AbstractsBiology & Animal Science

The quality of visual perception with epiretinal electric stimulation strongly depends on the configuration of electrode arrays. Such arrays at the surface of the retina should excite only cells within a local area, but in practice, they exhibit some cross-talk, possibly leading to a smearing of focal activation of the retina. In this study, a passive model of extracellular voltage distribution arising from epiretinal stimulation is solved using the method of finite differences, in order to explore the voltage and current distributions of a hexagonal electrode array configuration. Results of this study suggest that the hexagonal electrode arrangement is effective in providing targeted focal activation of retinal tissue. Cross-talk between hexagonal clusters may be minimized by stimulus paradigms which utilize six return (or guard) electrodes around each stimulus electrode.