June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Behavioral assessment of photovoltaic subretinal prosthesis in rats with retinal degeneration
Author Affiliations & Notes
  • Henri Lorach
    Hensen Experimental Physics Lab, Stanford University, Stanford, California, United States
  • Florian Lazslo
    Hensen Experimental Physics Lab, Stanford University, Stanford, California, United States
  • Elton Ho
    Hensen Experimental Physics Lab, Stanford University, Stanford, California, United States
  • Xin Lei
    Electrical Engineering, Stanford University, Stanford, California, United States
  • Ludwig Galambos
    Electrical Engineering, Stanford University, Stanford, California, United States
  • Theodore Kamins
    Electrical Engineering, Stanford University, Stanford, California, United States
  • James Harris
    Electrical Engineering, Stanford University, Stanford, California, United States
  • Daniel V Palanker
    Hensen Experimental Physics Lab, Stanford University, Stanford, California, United States
    Ophthalmology, Stanford University, Stanford, California, United States
  • Footnotes
    Commercial Relationships   Henri Lorach, Pixium Vision (C); Florian Lazslo, None; Elton Ho, None; Xin Lei, None; Ludwig Galambos, None; Theodore Kamins, Pixium Vision (C); James Harris, None; Daniel Palanker, Pixium Vision (C), Pixium Vision (P)
  • Footnotes
    Support  NIH Grant R01-EY-018608
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4202. doi:
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    • Get Citation

      Henri Lorach, Florian Lazslo, Elton Ho, Xin Lei, Ludwig Galambos, Theodore Kamins, James Harris, Daniel V Palanker; Behavioral assessment of photovoltaic subretinal prosthesis in rats with retinal degeneration. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4202.

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

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Abstract

Purpose : Assessment of prosthetic vision using behavioral responses in awake animals is a challenge for many prosthetic approaches. Here we take advantage of the wireless nature of photovoltaic stimulation and measure characteristics of prosthetic vision using behavioral responses in rats with retinal degeneration.

Methods : Pigmented rats (n=9) were implanted subretinally with photovoltaic arrays. Among them, 6 animals had global retinal degeneration (RCS rats) and 3 were Long Evans (LE) rats that developed local degeneration above the implant. Stimulation was performed with 4 LED panels surrounding the cage, emitting 880nm radiation. Animal behavior in response to stimulation was recorded on video and analyzed by the experimenter.

Results : Implanted RCS rats reacted to prosthetic stimulation by startling (freezing) response, similar to the fear response in conditioning paradigms. This response was absent in the age-matched non-implanted RCS as well as in implanted LE rats, indicating that it is mediated by the implant and that remaining natural vision in LE rats negates startling response. With this method, we found stimulation thresholds of 0.17mW/mm2 with 10 ms pulses at 2 Hz. To assess contrast sensitivity, we applied a continuous train of pulses at 20 Hz, and modulated the pulse duration within 2 seconds long segments. We found responses to both increase and decrease in light intensity, with Michelson contrast of 12%.

Conclusions : Behavioral studies in awake, freely moving animals enable quantitative assessment of prosthetic vision, and reveal higher contrast sensitivity than with VEP measurements, as well as the presence of not only ON but also OFF responses.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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