Can electric current steering be used to control perception of a retinal prosthesis patient

We consider a form of current steering to elicit desired perceptions in users of a retinal prosthesis. While it is common to use a single, remote return electrode to balance electrical stimulation, advances in chip design and electrical switching have enabled more flexibility in stimulation paradigms. We have created a finite-element model of a retina and a ten electrode prosthesis in COMSOL. Different configurations of stimulating and return electrodes are considered and employed to predict possible user perception. We investigate charge balance on electrodes in our varying geometries and consider the impact of inhomogeneous resistance between electrodes and the tissue.