Um, because stereo vision gives us the ability to judge distances?

It used primitive model-based stereo vision to locate and track objects in its environment.

The mental process behind construction of the Cyclopean image is crucial to stereo vision.

An eye patch can be worn on one eye as stereo vision is difficult to simulate.

Through stereo vision, the primary cue for human depth perception, the brain interprets the images as being in three dimensions.

The eyes where partly slanted forward, giving it at least partial stereo vision.

The device was used to explore his theory of stereo vision.

Its purpose was to test his theory of stereo vision and for investigations into what would now be called experimental psychology.

Consider stereo vision, by which we estimate the size of things directly, does not work beyond twenty feet or so.

Ironically, the director de Toth was blind in one eye, and unable to experience stereo vision or the 3-D effects.