Symptom
Flashes and floaters
A sudden increase is an emergency
Clinically reviewed · Last reviewed 2026-06-13
When to get urgent help
- A sudden increase in floaters, like a shower of spots
- New or repeated flashes of light
- A dark shadow or curtain spreading across your vision
- A sudden drop in vision
Common causes
Flashes and floaters relate to the back of the eye. These are the key conditions to read about next.
Floaters and flashes Usually harmless, age-related changes in the eye's gel. Posterior vitreous detachment When the gel separates from the retina; common with age and often causes new floaters and flashes. Retinal tear A tear in the retina can cause a sudden increase in floaters and flashes before detachment. Retinal detachment A sudden increase with a shadow is an emergency needing same-day care. Vitreous haemorrhage Bleeding into the gel can cause a sudden shower of dark floaters and reduced vision. Lattice degeneration Thinning at the retina edge increases tear risk, especially with new floaters.
What can help
- Stable, long-standing floaters usually need no treatment
- Treat any sudden change as an emergency
- Have an eye test if floaters bother you or change
Frequently asked questions
Are flashes and floaters serious?
Occasional floaters are usually harmless, but a sudden increase in floaters or flashes, or a shadow over your vision, needs same-day assessment to rule out retinal detachment.
What causes flashes of light in the eye?
Flashes often happen when the eye's gel tugs on the retina. New or repeated flashes should be checked promptly.
Do floaters go away?
Long-standing floaters often become less noticeable over time. A sudden change, however, should be assessed urgently.