Eye Floaters & Light Flashes: What are they?

Written By: Susannah Lockett

Eye floaters are bits of a protein called collagen suspended in the fluid inside the eyeball called the vitreous humor. As these bits of protein float toward the back of the eye, they cast shadows on the retina.

It’s these shadows you see and what you perceive as eye floaters. These are usually squiggly lines or dots that are far more noticeable against a bright white background. Most people adjust to floaters and may not even notice them much over time.  Some people think that floaters may be caused by astigmatism, which is basically a condition that occurs when your eye is not completely round,  but generally, this is not the case.

Eye Floater Dangers

Although they can be annoying, floaters are usually benign and not a cause for concern. Unless they appear suddenly and are accompanied by flashes of light, eye floaters are typically not a sign of a serious condition.

However, in rare cases, floaters may indicate a retinal detachment, eye infection, eye injury, uveitis, and bleeding inside the eye.

What do Eye Floaters Mean?

Usually, they don’t mean much of anything. Floaters often just seem to appear as part of the aging process or for no apparent reason at all in some people. Although they can be signs of a serious problem, they usually aren’t.

Although some people think that eye floaters are associated with high blood pressure, they’re not. High blood pressure may affect the optic nerve with possibly serious consequences, but it does not cause floaters.

Neither does multiple sclerosis or MS, an autoimmune neurological condition often affecting the eyes with pain and difficulty focusing. MS can sometimes cause uveitis, an inflammation of the more inner part of the eye, but it doesn’t cause floaters.

Cataract surgery can cause an appearance of or increase in eye floaters, although floaters are not a sign of cataracts or otherwise associated with them. Cataract surgery will not remove existing floaters.

Will Eye Floaters Go Away?

Generally speaking, no. Floaters are typically permanent. As part of the normal aging process, the vitreous humor both shrinks and becomes more liquid. This process is called vitreous degeneration.

As the vitreous humor becomes less dense and more liquid, floaters can move about more easily and are more likely to cast shadows on the retina. This can cause a perceived increase in floaters, whether this is actually true or not.

This is why it’s so important to report sudden floaters or bunches of newly developed floaters to your eye care professional right away. It is the only way to be sure there is nothing serious going on with your eyes.

Removal of Eye Floaters

Only a procedure called laser vitreolysis or another procedure called a vitrectomy can remove floaters. As its name suggests, laser vitreolysis uses a laser to eliminate floaters. It’s less invasive than a surgical vitrectomy and carries fewer risks.

For this reason, laser vitreolysis is the most common procedure performed to remove very large floaters for those people who feel they compromise their vision.


What About Flashes of Light?

This is a classic symptom of a possible retinal detachment, a medical and surgical emergency. Retinal detachment can be successfully treated and sight preserved when it’s treated immediately.

However, flashes of light appearing at the far corners of the peripheral visual field are often benign and are caused again by changes in the vitreous humor. As the jelly-like vitreous humor substance rubs or tugs against the retina, a sensation of a flashing light may be created.

This often occurs as part of the normal aging process and is generally harmless. However, only your eye care professional can tell you for sure what the cause of a flashing light is.


Migraine is another possible cause of visual flashing lights. This isn’t caused by the eye itself but rather by changes in the head’s blood vessels. Migraine causes these vessels to suddenly dilate, usually only on one side of the head.

Throbbing, intense pain in one temple area is a classic sign of a migraine.
Dilation of these vessels can cause severe pain, nausea, sensitivity to light, and in some types of migraine called ocular migraines, flashing lights. Attacks of ocular migraine tend to be limited to periods of 30 minutes or less.

A form of migraine called migraine with aura can also cause visual symptoms like flashing lights or strange, squiggly black lines that seem to jump around at the periphery of the visual field. Migraines are more common in women than in men.

Differences between Eye Floaters and Flashes

Floaters have a physical cause: the tiny bits of protein or collagen suspended in the vitreous humor. Flashes can have different causes, but when they occur as part of the aging process, they’re typically caused by a pulling of the vitreous humor. The light-sensitive retina then causes this to be perceived as flashing lights.

Should you See an Eye Doctor?

Absolutely. You should get a comprehensive eye exam at least yearly or as recommended by your eye care professional. Some people may have certain eye conditions that need to be treated or monitored more often than once a year.

Flashing lights in the far periphery of the visual field caused by a degeneration of the vitreous related to normal aging typically seem more intense as you look to the far left or right. They may not be prominent or even visible at all except in darkness.

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Our physicians will diagnose your eye problem and create a treatment plan just for you, from eye exams to glasses and contacts, dry eye, blepharitis, and much more.

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Published on: Sep 21, 2021
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