Computational Modeling of Electromagnetic and Thermal Effects for a Dual-Unit Retinal Prosthesis: Inductive Telemetry, Temperature Increase, and Current Densities in the Retina

Abstract

Recent advances in electromagnetic and thermal modeling of a dual-unit retinal prosthesis are presented. The focus is on the latest computational methods to quantify electrical and thermal deposition in the human tissue with the ultimate goal of addressing safety concerns and optimizing the overall performance of the system. A Partial Inductance Method (PIM) is used for the computation of the electrical coupling parameters of the radiating and receiving telemetry coils. Results for the inductive coil coupling are presented and different coil geometries are compared. Further, a finite difference method for the solution of a bio-heat equation is used to compute the temperature increase caused by the implanted electronics and the electromagnetic absorption due to the external power and data telemetry link. Temperature increases due to the implanted microchip, coils, and stimulating electrode array are shown. Finally, our computational approach based on a multi-resolution impedance method is used for the computation current spread in the human tissue. Results are presented showing variations of current spread in the retina and eye due to different electrode array geometries and placement configurations.