Double vision (diplopia) is when you look at one object but see two images. The NHS says it is not usually serious, but it is important to get it checked, even if it comes and goes. An optician or GP can do some simple, painless tests and refer you if needed.
Children often cannot tell that they have double vision. Signs include squinting, closing or covering one eye, tilting the head, or looking at things sideways.
When it is urgent
Ask for an urgent GP appointment or get help from NHS 111 if you have eye pain with double vision, or double vision that started suddenly. Call 999 or go to A&E if you have a severe headache or an enlarged pupil with blurred or double vision, or double vision after a head injury.
A simple check
The NHS suggests covering one eye at a time. If the double vision goes away with one eye covered, it is probably affecting both eyes (binocular), which is usually a symptom of a squint. If you still see double in the uncovered eye, it is probably affecting just that eye (monocular), which is usually caused by an eye problem such as dry eyes, astigmatism, cataracts or keratoconus.
Treatment
Treatment depends on the cause. It may be simple, such as eye exercises, an eye patch, or glasses or contact lenses, or some causes may need eye surgery.
Driving
The NHS says you must stop driving and tell the DVLA if you are diagnosed with double vision. You can drive again if a doctor tells the DVLA it is safe.
