Blurred vision means things look out of focus or hazy. It can come on slowly or suddenly, and affect one eye or both. Often the cause is simple, such as needing glasses or a new prescription, but it can also be a sign of an eye condition that needs treatment.
The NHS says to see an optician if you think your vision is getting worse. Sudden blurred vision needs urgent advice, and sudden loss of sight in one or both eyes is an emergency.
When it is urgent
The NHS advises asking for an urgent GP appointment or getting help from NHS 111 if you have:
- Changes in your vision, such as blurred vision, double vision, or seeing flashing lights or shapes
- A dark shadow moving across your vision
- Pain in one or both eyes
- A red and painful eye
- Eyes that feel painful or uncomfortable in bright light
When to go to A&E
Go to A&E or call 999 if you suddenly cannot see from one or both eyes, or suddenly have severe eye pain. Do not drive yourself. Ask someone to take you, or call 999.
Possible causes
The NHS lists these as common causes of changes in vision. Your symptoms can give a clue, but only an eye examination can tell for sure.
| What you notice | Possible cause |
|---|---|
| Blurred or cloudy vision, halos around lights, colours looking less bright | Cataracts |
| A distorted area in the middle of your vision, difficulty reading or seeing faces | Age-related macular degeneration (AMD) |
| Gradual worsening of sight if you have diabetes | Diabetic retinopathy |
| Blurred vision with severe eye pain and a red eye | Glaucoma |
| Dots, lines, flashes or a shadow appearing suddenly | Detached retina |
| Sore, blurry or watery eyes | Dry eyes |
Blurred vision and your glasses
Blurred vision is often a sign that you need glasses or that your prescription has changed. Short sight blurs things in the distance, long sight and presbyopia blur things close up, and astigmatism can blur things at any distance. An eye test checks your prescription and the health of your eyes at the same time.
Driving
You must be able to meet the legal eyesight standard for driving, with glasses or contact lenses if you need them. If your vision has become blurred, do not drive until you have had your eyes checked.
Sources
Last checked: 12 November 2026
