An Optimized Computational Model of Retinal Ganglion Cells and Electrical Stimulation with Varied Epiretinal Electrode

Epiretinal prosthesis is a promising approach to help the blind restore partial visual function and has achieved preliminarily clinical success. Computational modeling and simulation is an efficient way to systematically investigate the responses of retinal electrical stimulation theoretically. The objective of this study was to establish an optimized hybrid model to better reflect more realistic human retina, and therefore to achieve more accurate study of retinal ganglion cell (RGC) excitation characteristics under varied electrical stimulus. Multilayered finite-element models (FEM) of peri-central (C) and peripheral (P) macular area were constructed to calculate extracellular electric potential with varied electrode diameter and distance to the retina. Four types of midget ganglion cell with different morphologies were developed to estimate RGC responses under varied stimulations. Furthermore, a randomized distributed multiple RGC model was built based on realistic human retina statistics. The multi-RGC model was utilized to further study the RGC population response to electric stimulation with varied electrode parameters. These results would provide a theoretical basis for electrode design of epiretinal prosthesis.