Augmented reality will put guide dogs out of business

I quite like guide dogs but the AR equivalent, something that can sense
the world around it and augment the user's senses via audio, is an
obvious step. Someone must be working on a device like this already.
It's a totally obvious augmented reality application. In fact I think of
it because I'm reading about one of the early AR implementations to help
guide visually impaired people using a GPS.