What Are Those Strange Eye “Floaters” You See In Your Vision?

The strange moving shapes you sometimes see in your vision, especially when looking at a bright, plain surface like a white wall or the sky, are known as “floaters.” Scientifically, they are called Muscae volitantes, which is Latin for “flying flies,” although they are not actual insects.

About 76 percent of people without visual impairments experience these phenomena. They usually look like tiny worms, specks, or threads that appear to drift across your field of view.

💡 The Cause of Floaters

Floaters are not on the surface of your eye but are actually small, real objects inside your eye.

They are tiny pieces of tissue, red blood cells, or protein clumps floating within the vitreous humor. The vitreous humor is the clear, gel-like substance that fills the large space between the lens and the light-sensitive retina at the back of your eye. Its purpose is to help the eye keep its round shape.

When light enters your eye through the lens, these small, floating objects cast shadows onto the retina. It is these shadows that you perceive as the peculiar, moving images we call floaters.

🌌 The “Opposite” Effect: Blue Field Entoptic Phenomenon

The text you provided also discusses a related, yet opposite, visual effect known as the blue field entoptic phenomenon.

Unlike floaters, which are shadows cast by objects in the vitreous, these “blue sky sprites” are created by structures in the retina itself. Specifically, this phenomenon is caused by white blood cells moving through the capillaries (tiny blood vessels) in the retina.

• How it Works: White blood cells are larger than red blood cells. As they pass through the small retinal capillaries, they can cause the red blood cells behind them to clump up and slow down.

• What You See: When you look at a bright blue background (like the sky), blue light is easily absorbed by red blood cells but passes right through the plasma and white blood cells. This means that as the white blood cells move, they create tiny, bright gaps followed by dark areas (the clumped red cells) that you can actually see drifting quickly in your vision.