May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
A Visual Prosthesis Based on Intraorbital Optic Nerve Stimulation With Penetrating Electrodes: In vivo Electrophysiology Study in Rabbits
Author Affiliations & Notes
  • L. Li
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • M. Sun
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • P. Cao
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • X. Chai
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • K. Wu
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • X. Sui
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • Q. Ren
    Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
  • Footnotes
    Commercial Relationships  L. Li, None; M. Sun, None; P. Cao, None; X. Chai, None; K. Wu, None; X. Sui, None; Q. Ren, None.
  • Footnotes
    Support  National Basic Research Program of China (973 Program, 2005CB724302)
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 3037. doi:https://doi.org/
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    • Get Citation

      L. Li, M. Sun, P. Cao, X. Chai, K. Wu, X. Sui, Q. Ren; A Visual Prosthesis Based on Intraorbital Optic Nerve Stimulation With Penetrating Electrodes: In vivo Electrophysiology Study in Rabbits. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3037. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : The purpose of this study is to assess the effects of varying stimulus parameters on the electrically evoked potentials (EEP) elicited by intraorbital optic nerve stimulation with penetrating electrodes.

Methods: : Teflon-coated tungsten wire electrodes were inserted into the intraorbital optic nerve of rabbits. Charge-balanced biphasic current stimuli were applied to the optic nerve via the inserted electrodes. EEP were recorded by epidural electrodes over the visual cortex. The threshold of both current and charge density were determined. The effects of varying stimulus pulse amplitude, duration, frequency and waveform on EEP were studied. Visually evoked potentials (VEP) were recorded as a control. Histological analysis of the optic nerve was performed after the experiments.

Results: : EEP were successfully elicited by intraorbital optic nerve stimulation with penetrating electrodes. The threshold of current and charge density for eliciting EEP was 32.08 ± 8.44 µA and 20.99 ± 5.52 µC/cm2, respectively. The P1 amplitude of EEP increased and the latency decreased with increasing current pulse amplitude and duration. The P1 amplitude saturated as the charge was greater than 60 nC. As the stimulus charge was fixed, the P1 amplitude decreased and the latency increased with increment of the pulse duration. The P1 amplitude decreased monotonically when the current frequency varied from 1 to 10 Hz. Among the five different charge-balanced biphasic stimulating waveforms, the symmetrical cathode-first biphasic pulse elicited the largest cortical responses. Histological analysis showed mild damage to the optic nerve tissue induced by the electrical stimulation.

Conclusions: : Our study shows that visual prosthesis based on intraorbital optic nerve stimulation with penetrating electrodes requires relatively low thresholds,and narrow symmetrical cathodic-first biphasic pulse with low frequency is more efficient to stimulate the optic nerve directly.

Keywords: electrophysiology: non-clinical • neuro-ophthalmology: optic nerve • retina 
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