Double vision is seeing two images of a single object. It's sometimes confused with blurred vision.

If you have blurred vision, a single unclear image will appear. If you have double vision, you'll see two images at the same time. Double vision may be constant, it may come and go, or it may only occur when you're looking in a particular direction.

A weakness in the muscles on either side of your eyeball can cause horizontal double vision, where you see two images side by side while looking to the left or right. It can also cause your eyes to appear "crossed", or as if they are wandering.

Visit your GP as soon as possible if you develop double vision, particularly if you haven't had it before. It could be a symptom of a serious medical condition.

Recognising double vision in children

Adults are able to describe what is happening with their sight, but young children may not be able to explain clearly what is wrong.

If your child has double vision, they may narrow or squint their eyes in an effort to see, or they may frequently cover one eye with their hand. They may also turn their head in unusual ways, or look sideways instead of facing forward.

Sometimes children may also look between the two images. However, they usually quickly learn to ignore one image. This process is called suppression and can lead to permanent loss of vision in that eye (amblyopia).

If you suspect your child has double vision or a squint, take them to see your GP as soon as possible. It's very important the condition is diagnosed and treated quickly.

Read more about diagnosing double vision.