Photovoltaic arrays implanted under the degenerated retina can convert light into pulsed electric current to stimulate the second-order retinal neurons for restoration of sight. Images captured by a camera are projected onto the retina from augmented-reality glasses using pulsed near-infrared light. Patients with such implants demonstrated consistent form perception with a letter acuity closely matching the 100um pixel size. Using current steering and 3-dimensional electrodes, pixels as small as 20um can stimulate the inner retina, providing grating acuity matching the pixel pitch, up to the natural resolution limit of 28um in rats. Optimization of these implants for human retina is in progress.
Sight can be restored in patients who lost photoreceptors due to atrophic AMD by substituting them with a photovoltaic array. Subretinal pixels convert pulsed NIR light projected from augmented-reality glasses into electric current, stimulating the nearby inner retinal neurons. Patients with such implants can simultaneously use their residual peripheral sight and central prosthetic vision, and its acuity closely matches the 100um pixel size of the implant. We present two approaches to selective neural stimulation with pixel sizes down to 20um – optically configurable current steering and 3-dimensional honeycomb-shaped electrodes, both providing prosthetic acuity matching the natural resolution in rats.
Photovoltaic retinal prosthesis is designed to restore sight in patients who lost central vision due to atrophic AMD. Subretinal pixels convert pulsed NIR light projected from augmented-reality glasses into electric current, stimulating the nearby inner retinal neurons. In patients with geographic atrophy, such prosthetic central vision coexists with natural peripheral sight, and its acuity closely matches the 100um pixel pitch of the implant. We present a progress toward 20um pixels based on honeycomb configuration of the stimulating arrays with return electrodes elevated on vertical walls, designed to leverage retinal migration for decoupling the stimulation threshold from pixel size.
Macular degeneration leads to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well preserved. Photovoltaic subretinal prosthesis converts light into pulsed electric current, stimulating the nearby inner retinal neurons. Clinical trial with such implants having 100um pixels, as well as preclinical measurements with 75 and 55um pixels, confirm that spatial resolution of prosthetic vision can reach the pixel pitch. For a broad acceptance of this technology, visual acuity should exceed 20/100, which requires pixels smaller than 25um. I will present 3-dimensional electro-neural interface scalable down to cellular-scale pixel size.
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