Answer:
In front of: behind
Step-by-step explanation:
Points which appear closer to us than the horopter have crossed disparity.
Points which appear farther away from us than the horopter have uncrossed disparity.
Crossed disparity involves objects that are in front of the plane of fixation which makes it appear closer while uncrossed disparity involves objects that are behind the plane of fixation which makes it farther away from the eyes.