1. A method of optimizing an electrode tissue interface comprising: implanting at least one electrode in the vicinity of visual neural tissue; electrically stimulating the visual neural tissue through the at least one electrode, wherein a stimulation signal to each electrode comprises one or more pulses, and wherein frequency of each of the one or more pulses is within a first frequency range; measuring impedance of the electrode tissue interface to obtain an impedance measurement; adjusting the frequency of at least one pulse in the one or more pulses to be within a second frequency range based on said impedance measurement, wherein the second frequency range is narrower than the first frequency range; and altering location of said at least one electrode based on said impedance measurement and said second frequency range.