• Organic Retinal Prosthesis Restores Vision in Animal Study

    By Jean Shaw and Lynda Seminara and selected by Deepak P. Edward, MD

    Journal Highlights

    Nature Materials
    Published online March 6, 2017

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    Maya-Vetencourt et al. fabricated and validated a fully organic and biocom­patible retinal prosthesis designed for long-term subretinal implantation. They tested it with mice and found that the device enabled the mice to recover light sensitivity and visual acuity, with the benefits persisting up to 10 months following surgery.

    For this study, the researchers used Royal College of Surgeons (RCS) rats, which are a preferred animal model of retinitis pigmentosa. The prosthesis comprised a flexible and highly con­formable silk substrate covered with photoactive layers of conjugated poly­mers. As the prosthesis used no metal- or silicon-based electronics, and its sensitivity corresponded to irradiances that fell within daylight illumination levels, there was no need for a power supply or external cameras.

    Restoration of visual function was evaluated at several stages of disease progression, and recovery was observed with regard to both visual cortical responses and visually driven behavior. Those improvements were accompanied by an increase in the basal metabolic activity of the primary visual cortex.

    The researchers confirmed, via histochemical studies, that the improvements were not a secondary trophic effect of the implant. Instead, they conclud­ed, the light-stimulated conjugated polymers directly activate residual neuronal circuitries in the retina. They acknowledged that a full understanding of the prosthesis’ principle of operation remains uncertain, but they hypothe­sized that it depends on the photogene­ration of long-lived excited states in the polymer layer and the subsequent interaction of these states with the retinal environment.

    The original article can be found here.