Why do I see floaters in my vision?

Floaters in your vision are caused by tiny fibers or cells floating in the vitreous gel inside your eye. These floaters cast shadows on your retina, which you perceive as small, dark spots or lines in your field of vision. They are usually harmless, but if you notice a sudden increase in floaters or flashes of light, it may indicate a more serious eye condition and you should see an eye doctor.