Why am I seeing in double vision?

A problem with seeing things clearly can be alarming, particularly if it is a sudden change. Double vision can be particularly disconcerting, as it can affect your ability to work and enjoy leisure pursuits. It also makes driving dangerous and impossible unless it is corrected.

What is double vision?

There is a myth that double vision is seeing two things next to each other. In fact, the double image can be in any direction, including having the same item top and bottom.

Double vision describes seeing things unclearly because you are receiving information to your brain independently from both eyes. Normally the eyes transmit an image in tandem, which the brain can interpret as a three-dimensional image.

Causes of double vision

The medical term for double vision is diplopia and there can be various reasons for it. It can also be attributed to issues with one, or both of your eyes.

In childhood it can be the result of problems with the muscles and nerves behind the eyeball. This developmental anomaly results in conditions such as “squints” and having crossed eyes which work independently when focusing.

Several childhood issues resulting in double vision can be corrected by surgery. Or, some respond well to non-invasive therapies such as wearing a patch for a “lazy eye”.

As an adult, if you start to experience episodes of double vision it could be due to excessive use of alcohol or recreational drugs. A nerve or muscle problem from childhood can also reappear in later years.

Other causes include problems with your thyroid gland, which affects the muscles in your neck which in turn impacts on your eye movements. Also, a stroke or aneurysm (bulge in a blood vessel) pressing on an eye nerve, can both affect the ability of your eyes to create a tandem image.

Problems with double vision can also arise from a bad knock on the head or fall.

Seek medical help

Any form of double vision should result in seeing an optometrist, particularly as it can create risks for driving or carrying out other everyday tasks safely. It can impact negatively on your balance and depth perception.

Treatment for double vision can involve surgery or corrective lenses. You may be provided with eye exercises too, which sometimes help to rectify the situation.

If your double vision is sudden and persistent it could be due to injury to your head or one of the serious medical issues mentioned above. Particularly if it is accompanied by severe headache and nausea you must seek medical advice straight away.