Touch sensors on the tongue are used instead of the photoreceptors of the eye.

BBC: TV & Radio examine disability act

The goal was to substitute photoreceptors with a light-sensitive material capable of restoring photosensitivity to the retina, by easing down the retina on a layer of organic photovoltaic semiconductor.

FORBES: Artificial Retina From A Photovoltaic Polymer

In their study, the researchers used mammalian retinas with a degeneration of photoreceptors in order to have an experimental model of different degenerative pathologies of the retina, such as Retinitis Pigmentosa or macular degeneration.

FORBES: Artificial Retina From A Photovoltaic Polymer

The artificial retina is composed by neuronal photoreceptors, called cones and rods, which capture light signals and transform them in electrical signals, transferring them to the retinal ganglion cells and, through the optic nerve, to the brain.

FORBES: Artificial Retina From A Photovoltaic Polymer

Scientists are also unsure about the quality of vision that could be restored from stimulating nerve cells alone, as, in normal circumstances, there is a sigificant amount of visual processing that occurs between the photoreceptors and the nerve cells.

BBC: NEWS | Health | Spinach may hold blindness cure