Floaters are the small dots, threads, rings and cobweb shapes that drift across your vision, most obvious against a bright background such as a clear sky or a white wall. They are caused by tiny clumps forming in the vitreous gel that fills the eye, and are usually a normal, harmless part of ageing. However, a sudden increase in floaters — particularly with flashing lights or a dark shadow — can signal a retinal tear or detachment and needs a same-day eye examination.
What are floaters?
The inside of the eye is filled with a clear jelly called the vitreous. With age this gel becomes more watery and its fine fibres clump together, casting shadows on the retina that you see as floaters. Most people develop some floaters over time and learn to ignore them.
A common trigger is posterior vitreous detachment (PVD), where the vitreous gel peels away from the retina — a normal age-related event that often causes a sudden batch of new floaters and brief flashes. Usually this is harmless, but because the same symptoms can accompany a retinal detachment or a vitreous haemorrhage, new symptoms should always be checked.
Symptoms of floaters
Floaters look different from person to person, but commonly appear as:
- Small black or grey dots drifting across your vision
- Threads, squiggly lines or cobwebs that move when you move your eye
- Ring-shaped shadows (often after a vitreous detachment)
- Shapes most visible against bright, plain backgrounds
Seek a same-day assessment if you notice a sudden shower of new floaters, flashing lights, a dark curtain or shadow spreading across your vision, or any sudden loss of sight — these can be signs of a retinal tear or detachment. Our guide on when to worry about floaters explains the warning signs.
New floaters or flashing lights? A dilated retinal examination checks for a tear so it can be treated before the retina detaches.
Book a retinal assessmentCauses & risk factors
Most floaters are due to normal ageing of the vitreous, but some factors make them more likely or more significant:
- Age over 50 — vitreous changes and posterior vitreous detachment become common
- Short-sightedness (myopia) — floaters and retinal tears occur earlier and more often
- Previous cataract surgery or eye surgery
- Eye injury or inflammation inside the eye (uveitis)
- Diabetes — bleeding from diabetic retinopathy can cause sudden floaters
How floaters are diagnosed
The key purpose of the examination is to confirm the floaters are harmless and, crucially, to rule out a retinal tear:
- Dilated fundus examination — drops widen the pupil so the consultant can examine the whole retina for tears or detachment. This is the essential test.
- Slit-lamp examination — assesses the vitreous and front of the eye.
- OCT imaging — a detailed scan of the retina and macula where needed.
- B-scan ultrasound — used if bleeding or dense floaters prevent a clear view of the retina.
- Visual acuity testing — checks that central vision is unaffected.
Treatment options
The great majority of floaters need no treatment beyond reassurance once a tear has been excluded — see our floaters treatment overview for full detail.
- Reassurance and monitoring — most floaters become less noticeable over weeks to months as the brain learns to ignore them.
- Urgent laser for a retinal tear — if the examination finds a tear, it is sealed promptly with laser to prevent a detachment.
- YAG vitreolysis — a laser treatment that can break up selected large, persistent floaters; see YAG vitreolysis.
- Vitrectomy — for the small number of people with severe, debilitating floaters, a vitrectomy removes the vitreous gel and the floaters with it.