A Preliminary Exploration on Dynamic Virtual Channel for Epiretinal Stimulation: A Modelling Study

Retinal prostheses aim to restore functional vison for the blind suffering from retinal degeneration diseases. The visual acuity recovered by a retinal prosthesis is often restricted by the limited electrode number and density. Virtual channel (VC) is a strategy for improving resolution without increasing number of physical electrodes. Some previous studies have investigated the characteristics of traditional stactic VC without considering the effects of time intervals when multiple VCs are involved. However, the actual performance of VCs will be largely influenced by the time intervals between time adjacent VCs. In this study, we analyzed the effect of time intervals between two consecutive VCs on the activation pattern of computational model of retinal ganglion cells (RGCs), which we define as the dynamic virtual channel (DVC) condition. We found that the activated RGC area is quite different at varied time intervals. In addition, the activated RGC area can be kept consistent after optimizing intervals between VC pairs. Our results indicate that performance of DVC can be well optimized by appropriate stimulating parameter selection.