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.