The appearance of black filaments in the eyes may be a sign of fundus disease, so it is important to go to the hospital as soon as possible to have a fundus examination to determine the cause of this condition. The cause of this condition may be vitreous disease or retinal disease, such as vitreous turbidity, vitreous blood, retinal fissure, retinal detachment, etc. These diseases may lead to the appearance of this symptom. Different diseases are treated differently: if it is a physiological vitreous turbidity, which is commonly known as mosquitoes, this situation does not need to be dealt with, and will not affect vision; if it is vitreous hemosiderosis or retinal fissure, retinal detachment, these pathological diseases, then we must actively treat to avoid aggravation of the disease to cause more serious effects.