Eye floaters are small shapes that drift across your vision — they may appear as dots, threads, cobwebs, or squiggly lines. Most people notice them when looking at a plain bright background such as a white wall or blue sky. They move as you move your eyes and tend to drift away when you try to look directly at them.
Most floaters are harmless and are caused by natural age-related changes in the vitreous — the clear, gel-like substance that fills the inside of your eye. As you age, the vitreous becomes more liquid and small fibres within it clump together, casting tiny shadows on your retina. These are what you see as floaters. They are extremely common, particularly in people over 50, those who are short-sighted, or after eye surgery.
However, a sudden increase in floaters — particularly if accompanied by flashes of light or a shadow or curtain spreading across your vision — can indicate a serious condition that requires urgent attention. The most concerning possibility is a retinal detachment or retinal tear, where the vitreous pulls away from the retina and damages it. Retinal detachment is a sight-threatening emergency that requires prompt treatment (usually surgery) to prevent permanent vision loss.
If you experience a sudden shower of new floaters, new or increasing flashes of light (especially in your peripheral vision), a dark shadow or curtain spreading across your vision, or a sudden loss of vision, you should contact your optician urgently for a same-day appointment, or call NHS 111 if your optician is unavailable. Many opticians provide emergency eye care through the NHS MECS scheme and can see you the same day.
If your floaters are longstanding, have not changed, and are not accompanied by flashes or shadows, they are almost certainly harmless. Mention them at your next routine eye test so your optometrist can confirm. Most people learn to live with mild floaters, and the brain often learns to ignore them over time.