Eye Flashes and Floaters

What are flashes and floaters?

Floaters can look like little bugs, stars, threads, or cobwebs. They move when you try to look at them and are most noticeable in bright light. They are sometimes more visible when looking at a solid, light-colored background, such as a white wall or a blue, cloudless sky.

Flashes are flickers or streaks of light that usually happen in the peripheral vision (up above, down below, or to either side of your central vision). Closing your eyes will not make them go away. You may not be able to tell in which eye the flashes happened. They are usually more visible in dark environments, such as at night.

Floaters are quite common, and may not be a problem. If you have more floaters or flashes than normal, it could be a sign of a problem with the retina (the back of the eye).

What is the cause?

Floaters usually result from changes in the vitreous. The vitreous is the gel that fills most of the eyeball. Clumps may form in the vitreous. These clumps appear as floaters across your vision.

As you get older, you may suddenly see a large floater. As a normal part of aging, the vitreous gets more watery and starts to separate from the back of the eye (the retina). After separating, the vitreous sometimes moves forward and floats in the middle of the eyeball. Then you see a large floater. This process is called vitreous detachment. It is most common after age 55.

Sometimes flashes may happen in your peripheral vision. They occur when part of the retina is tugged or torn by the separating vitreous. If a tear forms, it can lead to a retinal detachment. Retinal detachment is separation of the retina from the tissues underneath it. It can lead to a permanent loss of vision.

What are the symptoms?

  • You see spots that look like little bugs, threads, or cobwebs.
  • The spots usually shift away from your focus when you try to look at them and are most noticeable when you look at a solid, light-colored background.
  • Sometimes you also see flashing lights that happen when your eyes are either open or closed. It may be more noticeable in dim light or when you move your eyes.

How are they diagnosed?

Your eye care provider will put eyedrops in your eyes to dilate them. Then he or she will examine the inside of your eyes using special lenses and a lighted tool called an ophthalmoscope.

How are they treated?

Floaters do not require treatment. Most people learn to ignore them over time. However, flashes and floaters are sometimes a symptom of a tear in the retina. Retinal tears can be serious. Without treatment, fluid can leak through the tear and cause the retina to detach. Retinal detachment may require surgery.

The warning signs of a retinal tear or detachment include:

  • suddenly seeing many new flashes of light or many new floaters
  • loss of side vision
  • blurred or distorted vision

If you have these symptoms, call your healthcare provider right away.

How long do the effects last?

Flashes and floaters not caused by a retinal tear or detachment are harmless. They may never go away completely, but they tend to become much less noticeable with time. However, if the floaters or flashes are caused by retinal tears or detachment, you could lose your vision if you don't have them checked by your provider and get treatment as needed.

When should I call my healthcare provider?

Call your provider right away if you have a sudden onset of new flashes or floaters or if you notice that part of your vision is missing.

Reviewed for medical accuracy by faculty at the Wilmer Eye Institute at Johns Hopkins. Web site: http://www.hopkinsmedicine.org/wilmer/

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