[Coincoin]

A real hologram, like in your last link, make the photons actually come from the correct angles so that everything is not in focus in your eye.

Stereo imaging we see in current VR and TV technologies do not simulate that effect, which makes it hard for some people to use as everything is focused at infinity or on the screen. What the lens (in your eye) is currently focused on is a very important depth cue for our brain and the conflicting information coming from the lens and stereo vision make some people unable to use stereo imaging or cause eye pain and headaches.

Unfortunately, real holograms are currently restricted to static images meticulously constructed using very advanced equipment that produces seemingly random images on films that interfere with each other to produce the hologram. Doing the same thing with moving images in real time would require too much computing power to currently be possible.

Another way could be to track the lens refraction properties and the pupil size in real time and fake some depth of field on the projected stereo images.