engleski

Analysis of the Temperature Distribution to the Human Eye Exposed to Laser Radiation

The objective of this thesis is to study the time dependent temperature field of the human eye exposed to laser radiation. The mathematical model is based on the space-time dependent Pennes' bio-heat transfer equation. The numerical approach for the calculation of intraocular temperature distribution is based on the Time Domain Finite Element Method (TD-FEM) involving the weak Galerkin-Bubnov formulation of the problem. The effects of laser wavelength and power to the temperature distribution in the human eye are studied. The study contemplates both steady and time dependent numerical solutions for different laser sources such as Ruby, Nd:YAG, Ho:YAG, ArF, and Nd:YLF. The obtained results compare very well to the results available in the existing literature and to the results obtained with other numerical approaches based on the Finite Difference Time Domain (FDTD) as well as to the Boundary Element Method (BEM). A sensitivity analysis contemplating the effect of ambient temperature, the convective heat transfer coefficient, and the laser beam diameter in the cornea is presented. In addition, this work compiles a collection of absorption coefficients corresponding to various tissues of the human eye. This data was obtained after an exhaustive revision of the currently available literature.

human eye model; temperature distribution; finite element method; laser-tissue interaction; laser modeling

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