Are Eye Flashes and Floaters Harmless?

Reviewed on 10/6/2022
Woman experiencing eye floaters covering eyes with hands
Eye flashes and floaters are common and while usually harmless, but can require immediate medical attention if you have other symptoms such as new, sudden onset of floaters and vision changes.

Eye flashes and floaters are common and while usually harmless, in some cases they can be signs of problems in the eye. 

An eye flash is a spark or spot of light that flickers across the field of vision that happens when the vitreous humor, the gel that fills the eyeball, bumps, rubs, or tugs against the retina, the layer of cells lining the back wall inside the eye that sense light and sends signals to the brain which translate into what you see. Eye flashes may sometimes be described as “shooting stars” or “streaks of lightning.”

An eye floater is used to describe a flake of protein or a tiny cluster of cells stuck in the vitreous humor. The spots of protein or cell clusters appear as specks, threads, or even cobweb-like images in the line of vision that move as your eyes move. If you try to look directly at them, they seem to move away from the center of your vision. What you are actually seeing is not the specks themselves but the shadows they cast onto the retina. 

Both eye flashes and floaters are usually harmless, but they may be a warning sign of conditions that can lead to vision loss.

See a doctor right away if you experience eye flashes or floaters and:

  • New or sudden onset of floaters and flashes of light in the eye
  • A dark area, gradual shading, or a “curtain’” across your vision
  • A lot of new floaters that appear suddenly, sometimes with flashes of light 
  • A blurred area in the side or central vision
  • A rapid decline in sharp, central vision
  • A sudden increase in flashes of light or repeated flashes of light
  • Flashes of light occur along with cloudiness or dark spots in vision
  • Flashes of light occur after being hit in the eye or face
  • Cloudy floaters (gray or dark spots that move back and forth in your vision)
  • Vision changes

These could be signs of a torn or detached retina, which could lead to blindness if not promptly and properly treated. 

What Are Symptoms of Eye Flashes and Floaters?

Symptoms of eye flashes may include: 

  • Looks like streaks of lightning
  • Looks like stars
  • May occur on and off over time

Symptoms of eye floaters may include: 

  • Specks, threads, or cobweb-like images in the line of vision 
  • When you try to look at a floater directly, it appears to move away
  • May be more apparent when looking at something bright, such as white paper or a blue sky

What Causes Eye Flashes and Floaters?

The vitreous gel inside the eyeball slowly shrinks with age and these normal changes can often cause eye flashes and floaters. As the vitreous shrinks or changes, it can pull on the retina, which can result in flashes of light. The vitreous shrinkage also causes it to becomes stringy, and these strands cast shadows on the retina, which are seen as floaters. 

Eye flashes may also happen if you are hit in the eye or rub the eyes too hard. 

20 Eye Floaters and Flashes Causes and Risk Factors

More serious conditions that can cause eye flashes include:

  • Choroidal neovascular membranes
  • Cytomegalovirus retinitis
  • Detached and torn retina
  • Histoplasmosis
  • Migraine
  • Posterior vitreous detachment
  • Stickler syndrome
  • Vitreomacular traction
  • Hereditary retinal diseases like retinitis pigmentosa or choroideremia

More serious conditions that can cause eye floaters include:

  • Eye infections
  • Eye injuries
  • Eye inflammation
  • Bleeding in the eye
  • Vitreous detachment 
  • Torn retina
  • Detached retina

Nearly everyone develops floaters as they age, but those at higher risk include people who: 

How Are Eye Flashes and Floaters Diagnosed?

The cause of eye flashes and floaters is diagnosed by an eye doctor (ophthalmologist) as part of a dilated eye exam. Eye drops are administered to dilate (widen) the pupil and the eyes are examined for floaters and other eye problems.

If the dilated eye exam does not reveal the cause of the symptoms, additional testing, such as an ultrasound of the eye, may be needed.

What Is the Treatment for Eye Flashes and Floaters?

Occasional flashes of light caused by vitreous changes from aging do not need treatment and most people will eventually get used to them. 

If eye flashes are caused by another eye condition, that condition may need to be treated.

Treatment for floaters depends on the cause. 

  • If floaters are caused by normal aging and they are not bothersome, then treatment is not usually needed
    • Laser treatment may sometimes be suggested for benign (harmless) floaters, but this approach hasn’t been carefully studied and the risk to vision from the surgery is usually greater than the problem posed by the floater
    • Often simply moving eyes around is enough to shift the floater for temporary relief
  • If floaters are caused by another eye condition, that condition may need to be treated
  • If floaters make it hard to see clearly and interfere with daily life, a surgery called a vitrectomy may be performed to remove the floaters

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Reviewed on 10/6/2022

Image source: iStock Images