Meaning of "floater" in the English dictionary

Floaters are deposits of various size, shape, consistency, refractive index, and motility within the eye’s vitreous humour, which is normally transparent. At a young age, the vitreous is transparent, but as one ages, imperfections gradually develop. The common type of floater, which is present in most people’s eyes, is due to degenerative changes of the vitreous humour. The perception of floaters is known as myodesopsia, or less commonly as myodaeopsia, myiodeopsia, myiodesopsia. They are also called Muscae volitantes, or mouches volantes. Floaters are visible because of the shadows they cast on the retina or refraction of the light that passes through them, and can appear alone or together with several others in one’s visual field. They may appear as spots, threads, or fragments of cobwebs, which float slowly before the observer’s eyes. Since these objects exist within the eye itself, they are not optical illusions but are entoptic phenomena.