It's also (mostly) solvable with active lenses and eye-tracking. What you can do is infer distance from vergence and then adjust the effective focal distance of

It's also (mostly) solvable with active lenses and eye-tracking. What you can do is infer distance from vergence and then adjust the effective focal distance of the screen. I don't know how cumbersome the lenses would have to be, or how insanely fast the system would need to operate, but it's at least possible in theory.