If someone is suffering from double vision, they see a single object as two objects, for example because they are ill or have drunk too much alcohol. A disorder of vision in which a single object appears double. Also called diplopia. a medical condition in which you see two objects instead of one all the time, for example after an accident. or diplopia Perception of two images of an object, usually caused by temporary or permanent eye-muscle paralysis. Normally, the brain fuses slightly different images from each eye by matching corresponding points on each retina. When an eye muscle is paralyzed, the image falls at a different point and the images do not correspond. Double vision may be an early symptom of botulism or myasthenia gravis and occurs in other infections, head injuries, and nerve or muscle disorders