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Patterned optical activation of retinal ganglion cells

Final Report Summary - OPTISTIM (Patterned optical activation of retinal ganglion cells)

The main goal of the OPTISTIM research project was the development of a novel approach towards vision restoration in individuals suffering from degenerative diseases of the outer retina. In diseases such as Retinitis Pigmentosa (RP) and Age-related Macular Degeneration (AMD), which are among the most common causes of blindness, photoreceptors degenerate while the inner retinal neurons and in particular the retinal ganglion cells (RGCs) and their optic nerve projections are largely maintained functional; artificial stimulation of these relatively well-preserved nerve cells is one of the primary approaches currently being pursued towards vision restoration for the blind. Current approaches towards artificial stimulation of retinal ganglion cells rely primarily on microelectrode array implants.
The OPTISTIM project pursued a direct photo-stimulation approach to this challenge, which potentially offers fundamental advantages because it can be non-contact and can leverage display devices for high-resolution patterned spatial-temporal control of light patterns. Neural photo-stimulation, primarily using optogenetics is a technological alternative with significant potential benefits over electrical stimulation: it is non-contact, enables higher spatial resolution and can be genetically targeted and used for inhibition of activity as well as excitation. The core components of an optical retinal interface (Fig. 1) are a method for optically exciting the neurons, and a suitable micro-display. In addition, the system requires components for capturing the visual input and for translating it into cellular stimulation patterns. Project OPTISTIM focused on the development of new types of projectors, primarily for high-rate digital-holographic pattern photo-stimulation. The project’s results demonstrate that using this technology we can accurately control the activity of individual retinal ganglion cells both in vitro and in vivo. To achieve this, we developed unique technical tools, for example, new tools for imaging and stimulating the retina in vivo at a cellular resolution (Fig. 2).
Finally, with colleagues at the Technion and at Insightech, we are exploring another new concept: the stimulation of retinal and other neurons using holographic ultrasonic patterns. We have published promising early in-vivo support for the viability of this approach which could potentially lead to a completely non-invasive retinal stimulation interface (Fig. 3).