Effective stimulation parameters affecting the stimulating threshold for epi-retinal prostheses

Epi-retinal prostheses have achieved remarkable results on restoring vision in patients through electrical stimulation. However, such devices still need further development to achieve better vision quality to help patients with their daily lives. The main hurdles lie in the facts that the understanding of the neural response to electrical stimulation is limited, and many factors affect the stimulation effect in complex ways. This paper mainly summarizes the influences of electrode parameters and stimulation currents on the stimulating thresholds from animal and human studies, as well as from mathematical modeling. Results show that work towards better understanding of the retinal electrical stimulation requires further efforts and mathematical modeling is a potential approach to achieve that.