Black spots floating in my vision: when should I worry?

The small dark spots, threads or cobwebs that drift across your vision are called floaters. The US National Eye Institute (NEI) explains that as you age, tiny strands in the vitreous, the clear gel that fills the eye, stick together and cast shadows on the retina, the light-sensitive layer at the back of the eye. NEI says almost everyone develops floaters as they get older, and the NHS says they are usually harmless, especially if you have had them a long time and they are not changing. The signs that need an eye doctor straight away are different: a lot of new floaters at once, flashes of light, or a dark shadow or curtain across part of your vision.

What are the dark spots and threads floating in my vision?

They are shadows of tiny things inside your own eye, not specks on the surface.

What floaters look like

NEI and the NHS describe floaters as small dark shapes that float across your vision. They can look like:

• spots or dots
• threads or squiggly lines
• rings
• little cobwebs

NEI notes that floaters move as your eyes move, so when you try to look at one directly, it seems to drift away.

Where they come from

Most of the inside of the eye is filled with the vitreous, a clear gel. A 2025 review by Albrecht and colleagues at Heidelberg University explains that floaters are made of microscopic collagen fibres in this gel that clump together, which happens with ageing and in nearsighted eyes. Light passing through the gel throws the shadow of these clumps onto the retina, so you see them as shapes that follow your eye movements.

Why they are easier to see against a bright background

NEI says you may notice floaters more when you look at something bright, such as white paper or a blue sky. A white wall, a bright screen or the sky on a sunny Thai afternoon makes the shadows stand out.

Who notices floaters more often?

Floaters are common at every age, and research has looked at who notices them most.

What the studies found

The NHS names a change in the gel inside the eye as one of the main causes of floaters, which is why the 2004 study, which looked at who has the gel separating from the back of the eye, is included here. In the 2013 survey by Webb and colleagues, seeing floaters did not differ clearly by age, gender, race or eye colour. In the 2026 study by Li and colleagues, 39.2% of the people who came in were nearsighted and 29.5% saw floaters in both eyes; both groups were younger on average than the others.

Nearsightedness and Thailand

NEI explains that nearsightedness usually starts between ages 6 and 14 and gets worse until the early twenties, and lists being very nearsighted as raising the chance of floaters. A 2024 review by Ian Morgan of the Australian National University found that most data from Southeast Asia show that nearsightedness at the end of schooling is still fairly modest, while two studies suggest that in young adults in Thailand and Indonesia it may be approaching the high levels seen in East Asia. The review concludes that more data are needed.

What these studies can and cannot tell you

The 2013 survey relied on people answering an app, and the clinic studies looked at people who were already seeing an eye doctor. They show that floaters are common and that nearsighted people notice them more. They cannot tell you whether your own floaters are the harmless kind; an eye examination can.

Which floaters are usually harmless, and which are urgent?

The difference lies in how they started and what comes with them.

Harmless or urgent: how to tell

Why sudden new floaters matter

A 2026 study by van Zon and colleagues at Radboud University Medical Center looked at records from 7 family doctors' practices in the Netherlands between 2012 and 2021, covering 1,181 adults who came in with new floaters or flashes. The researchers then checked how many turned out to have a serious problem with the retina.

People with many floaters, defined as 10 or more or a cloud, haze or curtain, had about 4 times the share of people with flashes only, and about 6 times when many floaters came with flashes. The study used existing records from one country, but it shows why new floaters on their own are a reason to be checked, not only flashes.

What should I do if I notice floaters?

If your floaters are long-standing and unchanged, NEI says that floaters from ageing that do not bother you probably need no treatment. If they are new, or you are unsure, have your eyes examined.

What happens at the eye exam

NEI says an eye doctor can check for floaters as part of a dilated eye exam. Drops widen your pupils so the doctor can look at the back of the eye. According to NEI, your vision may be blurry and your eyes sensitive to light for a few hours afterwards, so:

• bring sunglasses
• ask a friend or family member to drive you home

Regular eye checks

NEI suggests a dilated eye exam every 1 to 2 years for people over 60. If you are very nearsighted or have had certain eye surgery, mention it at your eye check, since NEI lists being very nearsighted and some eye surgery among the things that raise the chance of floaters.

What to tell the eye doctor

• when you first noticed the floaters, and whether they appeared suddenly
• whether you have seen flashes of light or any shadow over part of your vision
• whether you are nearsighted, and your glasses or contact lens strength
• any eye surgery or injury to the eye
• any medicines you take regularly

For other everyday eye symptoms, see Why does my eye twitch and my vision blur by evening?

When should I go to an eye doctor straight away?

NEI says to go to your eye doctor or a hospital emergency department right away if:

• you suddenly see a lot of new floaters, sometimes with flashes of light
• a dark shadow like a curtain, or a blurry area, appears at the side or in the middle of your vision

The NHS also advises getting urgent help if floaters or flashes come with blurred vision or eye pain, or start after eye surgery or an injury to the eye.

Do not wait for them to settle

Do not wait to see whether sudden new floaters, flashes or a shadow go away on their own. In Thailand, go to a hospital with an eye department, or call 1669 if you cannot get there yourself. Do not drive yourself if your vision is affected.