A comparative study on electrically evoked responses of retinal ganglion cells in distinct retinal areas by computational model

Epiretinal prostheses have been reported to restore partial visual function of patients suffering from retinal degenerative diseases. The design of stimulating electrode array of the epiretinal prosthesis is one of the pivotal factors to influence its performance and spatial resolution. Because the cell density distribution of retinal ganglion cells(RGCs) and retinal anatomic structure varied with the eccentricity, stimulating electrodes should be designed specifically at different retinal eccentricities to obtain optimal visual restoration performance. In this study, computational models of epiretinal electrical stimulations in varied retinal eccentricity with variant RGCs densities in the temporal of center macular and peripheral macular areas were constructed. The activation thresholds and amount of excited RGCs were investigated and compared in these two areas under electrical stimulation with different pulse parameters, electrode sizes and electrode-retina distances. These modeling approaches can be used to further study the activated characters of RGCs in response to extrinsic electrical stimulations in different retinal areas, and improve the performance of epiretinal prostheses by optimizing stimulation strategies and electrode design.