Eyes
Floaters and flashing lights
Small specks, threads or cobwebs that drift across your vision, sometimes with brief flashes of light — usually a harmless age-related change in the jelly inside the eye, but a sudden shower of new floaters, flashes or a shadow across vision can mean a retinal detachment needing same-day care.
Education and reference only. This explains the common causes of floaters and flashing lights 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 floaters and flashing lights?
Floaters are small shapes — dots, threads, cobwebs or rings — that drift across the field of vision and move as the eyes move, often most obvious against a bright, plain background such as the sky or a white wall. They are caused by tiny clumps within the clear jelly that fills the eye casting shadows on the retina at the back.
- Get urgent help: Seek same-day eye assessment, at an eye casualty or A&E, for a sudden shower of new floaters or a sudden increase in their number. Seek same-day help for new or worsening flashing lights in your vision.
- Self-care: For long-standing floaters that have already been checked and found to be harmless, there is no treatment needed and they usually become less noticeable over time as the brain adapts to them.
About floaters and flashing lights
Floaters are small shapes — dots, threads, cobwebs or rings — that drift across the field of vision and move as the eyes move, often most obvious against a bright, plain background such as the sky or a white wall. They are caused by tiny clumps within the clear jelly that fills the eye casting shadows on the retina at the back. Most floaters are a normal part of ageing as this jelly shrinks and pulls away from the retina, and once the brain learns to ignore them they become less troublesome. Brief flashes of light can occur as the jelly tugs on the retina. The crucial point is the difference between long-standing, stable floaters and a sudden change: a new shower of many floaters, new or increasing flashing lights, or a dark curtain or shadow spreading across part of the vision can mean the retina is tearing or detaching, which threatens sight and is an eye emergency requiring same-day assessment.
When to get help
Call 999 or go to A&E if floaters and flashing lights comes with any of these warning signs:
- Seek same-day eye assessment, at an eye casualty or A&E, for a sudden shower of new floaters or a sudden increase in their number.
- Seek same-day help for new or worsening flashing lights in your vision.
- Seek same-day help if a dark curtain, shadow or veil spreads across part of your vision — this can mean the retina is detaching.
- Seek urgent help if floaters come with eye pain, redness or a sudden loss or blurring of part of your sight.
- Get checked promptly if you have diabetes and notice new floaters, which can indicate bleeding at the back of the eye.
When to see a doctor
A few stable floaters that you have had for a long time and that do not change are usually harmless and do not need urgent attention, though it is sensible to have them checked at a routine eye test. The vital message is to act fast for any sudden change: a sudden shower of new floaters, new or increasing flashes of light, or a shadow or curtain moving across your vision needs same-day assessment by an eye specialist, an eye casualty service or A&E, because prompt treatment of a tearing or detaching retina can save your sight. Floaters with eye pain, redness or visual loss also need urgent review.
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 floaters and flashing lights
Floaters and flashing lights 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
For long-standing floaters that have already been checked and found to be harmless, there is no treatment needed and they usually become less noticeable over time as the brain adapts to them. Good lighting when reading and moving your eyes up and down or side to side can shift a floater out of your direct line of sight when it is bothersome. The single most important piece of self-care is knowing the warning signs: any sudden increase in floaters, new flashing lights, or a curtain or shadow over part of your vision is not something to watch and wait on — it needs same-day eye assessment. If you have diabetes, keeping it well controlled and attending your eye screening appointments protects the back of your eyes.
Answers
Floaters and flashing lights: frequently asked questions
Are floaters dangerous?
Most floaters are a harmless part of ageing. The danger sign is a sudden change — a shower of new floaters, new flashing lights, or a shadow across your vision — which can mean a retinal detachment and needs same-day assessment.
What causes flashing lights in my vision?
Flashes often occur when the jelly inside the eye tugs on the retina. Occasional brief flashes can be harmless, but new or increasing flashes, especially with new floaters or a shadow, need urgent eye assessment.
When should I get floaters checked the same day?
Seek same-day eye care if you suddenly see many new floaters, new or worsening flashes of light, or a dark curtain or shadow over part of your vision, as these can signal a detaching retina that threatens sight.
Do floaters go away?
Harmless floaters often become less noticeable over time as the brain learns to ignore them, even if they do not fully disappear. Any sudden new floaters, however, should be assessed urgently before assuming they are harmless.
Sources
Where this is drawn from
- NICE CKS: Retinal detachment.
- Royal College of Ophthalmologists: floaters and flashes.
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