Floaters are due to the abnormal presence of opacities of varying density and morphology in the vitreous.
Under certain lighting conditions, their shadow is projected onto the retina and their image is superimposed on that of the objects being viewed. These artefacts are always mobile. They move in the visual field with some delay during eye movements (just like sediment in a bottle when it is shaken). Quite commonly seen, these floaters do not have pathological value when they are few in number. No treatment can make them disappear.
However, their sudden appearance or increase in number should draw attention, especially if the phenomenon is accompanied by flashes of light. In this case, a fundus examination by an ophthalmologist must be carried out as soon as possible. These floaters may indeed be the consequence of intraocular hemorrhage and/or detachment of the vitreous. The latter can be the cause of a serious complication: retinal detachment (see "retinal detachment").