What you are seeing are commonly called "floaters." Everybody has them. They're nothing to worry about, unless you happen to notice them increasing in number.
Originally posted by wiki:
Floaters are deposits of various size, shape, consistency, refractive index, and motility within the eye's normally transparent vitreous humour[1]. They may be of embryonic origin or acquired due to degenerative changes of the vitreous humour or retina[1]. The perception of floaters is known as myodesopsia, or less commonly as myiodeopsia, myiodesopsia, or myodeopsia[1]. When observed subjectively, floaters are entoptic phenomena characterized by shadow-like shapes which appear singly or together with several others in one's field of vision. They may appear as spots, threads, or fragments of cobwebs, that float slowly before one's eyes.
