Muscae volitantes or floaters are moving vitreous opacities perceived when they cast a shadow on the retina. So they are more noticeable against a bright background.
They may be perceived by the patient as black dots, rings, strands or spider webs and keep on moving even when the head is still. Vitreous is normally transparent but when some processes cause degeneration and liquefaction of the vitreous it produces floaters.
The various causes of floaters are :
