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Paul-Henri PREVOT, Sami Dalouz, Kevin Blaize, Elisabeth Dubus, Georges A Goetz, Daniel V Palanker, Martin Deterre, Guillaume Buc, José Sahel, Serge A Picaud; Ex vivo characterization of photovoltaic subretinal implants using non-human blind primate retinas. Invest. Ophthalmol. Vis. Sci. 2016;57(12):603.
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© ARVO (1962-2015); The Authors (2016-present)
Photovoltaic subretinal implants have been shown to elicit retinal ganglion cell (RGC) action potentials by electrically stimulating the inner nuclear layer in blind rodent models. We here tested their efficacy to activate retinal neurons in an ex vivo model of blind non-human primates.
Photoreceptors were removed from the non-human primate retina by vibratome sectioning. This ex vivo blind retina was kept in culture for several days. RGCs were recorded on a multielectrode array (MEA) while concurrently activating the implant with pulses of near-infrared light (NIR, 880-915nm) of varying intensities and pulse widths. Information processing was suppressed in the retina by synaptic blockers (LAP4, CNQX).
Histological retinal sections clearly demonstrated the selective loss of photoreceptors in our blind model. When this retinal tissue was recorded with the MEA, RGCs responded to full-field stimulation as well as stimulation from a single 140µm-wide pixel. Under single pixel stimulations, RGCs responded to one or two pixels indicating a very high resolution with limited flash durations (1 to 10 ms) and light levels below radiation safety limits. Application of synaptic blockers showed that activation of bipolar cells was part of the RGC action potentials, indicative of a subretinal stimulation.
These results demonstrate that our photovoltaic subretinal implants can stimulate indirectly primate retinal ganglion cells in a degenerated retinal model. They pave the way for future clinical trials to assess visual restoration in blind patients using these new modular miniaturized photovoltaic implants, potentially providing an elegant solution for blind patients.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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