Thermal Tissue Modeling of the Ciliary Body With Continuous Wave Transscleral Cyclophotocoagulation and Transscleral...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Physics

Background:

• Continuous wave transscleral cyclophotocoagulation (CW-TSCPC) is a glaucoma treatment, but its thermal effects on the ciliary body (CB) can lead to complications.
• MicroPulse transscleral laser therapy (TLT) offers a potentially safer alternative by using pulsed laser energy, but its thermal dynamics require detailed evaluation.

Purpose of the Study:

• To compare the thermal dynamics of CW-TSCPC and MicroPulse TLT in a simulated ciliary body using computer modeling.
• To analyze key thermal parameters including peak temperature, exposure duration, and thermal spread for both techniques.

Main Methods:

• A five-layer homogeneous slab model of the ciliary body was developed using Monte Carlo methods.
• CW-TSCPC was modeled using parameters for classic and slow coagulation techniques with the G-Probe.
• MicroPulse TLT was modeled using the MicroPulse P3 probe, simulating thermal effects during sweep path applications.

Main Results:

• CW-TSCPC elevated CB peak temperatures above 100°C for up to 2.2 seconds and above 60°C for up to 5.5 seconds, with a 2 mm thermal spread.
• MicroPulse TLT elevated CB temperatures above 60°C for 0.15–1.1 seconds, with a thermal spread of 0.6–1.2 mm, and did not exceed 100°C.
• MicroPulse TLT exhibited lower peak temperatures, shorter exposure durations, and less thermal spread compared to CW-TSCPC.

Conclusions:

• MicroPulse TLT demonstrates more favorable thermal dynamics than CW-TSCPC, characterized by lower temperatures and reduced thermal spread.
• The findings suggest MicroPulse TLT minimizes the risk of permanent coagulative tissue necrosis, supporting its enhanced safety profile.
• Understanding these thermal dynamics is crucial for optimizing treatment parameters and maximizing clinical outcomes for both modalities.