Floaters are spots or lines that seem to float in a person's field of vision. The affected person often sees these accompanied by flashes of light coming from the side of the eye.

What is going on in the body?

The clear jelly-like material that fills the eyeball is called vitreous. With normal aging, this gel may start to thicken and shrink. This may cause the gel to pull away from the internal lining of the eye. This condition is known as posterior vitreous detachment.

While some parts of the gel inside the eye thicken, other parts of the gel will liquefy. Floaters form when small clumps of protein settle out as the vitreous breaks down. When light enters the eye, it hits these small particles before reaching the retina. This is what a person perceives as spots in front of the eye.

Floaters are more common in people who are older or nearsighted. They also occur in people who have had cataract operations or laser surgery on the eye. Floaters can also follow inflammation inside the eye.

When floaters occur, a person will sometimes have quick, arc-shaped flashes of light out of the corner of the eye. These are often described as lightning flashes. Flashes may occur off and on for several weeks or even months. However, they usually disappear with time.

What are the causes and risks of the condition?

Floaters develop as a result of changes in the make up of the vitreous gel inside the eye. The gel may pull on or rub against the retina as the eye moves. The retina is the "film" on the back of the eye that helps transmit the things we see to the brain. When the gel pulls or rubs the retina, flashing lights or lightning streaks may occur in the person's vision. Flashes of light may also be a symptom of migraine headache. A person who experiences light flashes should be evaluated for migraines.