Threshold of permanent cornea thermal damage due to incidental continuous wave CO2 laser irradiation

Abstract

Cornea thermal damage due to incidental continuous wave CO2 laser irradiation is studied numerically based on bio-heat equation. The interaction of laser with tissue leads to a rapid temperature increased in target and the nearby tissue. As the temperature of the eye surface reaches 44?C, a sensation of pain will cause aversion response of the reflex blink and/or shifting away from the source of pain. The aim of the work is to predict numerically the threshold limit of incidental laser power that causes damage to the anterior part of the cornea, which can be healed within 2-5 days as long as damage is not exceeding the outer part of the eye (epithelium). A finite element analysis is used to predict temperature distribution through the cornea where the necroses region can be obtained using thermal dose equation. The thermal dose that required for damaging the cornea is predicted from previously published experimental data on rhesus monkeys and used later as a limit for shrinkage to human cornea. The result of this work is compared by international standard of safety and a good nearby result is obtained which verified the result of this work.

Three-dimensional FTn finite volume solution of short-pulse laser propagation through heterogeneous medium

“…The study of short-pulse laser propagation through scattering and participating medium has received significant recent interest [1][2][3][4]. This technique is used in the processing of treatment of metallic materials [1], microstructures [2], laser surgery [3], and photodynamic therapy [4]. In addition, it can reduce the destruction adjacent healthy cells by its lower heat-affected zone [3,4].…”

“…This technique is used in the processing of treatment of metallic materials [1], microstructures [2], laser surgery [3], and photodynamic therapy [4]. In addition, it can reduce the destruction adjacent healthy cells by its lower heat-affected zone [3,4]. It is also applied to several high-precision medical treatments such as ophthalmology, neurosurgery, and corneal surgery [1][2][3][4].…”

“…In addition, it can reduce the destruction adjacent healthy cells by its lower heat-affected zone [3,4]. It is also applied to several high-precision medical treatments such as ophthalmology, neurosurgery, and corneal surgery [1][2][3][4].…”