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A Methodological Protocol and Considerations for Transcranial Ultrasonic Stimulation in Exploratory Clinical Human Studies

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Optimum on-time duty cycle for micropulse technology.

Kevin R Kirk¹, Cecinio Ronquillo¹, Jason D Jensen¹

¹From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

Journal of Cataract and Refractive Surgery

|August 20, 2014

Summary

The optimal on-time for efficient phacoemulsification using micropulsed ultrasound (US) is 6 milliseconds. Shorter on-times reduce efficiency, while longer on-times increase lens fragment chatter.

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Area of Science:

Ophthalmology
Surgical Technology
Biomedical Engineering

Background:

Phacoemulsification is a key step in cataract surgery.
Optimizing ultrasound parameters is crucial for efficient lens removal.
Micropulsed ultrasound offers potential advantages in controlling energy delivery.

Purpose of the Study:

To determine the most efficient on-time setting for micropulsed ultrasound in removing lens fragments.
To evaluate the impact of varying on-times on phacoemulsification efficiency and chatter.

Main Methods:

An experimental study using porcine lens nuclei.
Lens fragments were subjected to micropulsed ultrasound with varying on-times (2-10 ms) and a constant off-time (10 ms).
Efficiency (time to removal) and chatter (fragment repulsion) were measured.

Main Results:

The highest efficiency was observed at a 6 ms on-time.
On-times shorter than 6 ms significantly decreased efficiency (R2=.82, P=.04).
On-times of 9-10 ms resulted in significantly more chatter events (P<.0001) compared to 2-8 ms, without improving efficiency.

Conclusions:

A 6 ms on-time setting for micropulsed ultrasound provides optimal efficiency for phacoemulsification.
Shorter on-times (2-5 ms) are less efficient.
Longer on-times (9-10 ms) increase chatter without enhancing efficiency, making 6 ms the recommended setting.