Quantifying Phacoemulsification Handpiece Repulsion as a Function of Tip Design: A Particle Image Velocimetry Study

Area of Science:

• Ophthalmology
• Fluid Dynamics
• Biomedical Engineering

Background:

• Phacoemulsification is a key cataract surgery technique.
• Tip design significantly impacts fluidics and surgical outcomes.
• Understanding fluid motion is crucial for efficient lens fragment removal.

Purpose of the Study:

• To compare fluid dynamics of straight, flared, and balanced phaco tips.
• To analyze fluid motion in orthogonal planes around the tip aperture.
• To infer how fluid shear forces affect cataract fragment attraction and repulsion.

Main Methods:

• Utilized Virtuoso and Centurion phaco handpieces with different tip designs.
• Tested longitudinal, torsional, and combined modes for the balanced tip.
• Employed Particle Image Velocimetry (PIV) in a fluid chamber with neutrally buoyant particles.

Main Results:

• Balanced tips generated significantly higher fluid velocities than straight and flared tips.
• Fluid velocity increased with stroke length and ultrasound power.
• Aspiration significantly increased fluid attraction towards all tested tips.

Conclusions:

• Straight tips in longitudinal mode produce lower fluid velocities compared to other designs and modes.
• Balanced and flared tips offer superior fluidic performance in cataract surgery.
• Fluid dynamics play a critical role in the efficiency of phacoemulsification.