Direct stimulation of optic nerve by electrodes implanted in optic disc of rabbit eyes

Abstract

The visual cortex can be activated by direct microelectrical stimulation of the optic nerve. The acute implantation of the wire microelectrodes into the optic disc by a transvitreal approach is feasible and results in only limited damage to the optic nerve.

Intraorbital optic nerve stimulation with penetrating electrodes: in vivo electrophysiology study in rabbits

“…These results suggest that optic nerve stimulation with penetrating electrodes can have much lower thresholds than that with surface electrodes. Compared with our data, the lower threshold of stimulating the optic nerve head reported by Fang et al [9] was probably due to the difference in the material and the exposed surface of stimulating electrodes. In their study, platinum wire was used as stimulating electrode, and the exposed surface of stimulating electrode was about 0.4× 10 −4 cm 2 larger than ours.…”

“…Histological analysis of transverse sections of the optic nerve of the eyes implanted with electrodes showed that the stimulating electrode was penetrated into the optic nerve, and the depth of the implantation was about 0.5 mm. Their results demonstrated that cortical responses could be elicited by this approach [8,9,38]. However, the optimal stimulus parameters to activate the optic nerve have not been investigated systematically.…”

“…Compared with VEPs, the shortened latency of P1 of EEPs is presumably due to the fact that the direct electrical stimulation of axons of ganglion cells spares the time that is needed for processing visual inputs by retinal cells. With single biphasic rectangular pulse stimulation, the charge density threshold in our study was 21.36±5.64 μC/cm 2 , while 6.21 μC/cm 2 was obtained in rabbits by stimulating the optic nerve head [9] and 80 μC/cm 2 was obtained in a blind patient (calculated at pulse duration of 404.7 μs) with surface cuff electrodes around the optic nerve [5]. These results suggest that optic nerve stimulation with penetrating electrodes can have much lower thresholds than that with surface electrodes.…”

Properties of electrically evoked potentials activated by optic nerve stimulation with penetrating electrodes of different modes in rabbits

“…ON visual prosthesis has been considered a potential approach to restore vision for the blind with retinal degeneration diseases [32][33][34][35][36][37][38][39][40][41]. Our group proposed a visual prosthesis based on intraorbital ON stimulation with penetrating electrodes, which has been demonstrated to evoke visual cortical responses with lower current thresholds and improved spatial resolution compared with surface cuff electrode ON stimulation [36,37,41].…”

“…Visual prostheses have proved to be a promising way to restore partial functional vision for patients with RP. Three major types of visual prostheses have been investigated according to the stimulation locations: cortical prostheses [3][4][5][6][7], retinal prostheses using epi-and subretinal stimulation , and optic nerve (ON) prostheses [31][32][33][34][35][36][37][38][39][40][41]. The retinal prosthesis is the most developed type among the three, and the Argus II epiretinal prosthesis has been approved by the European CE and the US FDA for clinical use [23].…”