Floaters can go away when gravity pulls them down below the line of sight. They come back when something shakes up the fluids of the eye, raising them back into the field of vision. Almost everyone sees floaters at one time or another. Your vitreous floaters can have varying degrees of significance, depending on what causes them. A floater can be a few clumps of cells, a collapsed vitreous, a piece of tissue torn from the retina, or even blood cells floating in the vitreous.
Most floaters are harmless.
They usually represent some cells or strands of the vitreous jelly that have harmlessly clumped together so that they are less transparent than the rest of the vitreous. However, there are more significant causes for floaters. The mass of the vitreous jelly can liquefy. This commonly happens, as we get older. Eventually this thinned out jelly can collapse pulling the membrane that surrounds it away from the retina.