Those black spots drifting across your vision are almost always floaters, tiny clumps of protein inside the gel that fills your eyeball. They’re extremely common, usually harmless, and become more frequent as you age. That said, a sudden increase in black spots, especially with flashing lights or vision loss, can signal something serious that needs immediate attention.
What Floaters Actually Are
Your eye is filled with a clear, jelly-like substance called the vitreous. It’s mostly water, but it has a structure held together by microscopic collagen fibers. As you age, this gel slowly liquefies and shrinks. The collagen fibers that once held it together clump into tiny strands and specks. When light enters your eye, it hits these clumps and casts shadows on your retina, the light-sensitive tissue at the back of your eye. Those shadows are what you see as black spots, threads, or squiggly lines.
The spots move when you try to look directly at them because they’re literally floating in fluid. They tend to be most noticeable against bright, uniform backgrounds like a white wall or a blue sky.
Why Age Is the Biggest Factor
The vitreous doesn’t just form clumps over time. Eventually, it shrinks enough that it pulls away from the retina entirely, a process called posterior vitreous detachment (PVD). This is remarkably common: roughly 24% of people aged 50 to 59 have experienced it, and that number jumps to 87% by ages 80 to 89. When the vitreous separates, it often releases a new wave of floaters that can seem alarming but is typically a normal part of aging.
Before the vitreous fully detaches, the collagen fibers connecting it to the retina tug on the retinal surface. This pulling is what causes flashes of light that sometimes accompany new floaters. In most cases, those fibers break cleanly, the vitreous separates without incident, and the new floaters become a permanent but minor annoyance.
When Black Spots Signal an Emergency
A sudden shower of new floaters, especially paired with flashes of light in your peripheral vision, can mean the vitreous has torn the retina as it pulled away. Retinal tears can progress to retinal detachment, where the retina peels away from the back of the eye. As a detachment progresses, you may notice a shadow or curtain creeping across part of your visual field. If the central part of the retina (the macula) detaches, vision drops severely and rapidly.
This is a genuine emergency. The difference between a harmless new floater and a retinal tear is impossible to determine on your own. If you experience a sudden burst of new spots, flashing lights, or any loss of peripheral vision, get to an eye specialist the same day.
People with severe nearsightedness face a higher risk here. Their eyes are physically longer, which stretches the retina thinner and makes it more vulnerable to tears. The risk of retinal detachment is five to six times greater in people with high myopia compared to those with mild nearsightedness.
Other Conditions That Cause Black Spots
Bleeding Inside the Eye
Diabetic retinopathy and other vascular conditions can cause tiny blood vessels in the retina to leak blood into the vitreous. This vitreous hemorrhage looks different from standard floaters. Fresh bleeding appears as a red or dark haze, and the blood can clot quickly because the collagen in the vitreous promotes clotting. Red blood cells can remain intact in the vitreous gel for months, meaning the visual disturbance can persist until the blood is absorbed or treated.
Inflammation (Uveitis)
Inflammation inside the eye, known as uveitis, produces floaters that look and behave differently from age-related ones. Inflammatory cells accumulate in the vitreous and can form visible clumps sometimes described as “snowballs.” Unlike ordinary floaters, uveitis typically comes with additional symptoms: eye pain, redness, sensitivity to light, and blurred vision. If your black spots arrived alongside any of those, inflammation is a likely cause.
Calcium-Lipid Deposits
A less common condition called asteroid hyalosis produces tiny, glittering yellow-white particles inside the eye. These crystals contain calcium, phosphorus, and fats, with a composition similar to kidney stones. Most people with this condition don’t even know they have it until an eye doctor spots the particles during a routine exam. Despite looking dramatic under examination, asteroid hyalosis rarely affects vision.
Your Brain Will Likely Tune Them Out
If your floaters are the standard, age-related kind, there’s good news: your brain is surprisingly good at learning to ignore them. This process, called neuroadaptation, takes an average of three to six months. During that time, the spots don’t disappear, but your brain gradually stops registering them as part of your conscious visual field. Most ophthalmologists recommend waiting at least six months before considering any treatment, since the vast majority of people adapt on their own.
For the minority who remain persistently bothered after that window, the likelihood of the brain adapting on its own drops significantly.
Treatment Options for Persistent Floaters
When floaters don’t fade into the background and genuinely interfere with daily life, there are two main treatment paths. The first is a laser procedure called YAG vitreolysis, where a laser breaks up the collagen clumps into smaller pieces. In one long-term study, about 57% of patients experienced at least a 50% improvement in symptoms, with no cases of retinal tears or detachment as complications. However, people with high myopia didn’t respond as well. Only about 17% of highly nearsighted patients in that study felt significant improvement. Recurrence was rare, affecting fewer than 2% of treated patients.
The second option is a surgical procedure called vitrectomy, which removes the vitreous gel entirely and replaces it with a saline solution. This is more invasive and generally reserved for severe cases where floaters substantially impair vision.
How Floaters Get Diagnosed
A standard vision test at an optometrist’s office won’t reveal what’s happening inside your eye. Diagnosing the cause of black spots requires a dilated eye exam. Your doctor places drops in your eyes that widen your pupils, allowing light to reach the inner structures. This lets them directly examine the vitreous for floaters, check the retina for tears or detachment, look for signs of bleeding, and spot inflammatory cells. The exam itself is painless, though your vision will be blurry and light-sensitive for a few hours afterward.
Since many eye conditions that cause floaters have no pain or obvious warning signs, a dilated exam is the only reliable way to tell whether your black spots are harmless collagen clumps or something that needs treatment.