Because the eyes are separated by several centimeters, each eye's view of an object is different from the others. this is called disparity.

Because the eyes are separated by several centimeters, each eye's view of an object is different from the others, this is called Binocular disparity. "Bi" coming from "two" and "ocular" referring to optics and the lenses of the eye, when the images of both eyes are combined they create depth perception, which allows humans to distinguish distances visually. 

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