Double vision or diplopia is the perception of two images of a single object. Looking at something and seeing a single clear image is something we take for granted, giving no thought to the different areas of the visual system that need to work together to allow us to see this image.

The cornea, the clear membrane over the front of the eye, focuses most of the light entering the eye. The lens helps to focus light onto the retina at the back of the eye. The muscles of the eye move the eye in different directions. Nerves carry information from the eyes to the brain. A problem with any part of this delicate system can lead to double vision.

Double vision can be monocular, affecting one eye only, or binocular, occurring in both eyes.

Causes of Double Vision

Problems with the cornea that can cause double vision include infections which can distort the cornea, and scarring or dryness of the cornea. This usually affects one eye only.

Cataracts are the most common problem with the lens that can cause double vision. If cataracts are present in both eyes, images from both eyes will be distorted. If the eye muscles are weak, for whatever reason, they cannot control the movement of the eyes effectively, and double vision is experienced. This muscle weakness can occur in one eye or in both eyes, and can be part of a general health condition.

There are various conditions that may damage the nerves that control the eye muscles, leading to double vision. These include multiple sclerosis, strokes and other brain conditions.

Symptoms of Double Vision

Double vision is sometimes confused with blurred vision. In the case of blurred vision, one perceives one image which is unclear, while with double vision there are two images of only one object.

Double vision can occur with no other symptoms, or depending on the cause, other symptoms may be present. Common symptoms are misalignment of one or both eyes (a "wandering eye" or "cross-eyed" appearance), pain with eye movements in one or both eyes, pain around the eyes, such as in the temples or eyebrows, headache, and nausea. Migraines are often associated with double vision.

Double vision affects people in different ways. Some patients may experience double vision occasionally, while others have it all the time. Some people say they only experience double vision when they are looking in a specific direction.

Anybody who develops double vision should see about it immediately.

How Is Double Vision Diagnosed?

There are multiple ways of diagnosing double vision, depending on the underlying cause.

One of the most effective methods is the information you can provide, by answering several important questions:

When did the double vision start?

Did it start suddenly?

Have you hit your head, fallen, or been in an accident?

Is the double vision worse at the end of the day or when you're tired?

Have you had any other symptoms besides double vision?

Do you tend to tilt your head to one side to see an image clearly?


With double vision, the most important step is to identify and treat the underlying cause. In many cases, double vision can be improved by managing or correcting its cause.

If double vision can't be reversed, certain treatments can help people manage it in their daily lives. Sometimes, this requires wearing an eye patch or a contact lens which blocks vision in one eye. Special prism glasses may be prescribed; the prism bends the light and shifts the image, in order to minimise the effect of double vision.

Double vision in children

Because children are less able to express what is wrong with their eyesight than adults are, a child may not complain of double vision, but parents or teachers may be able to detect certain signs. A child with double vision may narrow the eyes or squint when trying to focus on something. Some children may close or cover one eye in an attempt to focus. If a child tilts his head frequently when looking at something it could be a sign of double vision.

Childhood double vision can be treated more effectively if diagnosed early on.

n, presbyopia can interfere with the comfortable performance of daily activities, so it is advisable to visit your optometrist regularly after the age of 40.

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