Determination of the temperature increase in the human eye due to electromagnetic fields

Purpose - The purpose of this paper is to present a numerical analysis of the specific absorption rate (SAR) and temperature increase in a three dimensional (3D) anatomical human eye model exposed to electromagnetic (EM) fields at 1.9, 2.4 and 5.1 GHz, in particular devices such as tablets, smart phones, etc., which are based on Wi-Fi and 4G technology. Design/methodology/approach - A new 3D model of the human eye composed of nine different tissues with a high resolution of 0.5 mm is presented, including a precise definition of the cornea and lens and also distinguishing the cornea from the aqueous humor and the sclera from the retina and choroid. The EM problem is solved from the Maxwell's equations which gives the electric field and in turn enables the calculation of the SAR in any part of the eye model. The thermal problem is solved from the bioheat (Pennes') equation taking the SAR as an input of the power dissipated by the EM field. In both cases the finite difference time domain method is employed. Findings - A plane-wave field located 30 cm away from the eye is considered as the source for the far-field EM exposure. The results for maximum SAR indicate that the smallest value is 0.06 W/kg in the lens for 1.9 GHz whereas the highest value encountered is 0.43 W/kg in the vitreous humor for 5.1 GHz. In the worst case, the maximum SAR in the lens is 0.28 W/kg for 5.1 GHz. In all cases, the SAR values are within the limits defined by international standards. In terms of maximum temperature, the highest value found is 0.01 C in the cornea, aqueous humor and lens for 5.1 GHz. Originality/value - The work presents a thorough numerical calculation of the temperature increase in the human eye induced by devices that are based on Wi-Fi and 4G technology operating at 1.9-5.1 GHz.