Floaters and flashes: when they are harmless, and when they are urgent
Small specks, threads or cobwebs drifting across your vision are floaters. Most are harmless clumps in the eye's gel. But a sudden shower of new floaters, flashes of light, or a shadow at the edge of vision can mean a retinal tear, which needs to be seen the same day.
Medically reviewed by Dr. Ananyabrata Das, MBBS, DOUpdated 22 October 2026
What causes them
The inside of the eye is filled with a clear gel called the vitreous. With age, and earlier in people with high short-sight (minus power), it turns watery and shrinks. Clumps in it cast shadows on the retina: those are floaters. When the gel pulls away from the retina (a posterior vitreous detachment), it can tug the retina, which you see as flashes of light, often at the side of vision and in the dark.
Get checked the same day if
- Floaters appear suddenly, or there are many new ones at once
- You see flashes of light
- A shadow, curtain or veil spreads from one side
- You are short-sighted, have had cataract surgery, or an eye injury
Treatment
If the retina is intact, most floaters need no treatment: the brain learns to ignore them over weeks to months. A tear is sealed with laser. A detachment needs surgery. See retina care.
Questions
Will floaters go away?
They rarely vanish, but most become far less noticeable within a few months.
Are floaters a sign of a serious problem?
Usually not. Sudden new floaters with flashes or a shadow can mean a retinal tear and need a same-day check.