Double Vision (Diplopia)

What is double vision (diplopia)?

Double vision is when you look at a single object but see two images. The medical term for this issue is 'diplopia'. Some people's double vision is temporary. For others, it may come and go. Or, it might be a constant issue. It can appear suddenly or develop over time.

Living with diplopia

Double vision can be worrying and disruptive. It may make everyday tasks like driving, playing sports, using a computer, reading, or watching TV difficult, impossible or unsafe.

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Types of double vision

There are three main kinds of diplopia.

Double vision in one eye (monocular double vision) 

This is when you get double vision in one eye. If you close the affected eye, your vision in the other eye is clear, and the double image goes away. It’s usually caused by a problem within one of the eyes.  
Learn more about eye conditions.

Double vision in both eyes (binocular double vision) 

This is when you see two images of the same object with both eyes open. If you close either eye, your vision clears up. It's often a sign that there's a problem with how your eyes work with each other, or an issue with your nerves or brain.

Temporary double vision 

You may get temporary double vision after drinking too much alcohol, taking other intoxicants, or when you're extremely tired. You may also get double vision after a knock to the head ‑ this needs to be checked by a medical professional.

You can also experience voluntary double vision which is when you intentionally cross your eyes. For example, when looking at a stereogram image.

Diplopia can be an emergency

Double vision isn’t usually a medical emergency, but there are times when you should seek urgent care. 
 
Contact your GP for an urgent appointment or call Healthdirect on 1800 022 222 if you have double vision with pain in or around the eye, if it came on suddenly, or if it hasn’t gone away after a few hours. 
 
Call Triple Zero (000) or go to the emergency department straight away if you have a severe headache and enlarged pupils along with double vision, if it started after a head injury, or if you also have slurred speech, confusion or dizziness.

What causes double vision (diplopia)?

Double vision is often a symptom of other health conditions. We've divided them into the following groups.

Problems in the eye

Diplopia can be a symptom of a few different eye conditions which may affect the cornea (the clear part on the front of your eye) or the lens (which helps focus light onto the retina at the back of your eye). Eye problems that can cause double vision include astigmatism, cataracts, dry eye syndrome, glaucoma and macular degeneration.

Problems with the eye muscles 

If the muscles that move your eyes aren’t working together, it can lead to double vision. This can be caused by conditions like Graves' disease, myasthenia gravis, head injuries or squint (strabismus).

Problems with your nerves 

Problems with the nerves linking your eyes and brain can cause double vision. This can happen with conditions like cranial nerve palsy, multiple sclerosis, Guillain‑Barré syndrome, or diabetes.

Problems in the brain 

Double vision can be linked to strokes, tumours, aneurysms, injuries, or infections in the brain, all of which need urgent care. It can also affect people with migraine headaches.

Problems with glasses or contact lenses 

Double vision can happen if your contact lenses or glasses prescription aren't quite right.

Problems caused by other medication 

Double vision may be a side effect of certain medicines ‑ let your GP or pharmacist know if this happens to you.

Other health conditions 

Several other health conditions can also cause double vision including Wernicke's syndrome, Lyme disease, and some kinds of cancer.

Problems caused by lifestyle 

Certain lifestyle factors, such as drinking too much alcohol or consuming other intoxicants can cause double vision. It can also happen when you're extremely tired.

How is double vision diagnosed?

Because diplopia can be caused by many different things, your doctor or optometrist will use a range of methods to identify the cause. Double vision tests include the following techniques.

Medical history 

Your optometrist will ask when it started, what you’re seeing, what medication you take, and if symptoms follow a pattern or happen during certain activities.

Eye examinations 

At our stores in Australia, optometrists may use tests like OCT scans, slit lamp test, and dilated eye exams, among others.  
Learn more about eye tests.

Blood tests 

Blood tests might be used to check for a variety of illnesses, including cancers, immune system disorders and neurological conditions.

Imaging scans 

You may be referred for imaging scans (such as MRI or CT scans) which help build a picture of what's happening inside your brain.

How is double vision treated?

The right treatment for diplopia depends on what’s causing it. For example, if it’s due to an eye condition like strabismus, corrective glasses may be all that’s needed. But if it’s linked to something like multiple sclerosis, you might need to take medications, have physio and make lifestyle changes. 
 
Below, we’ve listed some common ways to manage the double vision itself. However, if another condition is the underlying cause, you’ll need treatment that focuses on addressing that root cause.

Prism lenses 

Prism lenses are layers that can be stuck onto your normal glasses (Fresnel Prism) or even built into the lens. If your diplopia is caused by problems with eye alignment, the prism bends light to shift the image of the object, correcting the double vision.

Blocking vision in one eye 

Diplopia might be due to a weakness in one eye. Your optometrist might recommend blocking vision in your healthy eye, forcing the weaker eye to work harder and improving your vision over time.

Injections with Botox 

Botulinum toxin (Botox) injections can help by relaxing the muscles in the stronger eye. This gives the weaker eye a chance to recover and realign.

Surgery for double vision 

Surgery may be recommended by your optometrist if muscle weakness or eye conditions like cataracts or keratoconus are causing double vision. It might also be used to treat a droopy eyelid.

Referral to specialists 

If your GP or optometrist suspects that another health issue ‑ such as a brain tumour, diabetes or hormonal disorder ‑ is causing your double vision, they’ll refer you to a relevant specialist for further investigation and treatment.