There are black shadows in front of the eye, its various forms such as dusty, thread-like, cotton wool and lumpy, black dots in the eye movement is irregular floating, sometimes more and sometimes less, in the bright background is more likely to appear, generally does not affect vision, mostly seen in myopia and the elderly. Myopia more in 30 years of age, mainly vitreous liquefaction and basement membrane thickening, clinically known as mosquitoes; if the number of black dots suddenly increased within a few days, should be considered pathological vitreous clouding, but to exclude uveitis, retinitis, retinal detachment, intravitreal blood, retina or macula has appeared broken hole, so need to be a comprehensive examination. If simple mosquitoes, clinical examination in addition to vitreous detachment, often can not find vitreous clouding point, this no serious consequences, also do not need special treatment. If the examination does have obvious vitreous turbidity to actively treat.