Modeling of the laser linear thermal effects on the anterior and posterior layers of the human eye with and without thermoregulation.

Abstract

This study presents a numerical model investigating the thermal effects of laser exposure on the cornea and retina of the human eye, with a focus on the role of blood flow in thermoregulation. Both the anterior and posterior segments of the eye are analysed to provide guidance on whether to account for blood flow in simulations of laser-based eye surgeries. Argon Fluoride (ArF), Holmium:Yttrium-Aluminum-Garnet (Ho:YAG), Neodymium-Doped:Yttrium-Aluminum-Garnet (Nd:YAG), and Ruby lasers are applied to a three-dimensional eye model. The Pennes' bio-heat transfer equation is solved using the Finite Element Method (FEM) to assess temperature distributions and penetration depths, ensuring that target tissues remain within safe temperature limits. The simulation results show maximum temperatures of 259°C, 89.2°C, 136°C, and 67.4°C for ArF, Ho:YAG, Nd:YAG, and Ruby lasers, respectively. Additionally, the explicit method is employed to model the pupil axis and further investigate blood flow's impact on thermoregulation. The inclusion of blood flow results in lower temperatures across all laser conditions, demonstrating its crucial role in regulating excess heat, particularly in the retina, which has a denser blood vessel network compared to the avascular cornea. These findings emphasise the importance of incorporating blood flow in thermal simulations to improve the accuracy of predictions and ensure safer outcomes in laser-based eye surgeries. This study employs a comprehensive approach combining precise modelling, simulations, and numerical analysis to investigate the effects of lasers on both the cornea and retina. This offers a wide understanding of laser-tissue interactions and helps in optimizing treatment parameters for both types of ocular tissues. Finally, a comparison table is presented alongside existing studies to highlight the achieved temperatures and penetration depths in laser-tissue interactions.