About this symptom
Blurred vision means things look out of focus, hazy or cloudy. It can affect one eye or both, and it can come on suddenly or slowly.
Many causes are simple, such as needing glasses or a new prescription, and are easily put right. But blurred vision can also be a sign of a serious problem in the eye or the brain, and several of these can be treated only within a short time. That is why how fast it came on, and what else comes with it, matter so much.
Possible causes
This is not a diagnosis. These are the causes doctors think about, with the ones that are most urgent to rule out first.
- StrokeSudden blurred or double vision, or loss of sight in one or both eyes, even if it passes. A drooping face, a weak arm or slurred speech with it is an emergency.Read about it
- Retinal detachmentFlashes of light, a sudden increase in floaters, or a dark shadow or curtain across your sight. An emergency: delay can raise the risk of permanent sight loss.
- GlaucomaSlowly developing glaucoma can narrow your sight into tunnel vision. A sudden attack, with a red, painful eye and blurred vision, is an emergency.Read about it
- Diabetic retinopathyDiabetes can damage the eye's blood vessels. There are often no symptoms early on. Later: blurring, shadows or missing areas, and dark floating spots or streaks.Read about it
- CataractCloudy or fuzzy vision that builds up slowly, with glare and halos around lights, because the lens of the eye has become cloudy.Read about it
- MigraineSpots of light, halos or zigzag patterns before a headache. A first episode still needs to be checked.Read about it
- Needing glassesBlurred vision for near or distant objects. From the early to mid-40s, trouble focusing on close objects is common. An eye test finds out.
- Side effect of a medicineSome medicines can affect vision. Do not stop or change a medicine on your own: ask the doctor who prescribed it.
When to get help
Also get emergency care for:
- Blurred vision with a drooping face, a weak arm or slurred speech: call for an ambulance
- Blurred vision with a severe headache or confusion
- Blurred vision after an injury to the eye
See a doctor soon if you have:
- Blurring that has built up gradually over weeks or months
- Trouble reading, or trouble seeing things near or far
- Trouble seeing at night, or glare and halos around lights that have built up slowly
- Diabetes, and your eyes have not been checked recently
- Blurring that began after you started a new medicine
- Blurred vision with itching or discharge from the eye
Not having pain does not make it safe to wait, because serious vision loss is often painless. Mild, steady blurring with no sudden change can wait for an eye test in the next few days.
What you can do at home
If any emergency sign is present, do not try anything at home: go for eye care straight away. For slow, mild blurring, a few simple steps help the doctor.
Do
- Cover each eye in turn to see which eye is affected
- Note when it began and anything else that came with it
- Take your glasses and a list of your medicines to the eye test
- If you have diabetes or high , keep your checks up to date
Do not
- Do not wait to see whether sudden blurring clears up
- Do not drive or use machinery if your vision is not clear
- Do not stop or change a medicine on your own, even if you think it is the cause
- Do not rub the eye or put drops in it without advice
What the doctor will do
The doctor will ask which eye is affected, how and when the blurring began, and whether there is pain, flashes, floaters, double vision, light sensitivity or headache. They will ask about earlier eye problems, medicines, diabetes, and eye disease in the family.
They will check your vision, eye movements, pupils and the back of the eye. Tests may include:
- A refraction test, to see whether glasses will help
- A dilated eye exam, with drops that widen the pupil
- An eye pressure test (tonometry) and a close look at the eye with a slit lamp
- Checks of blood sugar and blood pressure, if diabetes or high blood pressure may be involved
Treatment depends on the cause, and some conditions need surgery. A suspected stroke is treated as an emergency in hospital.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“If it does not hurt, it is not serious.”What is true?
Fact
Most serious forms of vision loss are painless. Sudden blurring or loss of sight needs urgent care whether or not the eye hurts, because many causes can be treated only within a short time.
Myth“My sight came back, so it was nothing.”What is true?
Fact
Partial or complete loss of sight needs emergency care even if it is brief. A short episode can be a warning of a stroke or another serious problem, so get checked the same day.
Myth“Blurred vision is just part of getting older.”What is true?
Fact
Trouble focusing on close objects is common from the early to mid-40s, and glasses help. But cataract, glaucoma, diabetic eye disease and other conditions can also affect sight, so an eye test is worth having rather than assuming.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
How do I know whether my blurred vision is an emergency?
Think about how fast it came on and what came with it. Sudden loss of vision, double vision, a curtain or shadow across your sight, flashes of light, or blurring with eye pain, a severe headache or a drooping face needs emergency care. Slow blurring can usually wait for an eye test in the next few days.
Can diabetes cause blurred vision?
Yes. Diabetes can damage the blood vessels at the back of the eye, which can cause blurring, shadows or missing areas in your sight. It often causes no symptoms at first, so people with diabetes need regular eye exams, with drops to widen the pupils, to catch it early.
Can a stroke cause blurred vision?
Yes. Blurred vision or loss of sight in one or both eyes can be a sign of a stroke, along with a drooping face, a weak arm or slurred speech. The symptoms can stop after a short time, but you should still get medical help straight away.
Will I need glasses?
If the blurring is for near or distant objects and there are no warning signs, glasses are a common answer. An eye test will find out. Trouble focusing on close objects is common from the early to mid-40s, and glasses can help.
