Floaters: when to worry and when not to

Almost everyone develops floaters eventually. They are shadows cast on the retina by strands in the vitreous gel that fills the eye, and in the great majority of cases they are a nuisance rather than a warning.

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Go to eye casualty or A&E today, not to a private clinic, if you have a sudden shower of new floaters, new flashing lights, or a dark curtain or shadow moving across your vision. These can mean the retina is tearing or detaching.

A detachment treated within a day or two usually does well. The same detachment left for two weeks often does not. Nothing else on this website is as time-critical as this.

The ordinary kind

Floaters that have been drifting about for years, have not changed, and come without flashes are the common kind. They tend to be more noticeable against a bright, plain background — a white wall, a clear sky, a screen — and less so as the day goes on. Most people stop noticing them over time.

The middle ground

Between the two sits posterior vitreous detachment, where the gel separates from the retina. It is very common after fifty, produces a sudden increase in floaters and often some flashes, and is usually harmless — but it carries a small risk of tearing the retina on its way, which is why it needs examining promptly rather than being assumed to be fine.

What an examination involves

Dilating drops, then a careful look at the whole retina including the far edges where tears usually occur. About half an hour, no discomfort, and you should not drive afterwards.