When light hits Barbara Campbell's eyes, it triggers no response in her retinas, and no signals flash up her optic nerves to her brain. A genetic disease killed off her retinas' photoreceptor cells, leaving her completely blind by her 30s. But where her body failed her, technology rescued her. In 2009, at the age of 56, Campbell had an array of electrodes implanted in each eye, and she now makes her way through the world more confidently, aided by bionic vision.
Her sight isn't fully restored, not by a long shot, but the darkness has been replaced with rough shapes and patterns of light and dark. "The building where I live has a large light at the entranceway outside," says Campbell, who lives in New York City. "I hadn't been able to see that light in 16 years. Now, when I'm walking down the block, I can look up and identify the building."
The devices in Campbell's eyes come from Second Sight Medical Products. After 13 years of product development, the company's Argus II Retinal Prosthesis System is now hitting the market. In 2011 the company won regulatory approval in Europe [PDF], and eye surgeons there are just beginning to perform the implants. This year the Los Angeles–based company hopes to get approval from the U.S. Food and Drug Administration as well. "I didn't think it would take this long," says CEO Robert Greenberg, "but it's finally real."