Electrophysiological evaluation of a chronically implanted electrode for suprachoroidal transretinal stimulation in rabbit eyes

  • Kentaro NishidaEmail author
  • Hirokazu Sakaguchi
  • Motohiro Kamei
  • Toru Saito
  • Takashi Fujikado
  • Kohji Nishida
Original Article Others


In this study, we aimed to determine the electrophysiological efficacy, safety, and electrical stability of a chronically implanted electrode for suprachoroidal transretinal stimulation (STS) in rabbit eyes. A platinum microelectrode was implanted into the scleral pocket of rabbit eyes (n = 5) and followed-up for 6 months. To evaluate the electrophysiological efficacy, electrically evoked potentials (EEPs) were measured every month after implantation. To evaluate safety, fundus examinations, fluorescein angiograms, electroretinograms (ERGs), and visually evoked potentials (VEPs) were measured before and every month after the implantation. At the end of the experiment, histological examination of retinal tissue beneath the site of the electrode was performed. To evaluate electrical stability, the resistance of the circuit was measured every month after implantation. EEPs could be elicited from the STS electrodes at all testing times. The mean threshold current to evoke EEPs was 186.4 ± 47.0 µA at 6 months after implantation. There was no significant change in the threshold over the follow-up period. The resistance of the circuit was significantly increased at 1 months after implantation, with no further increase at 6 months. There was no statistically significant change in the relative amplitudes and implicit times of a- and b-waves of ERGs and VEPs. No intraocular infection, inflammation, or vitreoretinal proliferation was observed in any eye. Histological examination revealed no retinal damage beneath the electrode. We conclude that chronically implanted electrodes for STS appear to be effective, safe, and electrically stable.


Suprachoroidal transretinal stimulation Electrically evoked potentials Electroretinograms Visually evoked potentials Resistance 


Compliance with ethical standards

Conflict of interest

Ke. Nishida, None; H. Sakaguchi, None; M. Kamei, None; T. Saito, NIDEK Co., Ltd, Employment; T. Fujikado, None、Ko. Nishida, None.


  1. 1.
    Dobelle WH. Artificial vision for the blind by connecting a television camera to the visual cortex. ASAIO J. 2000;46:3–9.CrossRefGoogle Scholar
  2. 2.
    Pezaris JS, Reid RC. Demonstration of artificial visual percepts generated through thalamic microstimulation. Proc Natl Acad Sci USA. 2007;104:7670–5.CrossRefGoogle Scholar
  3. 3.
    Da Cruz L, Dorn JD, Humayun MS, et al. Five-year safety and performance results from the argus II retinal prosthesis system clinical trial. Ophthalmology. 2016;123:2248–54.CrossRefGoogle Scholar
  4. 4.
    Chow AY, Chow VY, Packo KH, et al. The artificial silicon retina microchip for the treatment of vision loss from retinitis pigmentosa. Arch Ophthalmol. 2004;122:460–9.CrossRefGoogle Scholar
  5. 5.
    Stingl K, Bartz-Schmidt KU, Besch D, et al. Subretinal visual implant alpha IMS–clinical trial interim report. Vision Res. 2015;111:149–60.CrossRefGoogle Scholar
  6. 6.
    Rizzo JF 3rd, Wyatt J, Loewenstein J, et al. Methods and perceptual thresholds for short-term electrical stimulation of human retina with microelectrode arrays. Invest Ophthalmol Vis Sci. 2003;44:5355–61.CrossRefGoogle Scholar
  7. 7.
    Brelen ME, Vince V, Gerard B, et al. Measurement of evoked potentials after electrical stimulation of the human optic nerve. Invest Ophthalmol Vis Sci. 2015;51:5351–5.CrossRefGoogle Scholar
  8. 8.
    Nishida K, Kamei M, Kondo M, et al. Efficacy of suprachoroidal-transretinal stimulation in a rabbit model of retinal degeneration. Invest Ophthalmol Vis Sci. 2010;51:2263–8,2.CrossRefGoogle Scholar
  9. 9.
    Fujikado T, Kamei M, Sakaguchi H, et al. One-year outcome of 49-channel suprachoroidal-transretinal stimulation prosthesis in patients with advanced retinitis pigmentosa. Invest Ophthalmol Vis Sci. 2016;57:6147–57.CrossRefGoogle Scholar
  10. 10.
    Sakaguchi H, Kamei M, Fujikado T, et al. Artificial vision by direct optic nerve electrode (AV-DONE) implantation in a blind patient with retinitis pigmentosa. J Artif Organs. 2009;12:206–9.CrossRefGoogle Scholar
  11. 11.
    Nishida K, Sakaguchi H, Kamei M, et al. Visual sensation by electrical stimulation using a new direct optic nerve electrode device. Brain Stimul. 2015;8:678–81,2015.CrossRefGoogle Scholar
  12. 12.
    Stronks HC, Barry MP, Dagnelie G. Electrically elicited visual evoked potentials in Argus II retinal implant wearers. Invest Ophthalmol Vis Sci. 2013;54:3891–901.CrossRefGoogle Scholar
  13. 13.
    Ward MP, Rajdev P, Ellison C, et al. Toward a comparison of microelectrodes for acute and chronic recordings. Brain Res;. 2009;1282:183–200.CrossRefGoogle Scholar
  14. 14.
    Roitbak T, Sykova E. Diffusion barriers evoked in the rat cortex by reactive astrogliosis. Glia. 1999;28:40–8.CrossRefGoogle Scholar
  15. 15.
    Turner JN, Shain W, Szarowski DH, et al. Cerebral astrocyte response to micromachined silicon implants. Exp Neurol;. 1999;156:33–49.CrossRefGoogle Scholar
  16. 16.
    Rennaker RL, Street S, Ruyle AM, et al. A comparison of chronic multi-channel cortical implantation techniques: manual versus mechanical insertion. J Neurosci Methods. 2005;142:169–76.CrossRefGoogle Scholar
  17. 17.
    Holecko MM II, Williams JC, Massia SP. Visualization of the intact interface between neural tissue and implanted microelectrode arrays. J Neural Eng. 2005;2:97–10235.CrossRefGoogle Scholar
  18. 18.
    Nayagam DA, Williams RA, Allen PJ, et al. Chronic electrical stimulation with a suprachoroidal retinal prosthesis: a preclinical safety and efficacy study. PLoS One;. 2014;9:e97182.CrossRefGoogle Scholar
  19. 19.
    Prince JH, Diesem DC, Eglitis I, et al. The rabbit. In: Anatomy and Histology of the Eye and Orbit in Domestic Animals. Springfield: Charles C Thomas; 1960. pp. 260–93.Google Scholar
  20. 20.
    Olsen TW, Aaberg SY, Geroski DH, et al. Human sclera: thickness and surface area. Am J Ophthalmol. 1998;125:237–41.CrossRefGoogle Scholar
  21. 21.
    Tsui I. Scleral buckle removal: indications and outcomes. Surv Ophthalmol. 2012;57:253–63.CrossRefGoogle Scholar
  22. 22.
    Zhou JA, Woo SJ, Park SI, et al. A suprachoroidal electrical retinal stimulator design for long-term animal experiments and in vivo assessment of its feasibility and biocompatibility in rabbits. J Biomed Biotechnol. 2008. Google Scholar

Copyright information

© The Japanese Society for Artificial Organs 2019

Authors and Affiliations

  1. 1.Department of OphthalmologyOsaka University Graduate School of MedicineSuitaJapan
  2. 2.Department of OphthalmologyAichi Medical UniversityNagakuteJapan
  3. 3.NIDEK Co., LtdGamagoriJapan

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