What Causes Floaters in Your Vision?

Short answer: Most floaters are caused by changes in the vitreous — the gel-like substance that fills the eye — as it liquefies and collapses with age, creating strands and clumps that cast shadows on the retina. Most are harmless. A sudden shower of new floaters, especially with flashes of light, is a medical emergency that may indicate retinal tear or detachment.

This is an important differentiation that the Eye Health and Vision Care resource emphasizes throughout its content on when to seek care. Here is everything you need to know.

The Vitreous: Where Floaters Come From

The vitreous humor is a clear, gel-like substance that fills approximately 80% of the eye’s interior, between the lens and the retina. In youth, the vitreous is uniform and clear, attached to the retinal surface.

With age — and in younger patients who are highly myopic, who have had eye surgery, or who have inflammatory eye disease — the vitreous begins to undergo a process called syneresis: it liquefies from within and the collagen fibers it contains clump together. These clumps cast shadows on the retina, which you perceive as floating specks, threads, cobwebs, or rings that move as your eye moves.

Posterior Vitreous Detachment (PVD): The Common Cause

The most common significant vitreous event in adults is posterior vitreous detachment (PVD), in which the vitreous separates from the retinal surface. This typically occurs between ages 50 and 70, though it can happen earlier in high myopes.

When PVD occurs, patients often notice:

A sudden onset of new floaters (often described as a ring or web-like shape — the Weiss ring, which is the residual attachment point)
Flashes of light (photopsia) — caused by traction on the retina as the vitreous separates

In the vast majority of cases, PVD is a benign event. The vitreous separates cleanly, the flashes resolve over days to weeks, and the floaters gradually become less noticeable as the brain adapts (though the floaters do not literally disappear — the brain learns to filter them).

When Floaters Are an Emergency

A minority of PVD cases are not benign. When the vitreous pulls away from the retina, it can tear the retinal tissue — particularly at areas of pathologically firm attachment (lattice degeneration, vitreoretinal tufts). A retinal tear, if not treated promptly, can progress to retinal detachment.

Seek emergency evaluation immediately if you experience:

A sudden shower of new floaters (dozens appearing at once, like a rain of spots or dots) — this can indicate vitreous hemorrhage from a retinal tear
Prominent flashes of light in one eye
A curtain, shadow, or darkness advancing across your visual field — this is the cardinal sign of retinal detachment
Rapid loss of central or peripheral vision

Retinal detachment is a surgical emergency. Treated promptly (within 24-48 hours), outcomes are typically excellent. Delayed treatment risks permanent central vision loss. See when should I see an eye doctor immediately for the complete list of urgent presentations.

Who Is at Higher Risk for Significant Floaters and Retinal Events?

High myopes: The elongated, thinned retina in high myopia is at significantly elevated risk for peripheral retinal tears, lattice degeneration, and retinal detachment. High myopes should have annual dilated retinal examinations and understand the symptoms that require emergency evaluation.
Post-cataract surgery patients: PVD is accelerated after cataract surgery.
Post-trauma: Direct eye trauma can cause vitreous hemorrhage or retinal tear.
Previous retinal tear or detachment: Significantly elevated risk of recurrence or fellow eye involvement.

Management of Benign Floaters

For the vast majority of people with established, stable floaters from benign vitreous changes:

No treatment is required
Most patients adapt and notice the floaters less over months
Floaters that are acutely debilitating can be treated with laser vitreolysis (YAG laser to break up floater strands) or pars plana vitrectomy (surgical removal of the vitreous) — but these procedures carry their own risks and are reserved for significantly symptomatic cases