Floaters are small shadows that drift across your vision: dots, threads or cobwebs that move when your eye moves. Flashes are brief sparks or streaks of light, often noticed at the edge of vision or in the dark.
Why they happen
The inside of the eye is filled with a clear gel called the vitreous. With age the gel becomes more liquid and eventually separates from the retina. This separation, called posterior vitreous detachment, is common and often causes new floaters and flashes. In most people it is harmless.
Sometimes the gel pulls hard enough on the retina to tear it. Fluid can then pass through the tear and lift the retina away from the back of the eye. This is a retinal detachment.
Warning signs that need same-day care
- A sudden shower of new floaters
- New flashes of light
- A shadow or curtain spreading across part of your vision
- A sudden drop in vision
These symptoms need a dilated examination of the whole retina on the same day. If you are abroad or travelling, go to the nearest eye emergency service and do not wait until you return.
Who is at higher risk
The risk of a retinal tear is higher with high myopia, previous eye surgery such as cataract surgery, eye injury, a previous retinal tear or detachment, and a family history of retinal detachment.
What happens next
If no tear is found, you may be asked to return for a check-up and to come back straight away if your symptoms change. A tear found early can often be treated with laser or freezing treatment, which lowers the risk of detachment.
Information on this website is educational and does not replace an in-person medical examination, diagnosis or individual medical advice.