Seeing without eyes
Researchers want to make blind people see something again with implants that feed visual signals directly into the brain. However, there are still a few hurdles between them and their goal.
"Our volunteers will be like the first astronauts sent into space by NASA. They will explore a new frontier of science," announced Philip Troyk in a video conference in November 2020. The 30 people who attended take part in it, listen attentively to his words. They have all lost their eyesight in the course of their lives and until now there has been no way for them to ever regain it. Troyk's project, which sounds a bit like science fiction, seems like a unique opportunity: the American bioengineer wants to use experimental implants directly in the brain to give blind people visual perception.
But the artificial vision that Troyk promises is fundamentally different from the natural one. In the latter, receptors in the retina of the eye react to the light. The signals they send then travel via the optic nerves to the primary visual cortex at the back of the brain. Individual neurons in this brain region represent a tiny area of the visual field - similar to a pixel on a computer screen. The area from which a neuron receives a signal is not arbitrary. Neighboring cells process light stimuli detected in the eye by closely spaced photoreceptors. Information travels from the primary visual cortex to other brain regions. There, points are combined into lines, lines into shapes, and finally shapes into objects.
Troyk warns the participants in the video conference against exaggerated expectations of the visual prosthesis. "You won't be able to recognize the faces of your loved ones the way you remember them," he explains…
