Eye Floaters Explained

You are seeing a shadow, not the thing itself

A floater is not a foreign object that has entered your eye. It is a shadow cast by a small clump of the eye's own proteins drifting inside the gel-filled chamber behind your lens. What you perceive is not the clump itself, but its shadow falling on the retina at the back of the eye.

Think of a small cloud drifting slowly across the sun on a clear day. From the ground you do not see the cloud directly. You see the shadow it casts. A floater works in exactly the same way.

Why floaters move the way they do

Your eye is filled with a clear, gel-like substance called the vitreous humour. When something is suspended within that gel, it moves as the gel moves. Every time you shift your gaze, the vitreous shifts with it, carrying whatever floats inside. When your eye stops, the vitreous keeps moving for a moment, like tea swirling in a cup after you stop stirring. This is why floaters always seem to drift just ahead of wherever you are looking. Chasing them never works, because they move with your eye.

Why they are more obvious at some times than others

Floaters almost disappear in a dim room or against a complex, patterned background, and then reappear strikingly against a bright sky or white screen. This is simply contrast. The shadow they cast is faint, and against a bright, featureless background it becomes easy to see. Nothing has changed inside your eye. Only the backdrop has changed.

What they look like

People describe floaters in remarkably consistent ways: small dots or specks, threads or strands that drift and curl, cobweb shapes that frustratingly resemble a smudge on your glasses, and occasionally a large ring or arc that appears quite suddenly. That last one has a particular cause, which we come to below.

The vitreous and what changes with age

The vitreous humour fills the large central chamber of your eye, from the lens all the way back to the retina. In a young eye it is firm, transparent, and pressed snugly against the retina. You are completely unaware of it, which is exactly how it should be.

From around the forties onwards, the vitreous gradually begins to change. The fine collagen fibres that give it structure begin to clump together, and water within the gel separates into small pockets of liquid. The vitreous is slowly transforming from a uniform jelly into something looser and more watery, with strands and clumps of collagen drifting within it. Those clumps and strands are floaters. Think of it like a snow globe that has been sitting on a shelf for decades. When it was new, the liquid was clear and the contents evenly suspended. Over time things settle and clump. The globe has not broken. It has simply aged.

Posterior vitreous detachment

For many people floaters accumulate gradually, a few new specks appearing over the years. But for a significant number of people there is a more noticeable event, called a posterior vitreous detachment, or PVD. As the vitreous becomes more liquid it eventually separates away from the retina at the back of the eye, usually over a period of hours to weeks. It is the eye's equivalent of wallpaper beginning to peel away from a wall.

When this happens, floaters appear, often suddenly and noticeably. The most characteristic floater of a PVD is a large ring or cobweb shape, sometimes called a Weiss ring, which forms where the vitreous was attached to the optic nerve. Alongside this, many people notice brief flashes of light at the edge of their vision, particularly in the dark. These happen because the vitreous, as it pulls away, tugs on the retina. The retina responds by generating a signal the brain interprets as light.

A PVD most commonly happens between the ages of 50 and 70, and it is extremely common. In the great majority of cases it is entirely benign. However, in a small number of cases the vitreous does not separate cleanly and can tug hard enough on the retina to cause a tear. A retinal tear, if left untreated, can lead to a retinal detachment, which is a genuine emergency.

Most floaters are harmless. These symptoms are not.

The vast majority of floaters do not require treatment. They are real, visible, and can be genuinely irritating, but they are not harming your eye and not a sign that anything is going wrong. There is, however, a small number of symptoms that should prompt you to seek urgent assessment the same day.

If you have had floaters for months or years, have already been examined, and nothing has changed, routine monitoring is appropriate. If floaters are new, or if anything has changed recently, an examination is sensible. In clinic, most people who come in with new floaters leave reassured after a straightforward retinal examination, which is exactly why it is worth attending rather than waiting and wondering.

How floaters are assessed

An eye specialist will examine the vitreous and retina using a technique called dilated fundoscopy. Drops are used to widen the pupil, allowing a detailed view of the inside of the eye, including the vitreous, the retina, and the area around the optic nerve. The examination is straightforward and painless, though the dilating drops temporarily make your vision blurry and sensitive to light for a few hours. The purpose of the examination is to check that the retina is intact.

What can be done

For the majority of people with stable, long-standing floaters, no treatment is needed or recommended. The brain is remarkably good at adapting, and many people find that floaters which felt very intrusive when they first appeared become far less noticeable over the following weeks and months. This process, called neuroadaptation, is real and well recognised.

For people with floaters that are genuinely affecting quality of life, there are options. Laser vitreolysis uses a laser to break up floaters. Vitrectomy, a surgical procedure to remove the vitreous, is more definitive but carries surgical risks. Both are specialist interventions, not routinely available in general practice, and are decisions to be made carefully with an ophthalmologist who has fully assessed your eye.

Practical next steps

If your floaters are new, or if anything has changed recently, the sensible next step is an eye examination. Most people find the experience reassuring. If the symptoms listed in the warning section above apply to you, please seek assessment the same day rather than waiting.

If you have already been examined and given the all-clear, the most helpful thing is to give the brain time to adapt. Floaters that feel very present now often become genuinely easier to live with over time.

Frequently asked questions

Are eye floaters normal?

Most floaters are entirely normal and related to natural changes in the vitreous gel inside the eye, especially with age. In clinic, the majority of people I see with new floaters have a completely healthy retina. They become more common from the forties onwards and in most cases are not a sign that anything is wrong with your eyesight.

When should I worry about floaters?

You should seek urgent assessment the same day if floaters appear suddenly, especially if they are accompanied by flashes of light or a shadow at the edge of your vision. The cases that concern me more are those where there is a sudden shower of new floaters rather than one or two, or where any visual disturbance accompanies them.

Can floaters go away on their own?

Many floaters become significantly less noticeable over time as the brain adapts and learns to filter them out. Most patients I see with long-standing floaters are genuinely less troubled by them after a few months, even when the floaters have not physically disappeared.

What causes floaters to suddenly increase?

A sudden increase in floaters is most often due to a posterior vitreous detachment, the natural process by which the vitreous gel separates from the retina with age. Less commonly, it can indicate a retinal problem that needs prompt assessment. This is why a sudden change always deserves an eye examination.

Do floaters mean I have a serious eye problem?

In most cases they are harmless and part of the normal ageing of the eye. However, certain patterns of symptoms can indicate a more serious issue, which is why assessment is important when floaters are new or when anything has changed. A normal examination is genuinely reassuring and worth having.