Floater

Floaters or eye floaters are small dots in the field of vision of a person. They are transparent and between the eye's vitreous humour or between the vitreous and retina. Their medical name is "muscae volitantes" (Latin for 'flying flies'), or "mouches volantes" (French for 'flying flies'). All people will get them over time, but not all will notice them. Nearsighted people can notice them earlier. It might be possible to get these by debris falling into the eye. 
Origin.
The vitreous, a jelly-like material inside the eyeball, becomes more liquid. This happens when people age. But young people can also get them. When this happens, small collagen fibers and vitreous form to clumps. These clumps throw shadows onto the retina. These shadows are floaters.
Treatment.
Laser vitreolysis is a possible treatment option for the removal of floaters.