Like we could have navigational AR-glasses. The wearer sees arrows on the floor where to walk. And we could choose to not let anyone wear them in public even though what they do is useful, and there aren't any real privacy issues. But people around the wearer don't know that. That's the privacy concern.
The form factor of the camera doesn't matter. We do have different constraints, but those are pretty solidly filled out in case law. I don't believe making recording glasses illegal to wear in public would withstand constitutional scrutiny. Mandating a visible notification with a conventional color, signaling things like "on" "passive" and "recording" would be constitutional and wouldn't infringe. That said, surreptitious use would likely be legal, e.g. aftermarket modification to allow recording with no lights; first amendment issues have a high bar and all sorts of secret camera precedents being legal. This is how corrupt politicians and cops and officials get caught, all the time, and it's highly unlikely to be smart glasses that gets the people and courts to flip on 1A.