Floaters

How it works

The eye is filled with a clear jelly called the vitreous. It is mostly water held in a mesh of collagen fibres². Over time, some fibres clump together. A clump casts a shadow on the retina, and you see the shadow as a thread, dot, or cobweb¹. Floaters move with the eye and lag slightly behind it, so they dart away when you try to look at them¹. They show best against a bright, plain background such as the sky, a white wall, or a screen.

The Latin name, muscae volitantes, means “flying flies”¹. About 70% of people notice floaters at some point¹. They increase with age. In older adults the vitreous shrinks and pulls away from the retina, a change called posterior vitreous detachment, and this often releases a burst of new floaters³. Short-sighted people get floaters earlier¹.

The brain learns to ignore a stable floater over months. Most people stop noticing old ones unless they look for them¹.

Is it a problem?

Usually no. A few floaters that have been there for months or years, drifting slowly, are harmless. They do not damage vision. Surgery to remove them exists but is rarely worth the risk¹.

Get checked the same day if you notice a sudden shower of many new floaters, flashes of light at the edge of your vision, or a dark curtain or shadow across part of your view⁴. These can mean the retina is tearing or pulling away. Treated quickly, this is fixable. Left alone, it can cause permanent loss of vision⁴. Also get checked after any blow to the eye.