- Home
- Knowledge centre
- Eye conditions & symptoms A–Z
- Diplopia (Double Vision): Causes and Urgent Signs
Diplopia (Double Vision): Causes and Urgent Signs
Diplopia, or double vision, means seeing two images of one object. If it disappears when you cover one eye, the cause is usually in the eye itself, such as dry eye, astigmatism, a cataract or keratoconus. If it only disappears when either eye is covered, the eyes are not working together, which can mean a squint or a problem with the eye muscles, nerves or brain. Sudden double vision, eye pain, a severe headache or a head injury needs urgent medical care. Squint surgery by Prof. Dr. Ahmet Satıcı is an option for suitable, stable cases.
What is diplopia?
Diplopia is the medical word for double vision: seeing two images of a single object. The American Academy of Ophthalmology (AAO) describes it as seeing two, often overlapping, images. The two pictures can sit side by side, one above the other, or at a slant. They can be there all the time, or come and go.
The NHS stresses that double vision is not usually serious but is important to get checked, even if it comes and goes. The reason is simple: double vision is a symptom, not a disease. Behind it can be anything from a dry surface on the eye to a nerve problem that needs treatment the same day. Finding out which, and how fast, is the whole point of this guide.
Is your double vision in one eye or both eyes?
Cover one eye at a time. This is the first test the NHS suggests: try covering one eye at a time to see if the double vision goes away.
| What happens | Name | What it usually means |
|---|---|---|
| The double image stays when the other eye is covered | Monocular diplopia (one eye) | A problem inside that eye: the tear film, cornea or lens |
| The double image goes away when either eye is covered | Binocular diplopia (both eyes) | The two eyes are not pointing at the same place: a squint, or a problem with the eye muscles, the nerves that move them, or the brain |
Always tell your optician or doctor which pattern you have. It is the most useful single piece of information you can give them, and it sorts the possible causes into two very different lists.
What causes double vision in one eye (monocular diplopia)?
Monocular diplopia is usually an eye-surface or lens problem, not a brain problem. The NHS lists four causes:
- Dry eyes. Not enough tears leave an uneven surface that scatters light, so a point of light can split or ghost.
- Astigmatism. The front of the eye has an imperfect shape, so light is not focused to a single point.
- Cataracts. The lens clouds. The AAO lists "seeing double or a ghosted image out of the eye with a cataract" among cataract symptoms. Cataracts can be removed only by surgery, in which the cloudy lens is replaced by a clear artificial lens.
- Keratoconus. The cornea thins and changes shape, distorting the image.
The AAO also lists complications after LASIK among the conditions linked with double vision, and the US Food and Drug Administration (FDA) notes that some patients develop glare, halos or double vision after LASIK that can affect night vision. If you have had laser eye surgery and notice a ghost image, tell your surgeon.
Who treats these at Laser Istanbul Clinic. Cataract and lens surgery is performed by Prof. Dr. Ahmet Satıcı, Doç. Dr. Muhammet Derda Özer (Doç. means Associate Professor) or Op. Dr. Aysan Bayram. Keratoconus, including cross-linking, is the field of Doç. Dr. Muhammet Derda Özer.
What causes double vision in both eyes (binocular diplopia)?
Binocular diplopia is a problem of eye alignment. Each eye is moved by small muscles that are controlled by nerves running from the brain. If a muscle, a nerve or the brain's control of them is affected, the eyes stop lining up. The NHS says binocular double vision usually means a squint, and that in adults a squint or binocular double vision can be a sign of a more serious condition.
Children usually do not complain of double vision when an eye turns, because the brain learns to ignore the image from the misaligned eye. The AAO explains that adults who develop strabismus later cannot do this, because their brains are used to using both eyes, so they see two images.
The main groups of causes are:
| Group | Examples | What to know |
|---|---|---|
| Nerve palsy (the nerve to an eye muscle is not working) | Microvascular cranial nerve palsy; nerve damage after injury | Microvascular palsy is linked with older age, diabetes, high blood pressure and smoking; the AAO says it almost always gets better on its own in about 6 to 12 weeks |
| Muscle or nerve-to-muscle disease | Myasthenia gravis; thyroid eye disease | The AAO says myasthenia often starts in the eyes, with a droopy eyelid or double vision |
| Pressure or disease inside the head | Idiopathic intracranial hypertension (raised pressure around the brain); brain tumour; aneurysm | Needs urgent imaging and specialist care |
| Blood-vessel and inflammatory disease | Stroke; giant cell arteritis | Emergencies: see "Urgent signs" below |
| Injury | Head injury; injury around the eye | Seek emergency care after a head injury |
| An existing squint | Strabismus in adults | Can be treated: see "Treatment" below |
What is the most common cause of double vision?
There is no single answer, because it depends on age, on whether it is monocular or binocular, and on where the patient was seen. In a hospital series of 303 adults with binocular diplopia at a tertiary eye centre in south China, published in Frontiers in Neurology in 2021, the causes were:
| Cause | Share of 303 patients |
|---|---|
| Trauma | 23.1% (70 patients) |
| Thyroid eye disease (thyroid-associated ophthalmopathy) | 19.1% (58) |
| No cause found (idiopathic) | 16.5% (50) |
| Microangiopathy (damage to the tiny blood vessels that supply the nerves) | 16.2% (49) |
| Lesions inside the brain | 9.2% (28) |
| Myasthenia gravis | 4.6% (14) |
When only one eye muscle was affected, microangiopathy (26.6%) and trauma (25.9%) were the most frequent causes. These figures come from one centre's patients seen between 2012 and 2014, so they show the range of causes more than a rule for every country. For double vision in one eye, the NHS gives a list, not a ranking: dry eye, astigmatism, cataract and keratoconus.
What causes sudden or temporary double vision?
Sudden double vision should be treated as urgent until proven otherwise, even if it goes away. The NHS advises calling 111 or getting an urgent GP appointment for sudden double vision or double vision with eye pain, and going to A&E or calling 999 for double vision with a severe headache or a dilated pupil, or after a head injury.
Reasons for double vision that comes and goes include:
- Migraine. The AAO lists migraine among the conditions linked with double vision.
- Myasthenia gravis. The AAO describes weakness that fluctuates between symptomatic and symptom-free periods. Drooping eyelids are the most common first sign.
- A stroke or transient ischaemic attack (mini-stroke). The NHS lists vision problems among stroke symptoms and says to call 999 if you think you have had a stroke, or had stroke symptoms in the past 24 hours, even if they have gone, because symptoms can be temporary but still need urgent evaluation.
- Dry eyes. The NHS lists dry eye as a cause of double vision in one eye.
If the double vision has already gone, you still need to be seen quickly. Do not wait for it to come back.
What causes double vision in the elderly?
In older adults, vascular and inflammatory causes need to be ruled out first. After age 50, an eye specialist will think of the following:
- Microvascular cranial nerve palsy. The AAO lists older age, diabetes, high blood pressure and smoking as risk factors. Symptoms are double vision, often with the images stacked vertically, a drooping eyelid, or eye pain that can come before the double vision. It usually recovers in about 6 to 12 weeks; blood pressure and blood sugar are managed in the meantime.
- Giant cell arteritis. The AAO says it mainly affects people over 50, with a peak around age 70, and that women are twice as likely as men to have it. Its eye symptoms are sudden painless vision loss and double vision, often with severe headaches, scalp tenderness around the temples and jaw cramps when chewing. The AAO calls it "extremely important" to be checked by an ophthalmologist right away, because blindness in one eye can follow and then affect the other eye without treatment. Treatment is steroid tablets, sometimes started before the diagnosis is confirmed.
- Stroke and brain-blood-vessel disease. See "Urgent signs" below.
- Cataract. Listed by the AAO as a cause of a ghosted or double image in the affected eye, and treated by surgery.
- Myasthenia gravis and thyroid eye disease, which also cause double vision from the eye muscles.
Urgent signs: when is double vision an emergency?
Treat double vision as an emergency if any of these apply:
| What you notice | What the NHS or AAO advises |
|---|---|
| Sudden double vision | Call 111 or get an urgent GP appointment (UK). Do not wait to see if it settles |
| Double vision with eye pain | Call 111 or get an urgent GP appointment (UK) |
| Double vision with a severe headache, or a dilated pupil | Call 999 or go to A&E (UK) |
| Double vision after a head injury | Call 999 or go to A&E (UK) |
| Face drooping, arm weakness or numbness, slurred speech | Call 999 (FAST stroke signs). Do not drive yourself |
| Sudden, severe "thunderclap" headache | Call 999. The NHS names this as the main sign of a burst brain aneurysm |
| Pain above or around the eye, headache and double vision | The NHS lists these as symptoms of a larger unruptured aneurysm; call 111 or see a doctor urgently |
| Double vision with temple headache, scalp tenderness, jaw pain when chewing, or vision loss | Possible giant cell arteritis: ask for an urgent GP appointment or call 111 (NHS); an ophthalmologist should see you right away (AAO) |
| Droopy eyelid, double vision and difficulty breathing | Possible myasthenic crisis: emergency care. The AAO calls it life-threatening when breathing muscles are affected |
Outside the UK, use your local emergency number and the nearest emergency department. Do not delay for a flight, an appointment abroad or a call to a clinic. If you are in Istanbul and notice any of these signs, tell your coordinator at once and go to the nearest emergency department.
How is the cause of double vision found?
Diagnosis starts with your story and a simple cover test, then moves to eye and nerve examination. According to the NHS, an optician or GP will ask about your symptoms and do simple, painless eye tests, and may refer you to a hospital eye specialist for further tests and treatment. Expect questions about when it started, whether it is constant, whether it is in one eye or both, and whether you have other symptoms such as headache, a droopy lid, weakness or tiredness.
The specialist then typically checks how well the eyes move, measures how far they are misaligned, examines the surface, lens and back of the eye, and decides whether blood tests or brain scans are needed. For myasthenia gravis, the AAO lists blood tests, a neurological examination and nerve stimulation tests.
Useful things to bring or record: a short phone video of how the eyes move, the time the double vision started, your medicines, and any scans you already have. If you want our eye team's view on existing results, you can upload them through the free consultation.
If you also have general symptoms such as tiredness, our guides on iron deficiency and your eyes and vitamin B12 deficiency: eye symptoms explain what blood tests can look at.
What is the treatment for double vision?
Treatment depends entirely on the cause, so the first step is always to find it. According to the NHS, it may include eye exercises, eye patches, glasses or contact lenses, or eye surgery. In practice:
| Option | What it is | Typical use |
|---|---|---|
| Treat the cause | Cataract surgery; steroids for giant cell arteritis; medicines for myasthenia gravis; weight loss and acetazolamide for idiopathic intracranial hypertension; blood pressure and blood sugar control for a microvascular palsy | The first step when a cause is found |
| Patching | A patch over one eye removes the second image | Short-term relief while a nerve recovers |
| Prism glasses | The AAO describes a prism as a clear, wedge-shaped lens that bends light rays, helping people with mild double vision see one image | Mild double vision |
| Vision therapy | Eye-muscle exercises | The AAO mentions it for convergence insufficiency, mainly for near tasks |
| Botulinum toxin injection | An injection weakens a misaligned muscle. The NHS says the effect lasts less than 3 months | Temporary improvement in alignment |
| Squint (strabismus) surgery | The surgeon loosens, tightens or repositions eye muscles | When glasses, prisms or other measures are not enough |
Squint surgery for adults. The AAO says strabismus surgery is an outpatient procedure under general or local anaesthesia with recovery within days, that more than one operation may be needed, and that treatment is available at any age. Our page on Strabismus (squint) surgery for adults & children explains how the operation is done, who it suits and what to expect. In Istanbul it is performed by Prof. Dr. Ahmet Satıcı.
When is surgery considered? Not during the first emergency work-up. Surgery is for people in whom the cause is known, any underlying illness is under control and the double vision has stopped changing. The surgeon decides when that point has been reached ({{how long double vision must be stable before squint surgery, per Prof. Dr. Satıcı}}).
Can I drive with double vision?
No, not until a doctor has cleared you. The NHS says you must stop driving and tell the DVLA once double vision is diagnosed, and only restart when a doctor says it is safe. The GOV.UK driving standards list diplopia among the eye conditions to report, with "no double vision" part of the visual standard. Other countries have their own rules, so ask your doctor. It is sensible to avoid cycling, ladders and machinery while you see double.
Frequently asked questions
Usually a problem inside that eye. The NHS lists dry eyes, astigmatism, cataracts and keratoconus. If the double image stays when you cover the other eye, tell your optician; an eye test can tell these causes apart.
Often, yes. Binocular double vision means the eyes are not aligned, which can come from eye muscles, nerves or the brain. The NHS says that in adults it can be a sign of a more serious condition, so it should always be checked.
Possible causes include migraine, myasthenia gravis and a mini-stroke. Because a mini-stroke can look like this, get checked even if the double vision has gone. The NHS says to call 999 if stroke symptoms occurred in the last 24 hours, even if they have resolved.
It depends on the type and the patient. In one series of 303 adults with binocular diplopia, trauma (23.1%) was the most frequent cause, followed by thyroid eye disease (19.1%). For one-eye double vision, the NHS names dry eyes, astigmatism, cataracts and keratoconus.
Common causes are microvascular nerve palsy (linked with diabetes, high blood pressure, smoking and older age), giant cell arteritis, stroke and cataract. Sudden double vision at any age needs a prompt check.
Sometimes. The AAO says a microvascular cranial nerve palsy almost always improves on its own in about 6 to 12 weeks. Many other causes will not, and you cannot tell which kind you have without an examination.
It depends on the cause. Options range from cataract surgery, patches and prism glasses to medicines for conditions such as myasthenia gravis, and squint surgery for suitable cases.
Yes, in selected cases. If the cause is an eye-muscle misalignment, strabismus surgery can realign the eyes, and cataract surgery treats double vision caused by a cataract. Your surgeon will explain whether either applies to you.
Some night-vision disturbance is common in the first weeks, but the FDA notes that a small number of patients develop lasting glare, halos or double vision. Tell your surgeon if you see double after laser surgery.
Double vision from a squint or eye-muscle problem?
If your double vision has been investigated and is caused by eye misalignment, Prof. Dr. Ahmet Satıcı at Laser Istanbul Clinic can assess whether squint surgery is suitable. Surgery takes place in a fully equipped, Ministry of Health–licensed operating theatre in Istanbul. If a cause outside the eye is suspected, we will tell you honestly and advise you to see a neurologist or your own doctor first.
Sources for the facts on this page
- NHS. Double vision. https://www.nhs.uk/conditions/double-vision/
- NHS. Squint. https://www.nhs.uk/conditions/squint/
- NHS. Stroke: symptoms. https://www.nhs.uk/conditions/stroke/symptoms/
- NHS. Brain aneurysm. https://www.nhs.uk/conditions/brain-aneurysm/
- NHS. Temporal arteritis (giant cell arteritis). https://www.nhs.uk/conditions/giant-cell-arteritis/
- American Academy of Ophthalmology. Double vision (symptom page). https://www.aao.org/eye-health/symptoms/double-vision
- American Academy of Ophthalmology. What is adult strabismus? https://www.aao.org/eye-health/diseases/what-is-strabismus
- American Academy of Ophthalmology. Microvascular cranial nerve palsy. https://www.aao.org/eye-health/diseases/microvascular-cranial-nerve-palsy
- American Academy of Ophthalmology. Giant cell arteritis. https://www.aao.org/eye-health/diseases/giant-cell-arteritis
- American Academy of Ophthalmology. Myasthenia gravis. https://www.aao.org/eye-health/diseases/myasthenia-gravis
- American Academy of Ophthalmology. Idiopathic intracranial hypertension. https://www.aao.org/eye-health/diseases/idiopathic-intracranial-hypertension
- American Academy of Ophthalmology. What are cataracts? https://www.aao.org/eye-health/diseases/what-are-cataracts
- Wang et al. Etiology and Clinical Features of Diplopia in South China: Analysis of 303 Cases. Frontiers in Neurology 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8889929/
- US Food and Drug Administration. LASIK: What are the risks and how can I find the right doctor for me? https://www.fda.gov/medical-devices/lasik/what-are-risks-and-how-can-i-find-right-doctor-me
- GOV.UK (DVLA). Diplopia (double vision) and driving. https://www.gov.uk/diplopia-and-driving