during the majority of his cases, but he presses on the foot pedal as needed, increasing the duty cycle to CC rarely and for brief bursts only.

"I use a chopping technique with a second instrument to mash the nuclear material and just enough ultrasound energy for holding and to keep the case moving along," Dr. Olson explained. "However, with Variable WhiteStar, I depress the foot pedal when the need arises for a burst of extra energy."

Dr. Olson has analyzed energy used during cases performed with the new and previous WhiteStar software. Switching from conventional Sovereign surgery to WhiteStar reduced power usage by 50% to 60%. With the shift to the new WhiteStar software, energy utilization is down another 35% to 40%, he said.