A system includes: a first movable stage which is movable with respect to an eye of a subject; a second movable stage mounted on the first movable stage, wherein the second movable stage is movable with respect to the first movable stage; a fixation target disposed on the second movable stage; and an optical system disposed in an optical path between the fixation target and the eye, wherein the optical system is configured for projecting the fixation target upon the eye to accommodate the eye, and wherein moving the second movable stage to a position where the fixation target is moved away from the eye by an additional amount causes blur cues of the fixation target to indicate to the subject that the fixation target is moving away from the eye while the size of an image of the fixation target on the retina of the eye decreases.