What Causes Black Floaters In Your Eyes? Why It Happens

Black floaters are tiny clumps of gel or cells drifting inside the vitreous — the clear jelly that fills the back of your eye. They cast shadows on your retina, and those shadows are what you see. The most common cause is age-related changes in the vitreous, though they can also appear after eye injury, inflammation, or a retinal tear.

Most people notice them as specks, squiggles, or cobweb shapes that drift when they try to look at them directly. They are usually harmless. Sometimes, though, floaters are the first sign of a retinal tear or detachment — a medical emergency that needs immediate attention.

What Causes Black Floaters In Your Eyes?

The vitreous is about 99% water, with the rest made up of collagen fibers and hyaluronic acid. It has a gel-like consistency for most of your life. Over time, the collagen fibers can clump together. When light enters the eye, these clumps cast shadows on the retina. Your brain interprets those shadows as floaters.

This process — called vitreous syneresis — is the single most common reason people see floaters. It is a normal part of aging. By age 70, a majority of people have some degree of vitreous liquefaction and collagen clumping, though not everyone notices it.

Other causes include:

• Posterior vitreous detachment (PVD) — the vitreous pulls away from the retina. This is very common after age 50 and usually harmless, but it can sometimes tear the retina.
• Eye injury or surgery — trauma or procedures like cataract surgery can introduce blood cells or debris into the vitreous.
• Inflammation (uveitis) — inflammatory cells can enter the vitreous and appear as floaters.
• Bleeding into the vitreous (vitreous hemorrhage) — often from diabetic retinopathy or retinal tear.
• Retinal tear or detachment — this is the urgent one. A sudden shower of new floaters, especially with flashes of light or a curtain over your vision, needs immediate evaluation.

Less commonly, floaters can result from intraocular tumors or lymphoma, but these are rare.

Why Do Floaters Move When I Try To Look At Them?

Floaters drift because they are suspended in fluid. When your eye moves, the fluid moves, and the floater moves with it. When your eye stops, the floater keeps going for a moment — that’s why it seems to dart away when you try to look directly at it.

The reason you can’t ever “catch” a floater is anatomical. The floater is inside the vitreous, floating in front of your retina. Your eye movements shift the fluid, which shifts the floater. It’s a mechanical mismatch between where you look and where the floater sits.

This movement pattern is actually one clue that helps distinguish harmless floaters from something more serious. Harmless floaters tend to drift and settle. A retinal detachment may cause a fixed shadow or curtain that does not move with eye movement.

When Are Floaters A Sign Of Something Serious?

A sudden increase in floaters — especially if accompanied by flashes of light or a dark curtain across part of your vision — is a red flag for retinal tear or detachment. This is a medical emergency. Delays in treatment can lead to permanent vision loss.

Signs that warrant immediate attention:

• A sudden shower of new floaters, often described as “cobwebs” or “soot”
• Flashes of light, especially in your peripheral vision
• A shadow or curtain that appears to cover part of your vision
• Floaters after eye trauma
• Floaters with eye pain, redness, or blurred vision

Posterior vitreous detachment is the most common cause of sudden new floaters. Most PVDs do not cause a retinal tear. But when a tear does happen, it can progress to detachment within days. That’s why any sudden change in floaters needs a dilated eye exam promptly — not next month.

One non-obvious point: the number of floaters you see is not a reliable indicator of severity. A single large floater can be harmless. A small new floater with a flash of light can signal a tear. Context matters more than count.

Who Is Most Likely To Get Floaters?

Floaters become more common with age, particularly after 50. But age is not the only factor. Nearsightedness (myopia) increases risk because a longer eyeball stretches the vitreous and makes collagen clumping more likely earlier in life.

Other risk factors include:

• Diabetes, especially with diabetic retinopathy
• Previous eye surgery, such as cataract surgery
• Eye inflammation or infection
• Trauma to the eye
• Family history of retinal detachment

Floaters can also occur in younger people, particularly those with high myopia. They are not exclusively an older person’s problem.

Can Floaters Be Treated Or Removed?

Most floaters do not need treatment. They often become less noticeable over time as the brain learns to ignore them — a process called neuroadaptation. The floaters are still there, but your brain filters them out.

For the minority of people whose floaters are dense, persistent, and interfere with daily vision, two options exist:

• Laser vitreolysis — a laser breaks up the floater clumps. Evidence for its effectiveness is mixed. Some patients report improvement; others do not. It is not universally recommended, and not all ophthalmologists offer it.
• Vitrectomy — surgical removal of the vitreous gel. This is effective but carries real risks, including infection, bleeding, cataract formation, and retinal detachment. It is generally reserved for severe cases.

No eye drops, supplements, or home remedies have been shown in clinical trials to remove or dissolve floaters. Products marketed for floater relief have no established evidence behind them.

How Are Floaters Diagnosed?

An eye doctor diagnoses floaters by dilating your pupils and examining the inside of your eye with a slit lamp and an ophthalmoscope. This allows direct visualization of the vitreous and retina. If a retinal tear is suspected, additional imaging may be used.

Optical coherence tomography (OCT) can help assess the retina and vitreous relationship. B-scan ultrasound may be used if the view is blocked by blood or dense floaters.

There is no blood test or scan that “detects” floaters independently. The diagnosis is clinical — based on your symptoms and what the doctor sees inside your eye.

Do Floaters Ever Go Away On Their Own?

Many floaters become less bothersome over months to years. The clumps may settle lower in the vitreous, out of the central visual axis. The brain also adapts. But the underlying collagen clumps do not truly dissolve or disappear in most cases.

Some floaters persist indefinitely. If they remain visually significant and interfere with reading, driving, or daily function, discuss options with an ophthalmologist. The decision to treat is individualized — there is no universal threshold.

What Should You Do If You Notice New Floaters?

See an eye doctor promptly. Same-day or next-day evaluation is appropriate if the floaters came on suddenly or are accompanied by flashes or a curtain. If floaters are longstanding and unchanged, a routine exam is reasonable.

Do not wait to see if new floaters go away on their own. A retinal tear can progress to detachment within days. Treatment for a tear is much simpler and more successful than treatment for a detachment.

If you have risk factors — high myopia, diabetes, prior eye surgery, or a family history of retinal detachment — be especially attentive to any change in your floaters. Know your baseline. A change from that baseline is the signal to act.