Double vision, also called diplopia, causes a person to see two images of a single object. There are two types of double vision: monocular and binocular.
Monocular diplopia is double vision in only one eye. The double vision continues even when the other eye is covered. The doubling does not go away when you look in different directions.
Binocular diplopia is double vision related to a misalignment of the eyes. The double vision stops if either eye is covered. Any problem that affects one or more of the muscles around the eyeball that control the direction of the gaze can cause binocular diplopia. These are called extraocular muscles.
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