Researchers Improve Technology Used To Restore Vision in Fully Blind

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A team of Stanford University researchers has published impressive results from a recent study testing a new wireless retinal implant designed to restore vision to the fully blind. The concept itself is not new. In 2013, researchers with the University of Michigan’s Kellogg Eye Center developed a device called the Argus II and implanted it in 50 fully blind patients, resulting in vision restoration and an average visual accuracy of 20/1200. Since then, the Argus II has received FDA approval as a treatment option for a degenerative vision disorder called retinitis pigmentosa, which causes blindness by destroying the rods and cones in the retina. Now, researchers at Stanford have improved this technology and are reporting that, in lab rats, they were able to restore vision to 20/250.

Vision restoration of any kind in patients who are fully blind is a relatively new achievement in medicine. With the Argus system, users wear a pair of glasses outfitted with a video recorder and an implanted receiver placed inside the eye just past the damaged retina. Images are captured by the recorder and then sent to a computer worn on the hip, where they are converted into a series of pixels and then wirelessly transmitted to an implanted chip in the eye. The implant is a sheet of electrodes that presents the images in the form of rudimentary black and white dots in the wearer’s field of vision, bypassing the damaged retina, and replicating, at a very basic level, the retina’s function. This technology is capable of delivering 20/1200 vision to patients that were once fully blind, which is enough to allow them to walk down a sidewalk unaided, read letters on a computer screen, or match and fold pairs of colored socks.

At Stanford, researchers claim that they have developed technology that may improve on these results. The technology relies on a similar set of technology: a video-recording headset and an implanted sheet of photosensitive electrodes. Rather than completely bypassing the damaged retina, as the Argus II does, Stanford researchers have designed an improved implant that takes advantage of a portion of retina that is generally not damaged by degenerative visual diseases like retinitis pigmentosa. Stanford’s implant incorporates the retina’s bipolar cells, which are found just past the damaged rods and cones in the retina. The retina’s bipolar cells are electrically excited by the implant and then visual data is reintroduced, passing through the bipolar cells and then moving on to the optic nerve and the brain. By incorporating these bipolar cells, researchers are reintroducing some of the eye’s natural abilities and as a result, are seeing notable improvements in vision over the Argus II. Daniel Palanker, PhD, the lead researcher on the project, says, “Eventually, we hope this technology will restore vision of 20/120, and if it works that well, it will become relevant to patients with age-related macular degeneration.”

It’s important to note that the method outlined by the Stanford team has yet to be tested on a human, but clinical trials are currently being planned in France in partnership with a company called Pixium Vision.



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