Direct stimulation of the visual cortex is one potential way to partially restore vision when the retina can no longer do its job. For example, it may be possible to compensate for malfunctioning retinal ganglion cells by introducing plant-based genes that produce channels sensitive to light and that are capable of generating electrical activity in the cortex when stimulated by light.

Leti, a CEA Tech institute, Clinatec, and the Institut de la Vision* are engaged in the DARPA**-funded CorticalSight project, which will explore this potential solution. An eyeglass camera films the patient's environment in high resolution. The resulting images are then pre-processes using complex algorithms that transform the visual information into light signals that can be interpreted by the brain. The signals are transmitted wirelessly to a system implanted in the patient's brain, and then sent to an array of optical micro-sources that stimulate specific neurons of the visual cortex that have been made sensitive to light by a microbial opsin—in other words, optogenetics.

An intermediate demonstrator will be developed by Clinatec in 2018. The demonstrator will be used to assess the system's capacity to stimulate cells and tissue in culture before animal testing begins.

*Inserm, Université Pierre et Marie Curie, CNRS

** United States Defense Advanced Research Projects Agency