Second Sight left users of its retinal implants in the dark. IEEE Spectrum reports: Barbara Campbell was walking through a New York City subway station during rush hour when her world abruptly went dark. For four years, Campbell had been using a high-tech implant in her left eye that gave her a crude kind of bionic vision, partially compensating for the genetic disease that had rendered her completely blind in her 30s. “I remember exactly where I was: I was switching from the 6 train to the F train,” Campbell tells IEEE Spectrum. “I was about to go down the stairs, and all of a sudden I heard a little ‘beep, beep, beep’ sound.” It wasn’t her phone battery running out. It was her Argus II retinal implant system powering down. The patches of light and dark that she’d been able to see with the implant’s help vanished.