Frequencies and tip-strokes of commonly used phaco machines vary

This experimental study found that three of the most popular phaco machines - the Infiniti Ozil, the Whitestar Signature and the Stellaris - had different working frequencies and stroke dynamics.

The authors used a micro camera and a micropulsed strobe-light system to measure frequency and a microscopic video apparatus to measure tip displacement as vectorial movement at different phaco powers.

In the longitudinal mode, the Infiniti system ran at 43.0 kHz, while the Whitestar Signature and Stellaris systems worked at approximately 29.0 kHz. In torsional mode, the Infiniti Ozil machine had a frequency of approximately 31.6 kHz, and the Whitestar Signature with the Ellips FX handpiece ran at approximately 38.0 kHz.

The longitudinal stroke of the three machines at different phaco powers was significantly different. The Stellaris machine had the highest stroke extent (139 μm). The lateral movement of the Infiniti Ozil and Whitestar Signature machines differed significantly. No movement on the y-axis was observed for the Infiniti Ozil machine in torsional mode. The elliptical path of the Ellips FX handpiece had different x and y components at different phaco powers.

The authors conclude that a deep knowledge of each machine allows a customized parameter setting according to clinical needs and surgeon preferences. More clinical studies are needed to evaluate and compare the in vivo effects and advantages of different approaches to phacoemulsification.