Thermal inertia associated with ultrapulse technology in phacoemulsification

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Acoustics

Background:

• Phacoemulsification uses ultrasound to remove cataracts.
• Traditional ultrasound pulses can cause thermal damage to eye tissues.
• Minimizing heat propagation is essential for patient safety during ophthalmic surgery.

Purpose of the Study:

• To compare thermal inertia between very short (5-6 milliseconds) and traditional (50 milliseconds) ultrasound pulses.
• To investigate the impact of pulse duration on heat propagation in biological tissues.
• To determine if shorter ultrasound pulses reduce thermal effects during ophthalmic procedures.

Main Methods:

• Thermal testing was conducted in balanced salt solution (BSS) and human eye-bank eyes.
• Net temperature increase was measured using a phacoemulsification unit with different pulse durations (6 ms vs. 50 ms).
• Experiments were replicated in BSS and eye tissues to compare heat generation ratios.

Main Results:

• Six-millisecond ultrasound pulses resulted in 10.9% less heat generation in limbal tissue compared to 50-millisecond pulses (P = .0002).
• The reduction in heat generation with shorter pulses was consistent when comparing BSS and eye tissue results.
• This indicates a significant difference in thermal inertia based on ultrasound pulse duration.

Conclusions:

• Very short ultrasound pulses (5-6 milliseconds) propagate less thermal energy in ocular tissues than traditional 50-millisecond pulses.
• Shorter pulse durations may offer a safer alternative by minimizing heat-related complications in ophthalmic surgery.
• Further research can explore the clinical implications of reduced thermal energy in cataract surgery.