Evaluation of the capsular safety of a new hybrid phacoemulsification tip in a cadaver eye model

Abstract

Purpose: To evaluate the use of a new hybrid phacoemulsification tip made with a high strength polymer overmold designed to prevent posterior capsule rupture (PCR) compared with a metal tip.

Setting: John A. Moran Eye Center, University of Utah, USA.

Design: Experimental study.

Methods: This ex vivo crossover study compared a new phacoemulsification tip to a metal tip. After a preliminary experiment applying the tips to the posterior capsule with the bevel down, 10 phakic cadaver eyes were prepared using the Miyake-Apple technique, after which each tip was tested in a series. After lensectomy, the posterior capsule was subjected to direct contact from the tip with the bevel up. The vacuum limit was set to 150 mm Hg, and the aspiration flow rate to 30 cc/min, after which the torsional power was increased by increments of 5% up to a maximum amplitude of 60%. The primary endpoint was the torsional power required to produce PCR.

Results: Vacuum alone did not cause PCR with either tip. All tests showed that a higher torsional power was required for PCR with the hybrid tip. With the bevel directed upward, the hybrid tip required higher torsional power before PCR than the metal tip (55% ± 10.0% [SD] versus 15% ± 4.1%, respectively) (P value < .001). This indicates that there is a lower likelihood for PCR with the hybrid tip.

Conclusion: The hybrid tip used in this study can be an effective means of preventing surgical complications such as PCR. This tip would be useful for experienced surgeons as well as for those who are in training.