Retinal dystrophies and age-related macular degeneration related to photoreceptor degeneration can cause blindness. In blind patients, although the electrical activation of the residual retinal circuit can provide useful artificial visual perception, the resolutions of current retinal prostheses have been limited either by large electrodes or small numbers of pixels. Here, we report the evaluation, in three awake non-human primates, of a previously reported near-infrared-light-sensitive photovoltaic subretinal prosthesis. We show that multi-pixel stimulation of the prosthesis within radiation-safety limits enabled eye tracking in the animals, that they responded to the stimulations in the direction of the implant with repeated saccades, and that the implant-induced responses were present two years after device implantation. Our findings pave the way for the clinical evaluation of a 378-electrode prosthesis in patients affected by dry atrophic age-related macular degeneration.
We report the development of an all-organic active pixel sensor (APS) composed of a poly3-hexylethiophene (P3HT) and phenyl-C61-butryic acid methyl ester (PCBM) organic photodiode (OPD) connected to two organic field effect transistors and present here a study of its electro-optical characteristics. The OPD showed dark currents of 17.5 nA cm −2 with an external quantum efficiency of 30%. Our organic transistors feature UV-curable ion gels to obtain a high-capacitance dielectric with a combination of high electronic mobility, up to 4 cm 2 V −1 s −1 , and extremely low operating voltage, below 2 V. The APS configuration gives an in-pixel amplification of the photodetector response, with the gain reaching 40 under a 41 mW cm −2 illumination.
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