Eyes
Double vision
Seeing two images of a single object — a symptom that can come from the eye muscles, the nerves controlling them or the brain, and which when it starts suddenly may be a sign of a stroke and needs emergency assessment.
Education and reference only. This explains the common causes of double vision and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is double vision?
Double vision, or diplopia, means a single object appears as two. It is important to notice whether the doubling disappears when one eye is covered: double vision that vanishes with either eye covered (binocular) comes from the two eyes not pointing in exactly the same direction, usually because of a problem with the eye muscles or the nerves that control them; double vision that persists in one eye even when the other is shut (monocular) usually comes from a problem within that eye itself, such as a cataract or dry eye.
- Get urgent help: Call 999 immediately if double vision comes on suddenly, or with face drooping, arm weakness or slurred speech — think FAST, this may be a stroke. Call 999 for double vision with a sudden, severe headache, a stiff neck, confusion or a fit.
- Self-care: New double vision is not a symptom to manage at home — it should be assessed to find the cause.
About double vision
Double vision, or diplopia, means a single object appears as two. It is important to notice whether the doubling disappears when one eye is covered: double vision that vanishes with either eye covered (binocular) comes from the two eyes not pointing in exactly the same direction, usually because of a problem with the eye muscles or the nerves that control them; double vision that persists in one eye even when the other is shut (monocular) usually comes from a problem within that eye itself, such as a cataract or dry eye. Sudden-onset binocular double vision is the one that demands urgency, because it can be caused by a stroke, particularly when it appears alongside other warning signs such as weakness, slurred speech, a drooping face or a severe headache. Double vision that fluctuates through the day, worsening with tiredness, can point to a problem at the junction between nerve and muscle. Any new double vision should be assessed promptly.
When to get help
Call 999 or go to A&E if double vision comes with any of these warning signs:
- Call 999 immediately if double vision comes on suddenly, or with face drooping, arm weakness or slurred speech — think FAST, this may be a stroke.
- Call 999 for double vision with a sudden, severe headache, a stiff neck, confusion or a fit.
- Seek urgent same-day help for double vision with severe eye pain, a red eye, or loss of vision.
- Seek urgent help for double vision after a head injury, or with new weakness, numbness or difficulty walking or speaking.
- See a doctor urgently for double vision that fluctuates and is accompanied by drooping eyelids or difficulty swallowing or breathing.
When to see a doctor
Treat sudden double vision as an emergency and call 999, especially if it comes with any weakness, slurred speech, a drooping face, a severe headache or after a head injury, because a stroke must be ruled out quickly. Seek urgent same-day help for double vision with eye pain, a red eye or loss of vision. Even double vision that comes and goes, or that worsens when you are tired, should be assessed urgently rather than ignored. If a clinician has already investigated a long-standing, stable cause, attend your follow-up and seek advice if anything changes or worsens.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of double vision
Double vision has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
New double vision is not a symptom to manage at home — it should be assessed to find the cause. If a clinician has already explained a stable, long-standing reason for your double vision, they may suggest practical measures such as covering one eye to remove the second image when needed, taking care on stairs and not driving until you have been advised it is safe. Rest your eyes when tired if fatigue makes it worse, and attend any follow-up appointments so the cause can be monitored. The most useful thing you can do with new double vision is to note whether it goes away when you cover one eye and to seek assessment quickly, as this guides whether it is an emergency.
Answers
Double vision: frequently asked questions
Is sudden double vision a stroke?
It can be. Sudden double vision, especially with weakness, slurred speech, a drooping face or a severe headache, may be a stroke. Use the FAST test and call 999 immediately — do not wait to see if it settles.
What does it mean if covering one eye fixes it?
If the double vision disappears when you cover either eye, it comes from the two eyes not aligning, usually a muscle or nerve problem. If it remains in one eye when the other is covered, the issue is within that eye. Either way, new double vision needs assessment.
Can tiredness cause double vision?
Double vision that worsens with tiredness through the day can point to a problem at the junction between nerve and muscle, such as myasthenia gravis. This should be assessed urgently, particularly if eyelids droop or swallowing or breathing is affected.
Should I drive with double vision?
No. Double vision affects your judgement of distance and is dangerous when driving. Do not drive until a clinician has assessed you and advised it is safe, and seek emergency help if the double vision is sudden.
Sources
Where this is drawn from
- NICE CKS: Stroke and TIA.
- Royal College of Ophthalmologists: double vision.
Related symptoms
Tell us what you need. We'll route it to the right expert.
Request a proposal, book a scoping call, or speak to our team directly.