Patent ID: 8423151
Filing Date: 2013-04-16
Classification: A61N

Abstract:
1. A method of stimulating retinal neural tissue comprising: providing a neural stimulator including a plurality of electrodes suitable to stimulate retinal neural tissue; providing a biphasic square wave pulse to each electrode; calculating capacitive impedance by a first derivative of the voltage across a stimulation pulse; testing the impedance of all electrodes by obtaining voltage measurements from all electrodes in response to said square wave pulses; recording changes of capacitive impedance over time derived from said voltage measurements; and determining lifting of electrodes based on changes of a capacitive component of said impedance by considering phase shifts in said changes of impedance over time; wherein the changes of the capacitive component are computed based on a phase difference derived from a difference between a resultant voltage waveform obtained from the voltage measurements and a baseline voltage waveform without phase shifts derived from said voltage measurements.