For fusion and space perception testing (e.g., stereoscopic vision):
(under subclass 200) Subject matter including instruments used for testing simultaneous binocular vision for determining space perception and determining the condition of prismatic imbalance, both vertically and laterally, of a pair of eyes.
(1) Note. The above instruments may polarize the light in crossed planes coming from the different portions of a target, or may present pairs of half stereograms to the respective eyes, or may present a plurality of independently movable targets so that the correct optical positions for true image convergence or true stereopsis are obtained.
