HMD's are a pretty good solution to VR, but there are still a number of unsolved problems which can't be addressed by higher pixel density, faster refresh, and

HMD's are a pretty good solution to VR, but there are still a number of unsolved problems which can't be addressed by higher pixel density, faster refresh, and more powerful GPUs. For instance, how do you account for the focal adjustments your eye makes when you look at objects at different distances in a virtual scene when you are staring at a screen only a short distance from your face?