Why you won't see hard augmented reality any time soon

I have a question I haven't seen answered anywhere: How does these glasses work with focus? When I'm looking (and focusing) 5 meters away, how can I see an object overlaid there? Surely, I'd have to focus on the glasses, 3 cm from my eye, no?

How do they fix that?

At a guess, it would track iris dilation to determine your focus depth.

I'm not really sure it's active, but still, the question of how you get something on a surface to become visible when you focus meters beyond that surface remains.

Iris dilation is primarily a response to light levels, not focus depth. Focus comes from stretching the lens behind the iris, which is possible to sense externally, but much more difficult.

You can use lenses or mirrors to change the apparent focal distance of an object. Google's implementation is rumored to use holographic optical elements instead, probably for compactness: http://www.google.com/patents/US3940204

Ah, very interesting, thank you.

Duplicate: http://news.ycombinator.com/item?id=4273724

I can't wait until "AR and driving" is like "texting and driving"