Current retinal prostheses restore only limited and fuzzy vision to people who have become blind because of eye disease. A coming generation of retinal implants will fit entirely inside the eye; the nano-sized electronics could someday give blind people 20/20 vision, Technology Review reports.
Second Sight’s Argus II, the first ‘bionic eye’ to reach commercial markets, contains an array of 60 electrodes implanted behind the retina to stimulate the remaining healthy cells; a similar implant from Bionic Vision Australia uses 24 electrodes.
These existing implants are connected to a camera, worn on the side of the head, that relays a video feed. Second Sight also recently announced a method by which Argus II wearers are able to visualize Braille instead of traditional text.
To increase the amount of visual information transmitted to the brain, both Second Sight and Bionic Vision Australia have announced that they’re developing devices with 200-plus electrodes.
With arrays of nanoscale electrodes, smaller electrodes can get closer to individual nerves to give higher-resolution images. And you can have more of them.
In Israel, a company called Nano Retina has an implant that consists of 676 electrodes, all small enough to fit onto a single, tiny implant. And, the device requires no external camera or wires. A prototype “worked beautifully” in pigs, and the company is now building a human prototype that could have up to 5,000 electrodes. The company hopes to enter clinical trials within two years.
A team at the University of California, San Diego, is using nanotechnology to directly mimic cells found in the eye. An implant of silicon nanowires mirror the form, distribution, and function of natural photoreceptors – combining light detection and neuron stimulation in a single material. The team is testing their device in rabbits.
[Via Technology Review]
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