Specific Absorption Rate and Temperature Increase in Human Eye Subjected to Electromagnetic Fields at 900 MHz

Abstract

Human eye is one of the most sensitive parts of the entire human body when exposed to electromagnetic fields. These electromagnetic fields interact with the human eye and may lead to cause a variety of ocular effects from high intensity radiation. However, the resulting thermo-physiologic response of the human eye to electromagnetic fields is not well understood. In order to gain insight into the phenomena occurring within the human eye with temperature distribution induced by electromagnetic fields, a detailed knowledge of absorbed power distribution as well as temperature distribution is necessary. This study presents a numerical analysis of specific absorption rate (SAR) and heat transfer in the heterogeneous human eye model exposed to electromagnetic fields. In the heterogeneous human eye model, the effect of power density on specific absorption rate and temperature distribution within the human eye is systematically investigated. In particular, the results calculated from a developed heat transfer model, considered natural convection and porous media theory, are compared with the results obtained from a conventional heat transfer model (based on conduction heat transfer). In all cases, the temperatures obtained from the developed heat transfer model have a lower temperature gradient than that of the conventional heat transfer model. The specific absorption rate and the temperature distribution in various parts of the human eye during exposure to electromagnetic fields at 900 MHz, obtained by numerical solution of electromagnetic wave propagation and heat transfer equation, are also presented. The results show that the developed heat transfer model, which is the more accurate way to determine the temperature increase in the human eye due to electromagnetic energy absorption from electromagnetic field exposure.

Temperature elevation produced by miniature implantable antennas for Intracranial Pressure Monitoring

“…Most of the studies investigating heat transfer in biological tissues use original Pennes bio-heat equation [5]. In many studies, the coupled model of Maxwell's equations and bio-heat equation has been used [6][7][8]. The majority of the published work about RF human exposure, though, have not studied temperature distributions produced inside human tissues, thus, the related analysis of the underlying phenomena is partially incomplete.…”

Heat Transfer Analysis of the Human Eye During Exposure to Sauna Therapy

“…Our research group has numerically investigated the temperature increase in human tissue subjected to EM fields in regard to many problems [37][38][39][40][41][42][43][44][45]. Wessapan et al [38,39] utilized a 2D finite-element method (FEM) to determine the specific absorption rate (SAR) and temperature increase in the human body exposed to leaking EM waves.…”

“…Keangin et al [42][43][44] carried out a numerical simulation of liver cancer treatment using a complete mathematical model that considered the coupled model of EM wave propagation, heat transfer, and mechanical deformation in the biological tissue in the couple's way (two or more equations are being solved simultaneously). Wessapan et al [45][46][47] investigated the SAR and temperature distribution in the eye during exposure to EM waves using the porous media theory.…”

“…Advanced models of the eye based on porous media and natural convection theory have been used in various heat transfer problems [29][30][31][32][33][34][35][36][45][46][47]. However, most studies have mainly focused on the effects of convective boundary conditions and have not considered the effects of radiation from high-temperature sources in the simulations.…”

Effects of aqueous humor hydrodynamics on human eye heat transfer under external heat sources

“…The same investigation was later extended by Karampatzakis and Samaras [18] using a three-dimensional model of the human eye for exposure to 40-100 GHz mm wave radiation. In a series of studies, Wessapan and Rattanadecho [19][20][21][22] investigated the elevation in the ocular temperature when exposed to electromagnetic (EM) waves using a two-dimensional model. A similar study was carried out to look at the ocular temperature distribution during sauna therapy [23] .…”