How long can double vision last for?

Depends on cause: This will depend on the cause of the double vision and can be from seconds to permanent. See an ophthalmologist.

Double vision : Depends on the cause. If the double vision is due to a refractive problem, it usually can be corrected with glasses. If the double vision is due to a neurological problem affecting the alignment of the eyes, it will depend on the cause of the neurological problem.