Double vision (diplopia) is when you look at one object but can see two images.  It may affect one eye or both eyes.

See an Optometrist/optician or GP if you or your child have double vision.

Signs that your child may have problems with their vision include:

  • narrowing or squinting their eyes to try and see better
  • covering one eye with their hand
  • turning their head in usual ways (for example, tilting their head)
  • looking at you sideways instead of facing forward

It's important to get double vision checked out, even if it comes and goes.  It's sometimes a symptom of a serious condition.

Children under 19 in full time education are entitled to a free sight test under the NHS. If as an adult you get sudden new double vision, in Wales most Optometrists can see you free of charge.

Find an optometrist/optician here.

Ask for an urgent appointment or go to A & E if you have:

  • eye pain and double vision
  • a severe headache with blurred or double vision

What happens at your appointment

Your Optometrist/optician will ask about your symptoms and do some simple, painless eye tests.  They may refer you to an eye specialist in hospital for tests and treatment.

Your Optometrist/optician may also suggest you see your GP to check for general health conditions that can cause double vision.

Treating double vision

Your eyecare team can advise you about the best treatment for double vision once they work out the cause.

In some cases, this may be simple treatments such as eye exercises, wearing an eye patch or being prescribed glasses or contact lenses.

Some conditions that cause double vision may require eye surgery to correct the problem.

Causes of double vision

Double vision has many possible causes, depending on whether one eye or both eyes are affected.

Try covering one eye at a time to see if your double vision goes away. 

If you still have double vision in one eye with the other one covered, it's probably only affecting that eye.

Double vision affecting both eyes (binocular)

Double vision affecting both eyes is usually a symptom of a squint (or strabismus).

This is where problems with the eye muscles or nerves cause the eyes to look in slightly different directions.

Squints are more common in children but they don't always cause double vision. An untreated squint in children under 7 causes a lazy eye instead.

Squints in adults are sometimes a sign of a more serious condition.

Double vision affecting one eye (monocular)

Double vision affecting one eye is less common. It's usually caused by eye problems such as:

  • dry eye syndrome – where the eyes don't produce enough tears
  • astigmatism – a common condition where part of the eye isn't a perfect shape
  • cataracts – cloudy patches over the front of the eyes
  • keratoconus – where the clear outer layer of the eye (cornea) gets thinner and changes shape


You must tell the Driver and Vehicle Licensing Agency (DVLA) if you're diagnosed with double vision as it could affect your ability to drive, your Optometrist/optician or eye care team in hospital will be able to give you more advice on this subject

Find out how to tell the DVLA about double vision (diplopia).

Call NHS 111 Wales

If you can't speak to your Optometrist or GP or don't know what to do next call NHS 111 Wales if available in your area or 0845 46 47.

The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 28/10/2021 07:28:39