Development and implant of the photovoltaic artificial retina in the pig with photoreceptor degeneration: towards the human Phase-1 experimentation

One of the most prevalent causes of severe bilateral blindness is the progressive degeneration of photoreceptors typical of Retinitis pigmentosa (RP). Various therapeutic approaches, including drug treatment, gene therapy or stem cell transplantation, have been unsuccessful in the most advanced forms of RP. This encouraged many groups to attempt a restoration of visual function using electrical stimulation of the spared retinal network. We created a novel artificial visual prosthesis consisting of an organic semiconductor interfaced with retinal neurons. In this system, the organic layer substitutes the damaged photoreceptors by absorbing light and eliciting neuronal activation. This device has many advantages with respect to the silicon-based ones currently on clinical testing: no power supply and heat production, high biocompatibility, intimate connection to living tissues, high spatial and temporal resolution. We demonstrated that the device is able to rescue light sensitivity in explanted blind degenerate retinas, as well as, after in vivo implantation in RCS rats, a model of Retinitis pigmentosa. We will extend the results obtained in the RCS rat to the pig with photoreceptor degeneration, an experimental animal with an eye closely similar to the human eye. We will engineer the prosthesis and the surgical procedure to adapt it to the human eye and test its ability to rescue visual acuity as well as its long-term tolerability and functioning. This will allow to exploit the promising results obtained in the dystrophic rat in view of the final transfer of the prosthesis to selected human patients.