Inside your eye are tiny retinal cells whose job is to translate the visual signals you encounter every day — colors and edges — into signals your brain can understand. Without these photoreceptors, you can’t see. And retinal degeneration, in which these receptors start to die off, is one of the leading causes of blindness.
But one group of scientists may be nearing a solution. In a paper published in the journal Nature Medicine this week, researchers describe a tiny, honeycomb-shaped wireless implant that helps restore vision in rats with retinal degeneration. These rats had lost some of their light-sensitive cells , but they still had intact bipolar and ganglion cells — the cells that photoreceptors hook up to. By using the wireless implant to directly stimulate these cells, researchers were able to restore partial vision to the rats.
In a nutshell, the way the procedure works is that when light hits the eye, the wireless device sends an electrical impulse to bipolar cells, which get activated. These then activate ganglion cells. Ultimately, that signal gets passed to the optic nerve, which relays the signal to the part of the brain than deals with vision. Because the brain gets a series of electrical pulses that encodes what the device is “seeing,” it’s able to create a representation of it. The representation isn’t as nuanced as what a normal eye would produce, so it doesn’t restore perfect vision (the rats in the experiment only saw half as well as normal rats), but it’s a vast improvement.
The implant has only been tested in rodents so far, but its big potential advantage — if scientists can make it work in humans — is that it doesn’t require an external energy source. Once it’s been surgically placed in the eye, the implant transforms some of the light it captures into electrical current that powers it.
To read the rest of this article, published in Fusion.net, please click here.