Tubing enhances phaco

This is an improvement over the original low-compliance Intrepid tubing that was not ergonomically comfortable, according to Lisa B. Arbisser, MD.

"A stable chamber with minimal surge may provide additional safety," said Dr. Arbisser, in private practice in Bettendorf, IA, and an adjunct associate professor at the John A. Moran Eye Center, University of Utah, Salt Lake City. "Fluid management systems vary with different management approaches to decrease the surge in Abbott Medical Optics, Alcon, and Bausch + Lomb technology."

"With occlusion, aspiration flow stops and the vacuum builds to the pre-set level," Dr. Arbisser said. "As the tip clears, the flow then resumes, and the system returns to the original lower vacuum. The tubing constricts during occlusion and expands with clearance, which may result in a rush of fluid into the phaco tip and shallowing of the anterior chamber. The constriction and expansion of the tubing contributes to surge. The new tubing minimizes this effect."

There are a number of ways to ease surge, according to Dr. Arbisser, such as rapid replacement of fluid when the occlusion eases, change in the pump speed or the aspiration fluid rate at the time of occlusion, change in the vacuum rise time, increased aspiration resistance, and reinforcement of the tubing to prevent collapse of the tubing that adds to the vacuum.

She shared test data generated by Alcon that were obtained from an evaluation of standard tubing and then compared with enhanced tubing to determine the difference in the surge.

"The difference between the two tubing types is more significant at higher vacuum settings compared with lower vacuum settings," she said.

The bending force of the tubes also was tested by the manufacturer. The original low-compliance tubing was found to have a higher bending value while the new low-compliance tubing has a lower stiffness that approximates the standard tubing, Dr. Arbisser said.

This was accomplished, she explained, by reducing the diameter and selecting a better tuning durometer.