Eyes floating black shadow is considered the cause of vitreous turbidity, vitreous turbidity is also known as mosquitoes, the main clinical manifestation is a black dot or black line in front of the eyes, like flying mosquitoes, so called mosquitoes. Its formation is mainly due to the transparent vitreous body appears opaque impurities, and impurities projected on the retina shadow, the formation of the feeling of a black shadow in front of the eyes. Vitreous turbidity is a normal physiological phenomenon, if not accompanied by other ocular organic pathology, there is no clinical significance of treatment. In principle, vitreous clouding can be divided into physiological and pathological, physiological vitreous clouding is a physiological phenomenon that grows with age and does not require treatment. In the case of pathological vitreous clouding, if a large number of black shadows appear within a short period of time, it is necessary to go to the hospital for further treatment.