Most of us take our eyesight for granted—until something goes wrong with it. Vision is a lot more complicated than we are aware of, and things can go at various points in the process, leading to changes in your vision.
Seeing double is a sign that something has gone wrong with the process. It should be taken seriously, because the underlying reason could require immediate treatment.
What to look out for
Double vision can happen on its own, with no other symptoms. However, there might often be other clues that will give you an idea as to the cause, including:
- A “wandering eye” or “cross-eyed” appearance, which shows some form of misalignment in the eye
- Pain when you move your eye/s
- Pain around your eyes, such as around the area of your eyebrows or your temple
- Weakness in your eyes or anywhere else in your body, such as an arm or leg
- Drooping eyelids
There are various underlying causes of misalignment, such as thyroid issues and nerve issues. Common causes of nerve issues include diabetes, multiple sclerosis (MS) and Guillain-Barre syndrome.
Your double vision might also be caused by issues with the brain itself, including:
- Stroke (the sign of which is trouble speaking or using limbs, for example)
- Increased pressure inside the brain from trauma, bleeding, or infection
- Brain tumors
What to do if you see double
If it suddenly occurs, treat it as a medical emergency and see your eye doctor. They will run tests and might also send you to a diagnostic center for a computed tomography (CT) scan, or magnetic resonance imaging (MRI) of your head.
They will ask you various questions, such as when it started, and whether you have had any trauma to the head. They will ask you to describe the vision as well, and whether it is clear or blurry. They will test both eyes as well, to determine if you are seeing double out of one or both. Depending on your answers to these and other questions, your doctor should be able to get to the bottom of your double vision and offer treatment options.