Safety assessment of semichronic suprachoroidal electrical stimulation to rabbit retina

Confirming safety of chronic electrical stimulation is of prime importance for the practical use of visual prostheses. Here we applied electrical stimulation to eyes of freely-moving rabbits eight hour per day for one month. Examinations including fundus photo, optical coherence tomography (OCT), electrically evoked potentials (EEPs) were performed before and after one-month stimulation to detect tissue damage. No adverse effect caused by electrical stimulation was observed in electrophysiological and histological evaluation. We also found that there was no sign of morphological and electrochemical degradation of stimulating electrodes.