[endisneigh]

yes I used Google Glass for a year. it definitely obscures your vision compared to not using it.

it's funny you mention games because most games I've been playing have been moving away from having a HUD visible all of the time, and only show it contextually.

[mdp2021]

I tend to believe from other people's reports (also in this page) that Google Glass works differently from more recent systems. Translucent augmentational data, augmentational data and environment co-present and just eye-focus away in focus do not seem to obscure the vision. Personal experience, though not used at high speeds.