Those squiggly lines drifting across your vision are called floaters, and they’re one of the most common visual phenomena people experience. They’re caused by tiny clumps of collagen fibers floating inside the gel-like fluid that fills your eye. When light enters your eye, these clumps cast shadows on the retina at the back of your eye, and your brain registers those shadows as lines, dots, cobwebs, or little translucent worms. Roughly three out of four adults have them.
Why They Move When You Look at Them
Your eye is filled with a clear, jelly-like substance called the vitreous. It’s mostly water, but it contains a network of collagen fibers that give it structure. Over time, some of those fibers break free and drift around inside the gel. Because they’re suspended in fluid, they shift every time your eye moves, which is why floaters seem to dart away when you try to look directly at them. They’re not on the surface of your eye. They’re inside it, casting tiny shadows the same way a speck on a projector lens throws a shadow onto a movie screen.
Most people describe them as grey or semi-transparent shapes: squiggly lines, threads, small dots, rings, or cobweb-like patterns. They’re usually most noticeable against bright, uniform backgrounds like a blue sky, a white wall, or a computer screen. In dim lighting, you may not notice them at all.
What Causes Them
The single biggest cause is aging. As you get older, the vitreous gel gradually shrinks and becomes more liquid. This process pulls collagen fibers loose and causes them to clump together. Most people start noticing floaters in their 40s or 50s, though younger people get them too.
Nearsightedness (myopia) is another significant risk factor. People who are nearsighted tend to develop floaters earlier because their eyes are longer than average, which puts more mechanical stress on the vitreous. A family history of retinal tears or detachment also raises your risk.
A major milestone in the floater timeline is something called posterior vitreous detachment, or PVD. This happens when the vitreous gel shrinks enough that it separates from the retina entirely. It’s a normal part of aging and often triggers a sudden crop of new floaters, sometimes along with brief flashes of light. PVD itself isn’t dangerous, but the pulling action on the retina during detachment can occasionally cause a tear.
Less Common Causes
Not all floaters come from normal aging. Inflammation inside the eye, a condition called uveitis, can produce floaters along with eye pain, redness, blurry vision, and light sensitivity. The inflammation affects the gel and the structures around it, releasing debris that floats through your field of vision. Bleeding inside the eye from diabetes, an injury, or a torn blood vessel can also create floaters that look darker or more numerous than the typical age-related kind.
When Floaters Signal Something Serious
A few floaters that have been around for months or years are almost always harmless. The situation changes when the pattern shifts suddenly. The warning signs of a possible retinal tear or retinal detachment include a sudden burst of new floaters (far more than you’re used to), flashes of light in one or both eyes, and a dark shadow or curtain-like effect creeping across part of your vision. Any of these warrants an urgent eye exam, ideally within hours.
Retinal detachment is painless, which makes the visual warning signs easy to dismiss. But if the retina separates from the tissue behind it, it loses its blood supply and can cause permanent vision loss without prompt treatment. According to American Academy of Ophthalmology guidelines, even patients who have a PVD with no retinal break still carry about a 2% chance of developing a retinal tear in the following weeks, so follow-up exams matter.
How Your Brain Adapts Over Time
For the majority of people, floaters don’t require any treatment because the brain gradually learns to tune them out. This process, called neural adaptation, works the same way you stop noticing background noise after living near a busy road for a while. Your visual system essentially filters the shadows out of conscious awareness. The floaters are still physically there, but you stop registering them most of the time.
The timeline varies. Some people stop noticing new floaters within a few weeks. For others, the adjustment takes three to six months. Floaters can also settle lower in the eye over time, drifting out of your central line of sight, which helps.
Treatment Options for Persistent Floaters
If floaters are genuinely interfering with your daily life (difficulty reading, trouble driving, constant visual distraction that doesn’t improve with time), two treatment options exist.
The first is laser vitreolysis, a procedure where a focused laser beam breaks up or vaporizes the collagen clumps inside the eye. It’s done in an office setting, and studies show it can significantly reduce or eliminate visible floaters. In one study, all treated eyes showed a measurable reduction in vitreous opacity on imaging. About half of patients in a separate controlled trial reported complete or near-complete symptom relief after laser treatment. Side effects are generally mild: some patients notice small temporary black dots from gas bubbles created during the procedure, but these absorb on their own. No significant changes in vision, eye pressure, or retinal health were observed in follow-up.
The second option is vitrectomy, a surgical procedure that removes the vitreous gel entirely and replaces it with a saline solution. This is more invasive but also more definitive. A large meta-analysis found that at least 90% of patients were satisfied or had symptom relief after the surgery, with some individual studies reporting resolution rates above 95%. The trade-off is a meaningful risk of complications. Cataract development is the most common, occurring in roughly one out of every three patients (this applies mainly to people who haven’t already had cataract surgery). Retinal tears happen in about 3% of cases, and retinal detachment in about 1.5%. Because of these risks, vitrectomy is typically reserved for floaters that have persisted for at least three months and significantly affect quality of life.
Living With Floaters Day to Day
Most floaters are a nuisance, not a medical problem. A few practical habits can reduce their impact while your brain adapts. Wearing sunglasses on bright days cuts down on the contrast that makes floaters most visible. Adjusting screen brightness or using a slightly tinted background on your computer can help too. When a floater drifts into your central vision, shifting your gaze quickly up and down can move the vitreous fluid enough to push it aside temporarily.
The key thing to remember is the difference between stable floaters and changing ones. A handful of squiggly lines you’ve had for years is normal. A sudden shower of new floaters, flashes of light, or any shadow across your visual field is not, and needs same-day evaluation by an eye care provider.