An Average Amplitude Regulation Scheme for Ambient Illuminance Adaptation in Retinal Prosthesis

Abstract

This letter proposes an 8-channel retinal prosthesis stimulator with an average amplitude regulation (AAR) scheme to enable illuminance adaptation in retinal prosthesis to improve visual acuity in patients. The AAR scheme facilitates effective light adaptation by maintaining a consistent average stimulation current with global feedback. This method supports both subretinal and epi-retinal prostheses by regulating stimulus current levels rather than photodiode sensitivity. This approach eliminates the need for complex metal line connections, reducing pixel size. Experimental results demonstrate the AAR scheme’s effectiveness in maintaining appropriate stimulation levels, with the capability to return to the original average stimulation current within 260 ms after sudden changes in brightness, while achieving stimulation current mismatch less than 3.03%.