Double Vision (Diplopia): Causes & Treatment

Double vision, or seeing double, is when you see two images of the same object. The medical term for this symptom is diplopia. Double vision can be a sign of an underlying problem with your eyes. It can also be a symptom of certain medical conditions. Approximately 800,000 people visit a doctor each year in the US for double vision.

Having double vision can make depth perception, walking, and driving difficult, putting you at risk of accidents and injuries. Fortunately, in 9 out of 10 cases, it is a temporary double vision with no long-term health effects. But sometimes, diplopia can signal a more serious underlying health condition.

If you notice any changes in your vision, such as double vision or blurred vision, you should make an appointment to see your healthcare provider. In the meantime, here are some possible causes and treatment options for diplopia (double vision).

What are the different types of diplopia?

When you have double vision in only one eye, it is called monocular diplopia. When double vision affects both eyes, it is called binocular diplopia. Binocular diplopia is present when both eyes are open and disappears when you close one eye. It is less common but more serious than monocular diplopia.

Doctors also classify diplopia as horizontal and vertical. Horizontal diplopia is when one image appears to the side of the other. Vertical diplopia is when a double image appears below the other.

Sometimes the double vision is present in specific circumstances, such as looking at near or far objects or looking in a certain direction. The type of double vision can give your eye doctor clues about the underlying cause.

What is the most common cause of diplopia?

Various conditions can lead to double vision. It’s important to see an eye specialist so they can obtain a health history, perform an eye exam, make a proper diplopia diagnosis, and treat diplopia appropriately.

Common causes of monocular diplopia include:

Dry eye syndrome
Astigmatism (imperfect curvature of the eye)
Cataract (clouding of the lens in the eye)
Poorly fitting eyeglasses or contact lenses
Problems with the iris (colored part of the eye)
Corneal scarring

Possible causes of binocular diplopia include:

Eye misalignment (one eye sees an image in one location, and the other eye sees a ghost image in another location)
Problems with the cranial nerves, such as a cranial nerve palsy
Stroke
Brain aneurysm
Brain tumors

Double vision occurs in certain health conditions such as:

Head injuries involving the eye socket
Myasthenia gravis due to droopy eyelids and weakness of the extraocular muscles (eye muscles)
Multiple sclerosis due to nerve damage to the nerves that control eye movement
Problems with thyroid function, such as hyperthyroidism (overactive thyroid gland) and Graves’ disease due to proptosis (bulging of the eyes)
Keratoconus due to bulging of the cornea (the clear part of the eye)
Diabetes due to damage to the eyes from diabetic retinopathy

What symptoms can accompany temporary double vision?

Other symptoms that are commonly present along with double vision include headache, dizziness, vertigo (a sensation of things spinning around you), nausea, eye pain, and blurred vision.

Your eye doctor will perform an eye exam to diagnose double vision. They will find out if you have monocular or binocular diplopia. If you have monocular double vision, you may not need any further testing. However, if you have binocular double vision, your doctor may order blood tests and imaging (MRI, CT scan) to find out what’s causing it.

Can diplopia go away?

Yes, diplopia is usually temporary and goes away once the underlying condition is treated. If double vision becomes a permanent problem, i.e., if it persists beyond 12 months, your eye doctor may recommend a surgical procedure on your eye muscles to prevent two images from forming.

What is the best treatment for double vision?

Treatment options depend on the causes of double vision. For example, if your glasses or contacts are the reason for your double vision, a new pair of glasses or properly fitted contacts may fix the vision problem. When astigmatism is causing temporary diplopia, corrective lenses can solve the issue.

If cataracts are the underlying cause of your vision problems, you will find that double vision disappears after cataract surgery. Surgery and other treatments may be necessary if you are diagnosed with a serious condition such as a brain tumor.

If you have an underlying condition that affects eye muscles, your doctor may recommend vision therapy. This may involve learning eye exercises to make your eye muscles stronger.

Wearing an eye patch can be a useful treatment (double vision that is binocular usually disappears when you close the affected eye).

Is diplopia serious?

Make an appointment to see your eye doctor if your diplopia lasts more than a week or two. You should seek immediate medical attention in the nearest emergency department if you have double vision along with pain, dizziness, weakness, slurred speech, or confusion. Do not ignore diplopia as it can be a sign of a serious issue such as an aneurysm or stroke.

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