n. double vision: the simultaneous awareness of two images of one object. It is usually due to limitation of movement of one eye so that the two eyes cannot simultaneously look at the same object. This may be caused by a defect of the nerves or muscles controlling eye movement or a mechanical restriction of eyeball movement in the orbit (binocular diplopia). Double vision that does not disappear on covering one eye (monocular diplopia) can be caused by early cataract (see also polyopia).... diplopia
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