Eye floaters are caused by tiny clumps of collagen fibers inside the gel that fills your eyeball. As this gel ages and breaks down, those clumps cast shadows on the light-sensitive tissue at the back of your eye, and you see them as specks, threads, or cobweb-like shapes drifting across your vision. Most floaters are harmless, but a sudden burst of new ones can signal something serious.
The Gel Inside Your Eye Breaks Down Over Time
Your eyeball is filled with a clear, jelly-like substance called the vitreous. It’s 99% water, held in a gel-like structure by a small number of collagen fibers and a molecule called hyaluronic acid. When you’re young, this gel is firm and transparent. As you age, it gradually liquefies, a process called vitreous syneresis. The collagen fibers that once held everything together lose their even spacing and start clumping into tiny bundles.
Those clumps are your floaters. When light enters your eye and passes through the vitreous, the clumped fibers block some of it and project small shadows onto your retina. Your brain interprets those shadows as shapes drifting in your field of vision. They’re most noticeable against bright, uniform backgrounds like a blue sky or a white wall, and they seem to dart away when you try to look directly at them because the gel shifts when your eye moves.
Posterior Vitreous Detachment
The most significant age-related cause of floaters is posterior vitreous detachment, or PVD. As the vitreous liquefies and shrinks, it eventually pulls away from the retina entirely. This separation happens in stages: the gel first peels away from the central part of the retina, then gradually detaches from the edges, and finally separates from the optic nerve at the back of the eye.
PVD typically produces a noticeable increase in floaters. People often describe seeing a ring-shaped floater (called a Weiss ring), along with cobwebs, bugs, or hair-like strands. Flashes of light, especially at the edges of your vision, are also common because the shrinking gel tugs on the retina as it separates. These flashes tend to be more obvious in darker environments. The floaters from PVD often change in size and shape over four to six weeks as the separation progresses.
PVD itself isn’t painful and doesn’t cause permanent vision loss. But it can sometimes tear the retina as the gel pulls away, which is why any sudden shower of new floaters deserves prompt attention.
Diabetes and Blood Vessel Damage
Floaters don’t always come from collagen clumps. In people with diabetes, chronically high blood sugar damages the tiny blood vessels in the retina. The walls of these vessels weaken over time, and they can eventually rupture and leak blood into the vitreous. Even a small amount of blood in the gel creates floaters, often appearing as dark spots, streaks, or a reddish tint to your vision. As diabetic eye disease progresses, symptoms can include blurred vision, distorted shapes, and partial vision loss in addition to floaters.
Inflammation Inside the Eye
Uveitis, an inflammation of the inner layers of the eye, is another cause. When the immune system sends white blood cells into the eye to fight infection or as part of an autoimmune response, those cells and the debris they produce float in the vitreous and cast shadows just like collagen clumps do. Floaters from inflammation tend to appear more suddenly than age-related ones and may come with eye redness, pain, or light sensitivity.
Calcium Crystal Deposits
A less common condition called asteroid hyalosis causes tiny mineral deposits to form inside the vitreous. These particles contain calcium, phosphorus, and fatty compounds, with a crystal structure similar to gallstones or kidney stones. Under direct light, they glitter like stars. Despite their dramatic appearance during an eye exam, most people with asteroid hyalosis don’t notice significant vision problems. The condition is usually found incidentally and rarely requires treatment.
Warning Signs That Need Immediate Attention
A few floaters that drift around slowly are normal. What’s not normal is a sudden change. You should get to an eye specialist or emergency room right away if you notice:
- Many more floaters than usual, appearing all at once
- Flashes of light in the same eye as the floaters
- A gray curtain, shadow, or blurry area blocking part of your vision
- Darkness creeping in from the sides of your vision
These symptoms can indicate a retinal tear or retinal detachment. The retina doesn’t have pain receptors, so these events are painless, which makes it easy to dismiss them. But if a detachment isn’t treated quickly, it can lead to permanent vision loss. The earlier it’s caught, the better the outcome. A dilated eye exam can detect small tears before they progress.
Treatment Options for Persistent Floaters
Most floaters fade on their own or at least become less noticeable as your brain learns to ignore them. For floaters that remain bothersome, two main treatments exist.
Laser treatment (called vitreolysis) uses focused laser energy to break apart the collagen clumps. In one study of patients with Weiss ring floaters, 53% experienced significant or complete elimination of symptoms after laser treatment, while none in the untreated comparison group improved. The procedure is done in an office setting, and most patients need only a single session. Temporary tiny bubbles may appear in your vision afterward but resolve on their own. Serious complications are rare.
Surgery to remove the vitreous gel entirely (vitrectomy) is the more definitive option, but it carries real risks. A systematic review of outcomes found that roughly 1 in 3 patients developed cataracts after the procedure. Retinal tears occurred in about 3% of cases, and retinal detachment in about 1.5%. Patient satisfaction after surgery tends to be high, but those complication rates mean it’s typically reserved for floaters that significantly interfere with daily life, like difficulty reading or driving.
For most people, floaters are a nuisance rather than a medical problem. The key distinction is between the gradual appearance of a few drifting specks, which is a normal part of aging, and a sudden explosion of new floaters or visual changes, which warrants same-day evaluation.