The lens can be directional focusing your vision onto a certain point, also your peripheral vision cannot discern as much detail. They've stated it is on a chip the size of a postage stamp. So we'll have to see how the lens directs it, when it's released.

Edit:sort of a Magic Leap type thing. The further out you look from the centre of the lense, the more the lense curves back to the focus your eye on the centre. With the eye tracking changing the image to compensate for your eye movement.

Unless they're magically changing the shape of the lens in response to eye movement that doesn't seem physically possible.

What if they shift screens mechanically in response to eye movement? Similar like apple camera optical stabilization works by shifting slightly camera sensor array? And if the screen pixel density is not uniform but more dense in the center? Hard to pull off but I guess not impossible.

Even if that where possible, I doubt that the accuracy of the eye-tracker is sufficiently high for this approach to work.