Abstract
Purpose: The purpose of this work was to develop a model to predict and compare laser-trabecular meshwork interactions during laser trabeculoplasty with three different lasers. Methods: A qualitative multilayer optical-thermal model of the trabecular meshwork was developed. The model was used to estimate the penetration depth and heat diffusion volume during laser trabeculoplasty with a continuous wave argon laser (ALT), a Q-switched frequency-doubled Nd:YAG laser (SLT), and a flashlamp-pumped near-infrared alexandrite or titanium sapphire laser emitting microsecond pulses (μs-IRLT). Results: The model predicts that both SLT and μs-IRLT produce selective heating of pigmented trabecular meshwork cells with negligible heat diffusion to surrounding structures and with a deeper penetration at the IR wavelength. A preliminary quantitative analysis indicates that selective targeting of spherical pigments is achieved as long as the pulse duration remains less than approximately 1μs. Conclusion: The qualitative model indicates that infrared laser trabeculoplasty with microsecond pulses can produce selective targeting of pigemented trabecular meshwork cells with a deeper penetration than SLT.
