Floaters: Why Do They Occur?

Sooner or later, most of us will develop floaters. As their name implies, these wispy, string-like fibers “float” across your field of vision. Although they are usually harmless, in some cases, floaters can be a sign of a serious vision condition.

How Do I Know if I Have Floaters?

Floaters have several common characteristics:

  • They slowly drift across your visual field at random.
  • They look like strings, cobwebs or dark specks.
  • They move out of your field of vision if you try to look directly at them.
  • You are more likely to see them when you stare at solid background, such as a wall.

What Causes Floaters?

Your eye is filled with a gel-like substance called the vitreous that gives the eye its shape. As you age, the vitreous begins to shrink slightly, which can cause the gel to clump together and form floaters. Light cannot pass through these clumps. If you have floaters, what you actually see is the shadow the clumps create on your retina.

Who Gets Floaters?

Since floaters are typically age-related, you will probably begin to experience them after age 40. You may be more likely to develop floaters if you are nearsighted or have diabetic retinopathy, a condition that affects the blood vessels in the retina and can lead to vision loss. Floaters can also form if you injure your eye or have had cataract surgery complications.

Two Conditions That Can Increase Floaters

A sudden increase in floaters is often caused by one of these conditions:

  • Vitreous Detachment. The fibers of the vitreous are attached to the retina, the layer of light-sensing cells that lines the back of the eye. In some cases, an entire section of the vitreous detaches from the retina, causing a sudden increase in the number of floaters you see. A vitreous detachment can also be accompanied by flashing lights in your peripheral vision. Although this condition does not permanently affect your vision, it can be annoying when the number of floaters you see suddenly increases.
  • Retinal Detachment. Sometimes the vitreous detaches from the retina with enough force that it causes a retinal detachment. Retinal detachments occur when all or part of the retina peels away from the back of the eye. Although most floaters are not caused by a retinal detachment, you should be aware of the possibility if you notice a sudden increase of floaters accompanied by blurred vision, a curtain over your field of vision, flashes of light or decreased peripheral vision. If retinal detachments are not treated promptly, they can lead to permanent vision loss.

When Should I See My Optometrist?

Make an appointment with your eye doctor if floaters interfere with your vision or if you are not sure if you’re experiencing floaters or another eye issue. It’s not always easy to tell the difference between a vitreous detachment and a retinal detachment, since both cause light flashes and an increase in floaters. Call your eye doctor as soon as possible if you experience these symptoms. He or she will provide a comprehensive examination that will help him determine the cause of your problem.

Are you concerned about your floaters, or is it time for your next eye examination? Call us and schedule an appointment for a comprehensive vision exam.

You may experience slightly different symptoms depending on the way your floaters develop. This list describes the most common shapes.

What Do Those Floater Shapes Mean?

  • Strings, Circles, Cobwebs, Dark Specks and Squiggly Lines. You will probably see one of these floater types when your vitreous fibers clump together due to aging.
  • Black Dots.Sometimes when the vitreous shrinks, it tugs on blood vessels in your retina, causing them to leak blood. When this occurs, you may see many black dots in your field of vision. The blood is usually reabsorbed during the next several months, and the dots usually go away on their own.
  • Cobwebs or Mist.Floaters that occur after a vitreous detachment often look like cobwebs. Although cobwebs are a common floater type, you may see more of them after a detachment. It may also appear as if you are viewing the world through a mist.

Keep in mind that a sudden increase in floaters, a decrease in vision, and flashing lights can be signs of a retinal detachment. Call your optometrist immediately if you notice any signs that concern you.


National Eye Institute: Facts About Floaters, 10/09


Everyday Health: The Facts About Floaters and Flashes


Mayo Clinic: Eye Floaters, 1/17/15


All About Vision: Eye Floaters, Flashes and Spots, 1/16