Nontransparent material in the vitreous cavity casts a shadow on the retina; the closer the material to the tissue of vision, the more circumscribed (less fuzzy) the shadow. The visual disturbance is not objective; even more subjective is the way the individual’s brain processes it. Some people are bothered by a single, tiny floater; others do not recognize the presence even of those that the ophthalmologist can readily see at the slit lamp. Persons with synchysis scintillans (asteroid hyalosis) may have so many of these calcium or cholesterol bodies that the fundus is impossible to examine in fine detail (see Fig. 46.1), yet they do not complain and many of them decline surgery.