Floaters and Flashes

When people reach middle age, the vitreous gel may start to thicken or shrink, forming clumps or strands inside the eye. The vitreous gel pulls away from the back wall of the eye, causing a posterior vitreous detachment. This is a common cause of floaters. As we grow older, it is also more common to experience flashes.

The appearance of floaters and flashes may be alarming, especially if they develop very suddenly. An eye doctor should be called right away if the following symptoms are noticed as they can be signs of a retinal tear or detachment (especially if you are over 45 years of age):

  • A sudden increase in size and number of floaters
  • A sudden appearance of flashes
  • Having a shadow appear in the periphery (side) field of vision
  • Seeing a gray curtain moving across the field of vision
  • Having a sudden decrease in vision

Floaters

Healthy Retina
Floaters in the Vitreous

Sometimes small specks or clouds moving can be seen in the field of vision. These are called floaters. They can often be seen when looking at a plain background, like a blank wall or blue sky. Floaters are actually tiny clumps of gel or cells inside the vitreous, the clear, gel-like fluid that fills the inside of the eye.

While these objects look like they are in front of the eye, they are actually floating inside it. What is seen are the shadows these clumps of gel cast on the retina, the layer of cells lining the back of the eye that senses light and allows clear vision. Floaters can appear as different shapes, such as little dots, circles, lines, clouds, or cobwebs.

Flashes

When the vitreous gel rubs or pulls on the retina, flashing lights or lightning streaks can be seen. This is a similar sensation as when someone gets hit in the eye and sees "stars". The flashes of light can appear off and on for several weeks or months.

As people get older, it is more common to experience floaters and flashes as the vitreous gel changes with age, gradually pulling away from the inside surface of the eye.

Patients at risk for floaters and flashes

As a result of aging, it is more common to experience floaters and flashes. Floaters and flashes are also caused by posterior vitreous detachment, where the vitreous gel pulls away from the back of the eye. This condition is more common in people who:

  • Are nearsighted
  • Have undergone cataract operations
  • Have had YAG laser surgery of the eye
  • Have had inflammation (swelling) inside the eye

Are floaters and flashes serious?

If a sudden increase in floaters and flashes of light are experienced, these symptoms can indicate a torn or detached retina which needs to be evaluated immediately by an ophthalmologist. If the vitreous gel shrinks and pulls away from the wall of the eye, the retina can tear. This sometimes causes a small amount of bleeding in the eye that may appear as new floaters. A torn retina is always a serious problem, since it can lead to retinal detachment.

Some people experience flashes of light that appear as jagged lines or "heat waves" in both eyes, often lasting 10 to 20 minutes. These are not flashes from the vitreous gel rubbing or pulling on the retina; instead, these types of flashes are usually caused by a spasm of blood vessels in the brain, called a migraine.

If a headache follows the flashes, it is called a migraine headache. However, jagged lines or heat waves can occur without a headache. In this case, the light flashes are called ophthalmic migraine. An ophthalmologist should be contacted if these symptoms are experienced.

Diagnosing floaters and flashes

When an ophthalmologist examines the eye, the pupils may be dilated (enlarged) with eyedrops. This allows the doctor to observe areas inside the eye, including the retina and vitreous. If the eyes have been dilated, the eyes will be sensitive to light and up close vision may be fuzzy. It is recommended patients who are dilated have a driver at his or her exam.

Treating floaters and flashes

Floaters may be a symptom of a tear in the retina, which is a serious problem. If a retinal tear is not treated, the retina may detach from the back of the eye. The only treatment for a detached retina is surgery.

Other floaters are harmless and fade over time or become less bothersome, requiring no treatment. Surgery to remove floaters is almost never required. Vitamin therapy will not cause floaters to disappear.

Typically floaters that have formed gradually are not a concern and can be monitored with regular eye exams. However, if a sudden increase in the size or amount of floaters or a sudden appearance of light flashes — accompanied by any change in vision, it is necessary to see an ophthalmologist immediately.