Without the glasses? That’s the whole point of the film! Newman said, “We’re kind of exploring different versions of what is that thing that allows you to see. But I’m not going to tell you what it is…It might be something different than sunglasses.”
There was no real reason given though reading between the lines, they seem to want to both modernize the tale while giving it a little extra dose of reality. I think in a world where 3D has gone mad, using glasses would be a still-relevant touch. And the reluctance of people to try on sunglasses from a crazy homeless guy is exactly what leads to Rowdy Roddy Piper fighting Keith David for five minutes!
Let’s hope cooler heads prevail and they can keep the sunglasses in the film. Otherwise it’d be like TRON: LEGACY without the identity discs…