Comparison of a torsional and a standard tip with a monitored forced infusion phacoemulsification system

Abstract

Purpose: To compare the relative efficiency and chatter of the 30-degree 0.9 mm Kelman tip (standard tip) and Ozil Intrepid Balanced tip (torsional tip) with identical optimum settings.

Setting: John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA.

Design: Experimental study.

Methods: Porcine nuclei were fixed in formalin and cut into 2.0 mm cubes. Lens cubes were phacoemulsified with standard and torsional tips at 60% and 100% torsional amplitude with 0%, 25%, 50%, 75%, and 100% longitudinal power with monitored forced infusion. Experiments were performed at a constant vacuum, aspiration rate, and intraocular pressure.

Results: Linear regression showed increased efficiency with up to 75% longitudinal power at 60% torsional amplitude for both tips (P = .046 standard; P = .0093 torsional). Longitudinal did not significantly increase efficiency at 100% torsional power for either tip. Torsional tips were on average 29% more efficient than standard tips throughout the range tested (P < .0001), and 100% torsional power was on average 45% more efficient than 60% torsional power (P = .0028). Chatter was minimal except at 100% longitudinal power, which was greater than at 75% longitudinal power (P < .0001). At 100% longitudinal power, torsional tips had more chatter than standard tips (at 60% torsional, P < .0001; at 100% torsional, P = .0022).

Conclusions: Increasing up to 75% longitudinal power increased the efficiency at 60% torsional for standard and torsional tips. Torsional tips were more efficient than standard tips. Chatter was generally minimal. Torsional tips showed more chatter than standard tips at 100% longitudinal power.

Financial disclosure: None of the authors has a financial or proprietary interest in any material or method mentioned.