If you have double vision, your GP will probably refer you to an ophthalmologist (eye specialist) at the eye department of your local hospital.

Ophthalmologists commonly work in a team with:

• orthoptists – specialists in problems relating to eye movements and how the eyes work together 
• optometrists – who carry out eye examinations and assess your need for glasses

Initial tests

The first step in diagnosing double vision is to establish whether your double vision affects:

• both eyes (binocular double vision)
• one eye (monocular double vision)

Read more about the causes of double vision.

Sight tests

Your eyecare team will usually start by assessing your vision. They may ask you to read letters off a chart, look at the position of your eyes, and assess how well you can move them. They may also assess how well your eyes are working together (your binocular vision).

Your ophthalmologist will also use a microscope with a very bright light, called a slit lamp, to examine the front and back of your eyes.

These results, together with your medical history and any other symptoms you have, should determine what could be causing your double vision. 

Read more about treating double vision.

Further tests

Further tests may include blood tests. A picture of your brain or eye muscles may also be taken using: 

• a computerised tomography (CT) scan – this takes a series of X-rays at slightly different angles and uses a computer to put the images together 
• a magnetic resonance imaging (MRI) scan – this uses a strong magnetic field and radio waves to produce detailed images