Eye Floaters and Flashes: When to Worry and When to Wait

Published October 1, 2026 · By Dr. Lu Eye Care · 5 min read · Eye health

Almost everyone notices floaters at some point: little specks, threads or cobwebs that drift across your vision, especially against a bright sky or a white wall. Most are harmless. But a sudden change in floaters, especially with flashes of light, can be an early warning of a retinal tear or detachment. This guide explains the difference and what to do.

What floaters are

The inside of your eye is filled with a clear gel called the vitreous. Over time, the gel slowly becomes more liquid and tiny fibers within it clump together. These clumps cast shadows on the retina, the light-sensitive layer at the back of the eye, and you see the shadows as floaters. Because they are inside the eye, they move when your eye moves and seem to dart away when you try to look at them directly.

Why floaters become more common with age

As the vitreous changes with age, it can shrink and pull away from the retina. This common event is called a posterior vitreous detachment (PVD). It often happens after age 50 and can occur earlier in people who are nearsighted, have had cataract surgery, or have had an eye injury. A PVD often causes a noticeable new floater, sometimes a ring-shaped one, and sometimes brief flashes of light.

In most cases a PVD is harmless and the symptoms fade or become less noticeable over weeks to months. In a small number of cases, however, the gel tugs hard enough on the retina to tear it.

What flashes mean

Flashes look like flickers, sparks or lightning streaks, often at the edge of your vision and more noticeable in dim light. They happen when the vitreous pulls or rubs on the retina, which responds by sending a signal your brain reads as light. Flashes are a sign of traction on the retina, which is why new flashes deserve a prompt exam.

Flashes are different from the shimmering zigzag patterns some people see during a migraine aura, which usually affect both eyes, spread over several minutes and then fade. If you are unsure which you are experiencing, get checked.

Why a retinal tear is urgent

A retinal tear allows fluid to pass under the retina, which can lift it away from the back of the eye: a retinal detachment. A detached retina stops working properly and can cause permanent vision loss if it is not repaired quickly. Tears found early can often be sealed with a laser or a freezing treatment in the office, which greatly lowers the risk of detachment. Once a detachment occurs, surgery is usually needed.

What happens at a floater exam

Your eye doctor will ask when the symptoms started and how they have changed, then dilate your pupils to examine the entire retina, including the far edges where tears often occur. Additional imaging, such as an OCT scan or ultrasound, may be used. If you have a PVD without a tear, you may be asked to return for a follow-up exam within a few weeks, because tears can develop after the initial event. You will also be told which new symptoms should bring you back sooner.

A quick vision check is not enough for new floaters; you need a dilated exam. Learn more in what to expect during a comprehensive eye exam.

Who is at higher risk of retinal tears

• People with moderate or high nearsightedness
• People who have had cataract surgery or other eye surgery
• Anyone who has had a significant eye injury
• People who have had a retinal tear or detachment in the other eye
• People with a family history of retinal detachment

People with diabetes can also develop floaters from bleeding inside the eye caused by diabetic retinopathy, which needs prompt evaluation. See diabetic eye exams for more.

Treatment for floaters

Most floaters need no treatment. The brain tends to tune them out over time, and some settle out of the line of sight. For a small number of people whose floaters are dense and seriously interfere with vision, procedures such as vitrectomy surgery or laser treatment may be discussed, but they carry risks and are not routinely recommended. Treatment of a retinal tear or detachment is a different matter: it is time-sensitive and should not be delayed.

Living with harmless floaters

• Moving your eyes up and down can shift a floater out of your central vision for a moment.
• Sunglasses and reducing glare can make floaters less noticeable outdoors.
• Keep track of your floaters. If they suddenly increase, or flashes or a shadow appear, call an eye doctor right away.
• Keep up with regular eye exams; see how often you should get an eye exam.

Common questions about floaters

Do floaters ever go away? They rarely disappear completely, but many become much less noticeable over weeks to months as they settle and the brain learns to ignore them.

Do screens cause floaters? No. Floaters come from changes inside the eye. Bright, plain backgrounds such as a white document or a blue sky simply make existing floaters easier to see.

I had a floater exam last month. Do I need another one? If your eye doctor asked you to return for a follow-up, keep that appointment. And if your symptoms change, with more floaters, new flashes or a shadow, call right away rather than waiting.

Bottom line

Old, familiar floaters that do not change are usually harmless. New floaters, especially a sudden shower of them, flashes of light or a shadow over your vision, need a dilated eye exam the same day. Acting quickly gives the best chance of protecting your vision. Not sure which professional to call? Our guide to optometrists, ophthalmologists and opticians can help.

This article is general health information and is not a substitute for an examination or personal advice from a licensed eye care professional. If you have sudden vision changes, eye pain, or new floaters or flashes, seek care promptly.