black eye floaters causes
1 Posterior uveitis is inflammation in the layers of the uvea in the back of the eye. Posterior uveitis, which can cause eye floaters, may be caused by infection or inflammatory diseases, among other causes.  Bleeding in the eye.
Eye floaters are those tiny spots, specks, flecks and cobwebs that drift aimlessly around in your field of vision. While annoying, ordinary eye floaters and spots are very common and usually aren't cause for alarm. Floaters and spots typically appear when tiny pieces of the eye's gel-like vitreous break loose within the inner back portion of the eye. Eye floaters can be clumpy or stringy; light or dark. They are caused by clumps or specks of undissolved vitreous gel material floating in the dissolved gel-like fluid (vitreous) in the back of the eye, which cast shadows on the retina when light enters the eye. Click on the image to see floaters in action.