The focal point is a problem. It is advised to keep your screen at >65cm so your eye doesn't have to accomodate (coincidentally, the length of your arms). A big

The focal point is a problem. It is advised to keep your screen at >65cm so your eye doesn't have to accomodate (coincidentally, the length of your arms). A big problem of Google Glass is the focal point is a few cm away and it is known to give headaches. The smaller the screen is, the more myopic you become. It is absolutely possible to use a lens system to move the focal point to the distance, but hasn't been done yet, probably because you can't do it on 120x120 degrees. I wouldn't work on a virtual screen for long hours until there's an answer to that. But once it is solved, I can see how we'll all become Holographic addicts ;)