Thermal heating of a retinal prosthesis: thermal model and in-vitro study

In order to develop retinal implants with a large number of electrodes, it is necessary to ensure that they do not cause damage to the neural tissue by the heat that the electrical circuits generate. Knowledge about the threshold of the amount of power that induces thermal damage will greatly assist in development of power budgets for implants, which has a significant effect upon the design of implant circuitry. In this study, we developed and tested in-vitro equipment that can dissipate thermal energy in current prosthesis implantation sites while simultaneously measuring and recording temperature distributions at multiple locations along the retinal tissue. A finite element thermal model of the feline eye was also created and validated by the in-vitro tests allowing for a much larger spectrum of thermal influences to be evaluated without the additional cost of animal sacrifice.