Transretinal Electrical Stimulation by Intrascleral Multichannel Electrode in Rabbit Eyes

Abstract

Abstract: : Purpose: Several approaches for placing a retinal prosthesis using transretinal electrical stimulation, such as via subretina and epiretina, have been previously proposed. We will report if the transretinal stimulation from the intrascleral pocket can elicit an electrical evoked potential (EEP) in rabbits. Methods: A new multichannel active electrode array (polyimide plate, Au- electrode) was developed and used for this study. After creating a scleral pocket (2 x 6 mm) and placing an anchoring suture, the array was inserted into the scleral pocket and positioned at the intrascleral space. A stainless wire was implanted into the vitreous space as a reference electrode. For electrical stimulation, a monophasic pulse was used (parameters: electric current, duration, and polarity). When stimulating the retina with transretinal current, EEP was investigated. Results: : We developed a new, safe approach for placing an electrode array in the intrascleral space. When the electrical stimulation was applied, the EEP could be recorded with an epidural electrode. The threshold was 0.2 mA (0.5 msec). The EEP consisted of 3 components , which were similar to the visual evoked potentials (VEP). Conclusions: Transretinal electrical stimulation from the intrascleral space could elicit EEP, suggesting that this approach may be safe and useful for a retinal prosthesis system.

Keywords: retinal development • retinal pigment epithelium • animal model