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

https://doi.org/10.1016/j.jcrs.2019.06.016Get rights and content

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.

Section snippets

Cadaver Eye Preparation

Twenty human cadaver eyes were obtained through collaboration with eye banks nationwide. The eyes, which were obtained from donors who had previously consented for organ donation, were harvested within 72 hours after the patients were deceased. The eyes arrived at the Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, USA, in moistened chambers, and they were prepared using the Miyake-Apple technique to allow for visualization of the posterior portion of the

Cadaver Eyes

The study comprised 20 human cadaver eyes that had been enucleated from the donors within 1 day of the patient's passing and were subsequently received by the Intermountain Ocular Research Center. The eyes subsequently underwent surgery at a mean of 2.5 days ± 0.8 (SD) after the patient's passing, with a range of 1 to 4 days. The mean age of the donors was 65.2 ± 15.0 years (range 51 to 81 years). Six of the donors were men, and three were women. One of the pairs of eyes received did not

Discussion

The data show there is a significant statistical difference between the groups, with the hybrid tip having a larger torsional power before causing PCR. In other words, the hybrid tip is less likely to cause PCR than the metal tip. The data collected from Experiment 2 show the most statistical significance and seem to be most conclusive. This experiment also most closely mimics the surgical technique that is likely to be employed in routine phacoemulsification, with the phaco tip oriented bevel

First author:

Caleb Shumway, MD, MBA

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

First author:

Caleb Shumway, MD, MBA

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

Supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York, USA, to the Department of Ophthalmology and Visual Sciences, University of Utah, and by a research grant from Alcon Laboratories, Inc., Fort Worth, Texas, USA.

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