It sounds completely crazy: as early as next year, using gene therapy scientists hope to restore sight in the blind by giving their eyes additional “light sensors.” We’re not talking about bionic eyes: instead of implantable electronics, scientists are turning to a protein called channelrhodopsin-2. You’ve probably heard of this protein before — it’s the same magical switch that, in response to light, can turn a gentle mouse aggressive, shut down obsessive grooming behavior, and…