Many of us often find that when looking at bright places, white walls and blue skies, you can see bugs and thread-like things flying in front of your eyes, and feel and sight moving together, blinking does not disappear, but in the dark places will not feel. This feeling of “floating objects” in front of the eyes is called “flying mosquitoes”. For most older people, this is the normal physiological aging of the vitreous humor of the eye. The vitreous humor is an egg-white-like clear gel. When people are young, the vitreous remains uniform gel, but after the age of 40, the gel-like vitreous gradually formed watery, liquefied space, with the rotation of the eye and shaking, so that the retina is stretched and the formation of dark shadows in front of the eyes. This symptom, which occurs during vitreous aging, usually does not affect vision. However, there are several conditions that need attention and may affect vision. One is vitreous inflammation, the other is blood accumulation in the vitreous, and the third is parasitic invasion of the vitreous. Therefore, if you find a black shadow floating in front of your eyes, you should immediately go to an ophthalmologist for a detailed examination. There is one more point to pay special attention to, that is, people with high myopia, if more black shadows in front of the eyes, but also accompanied by flashes or feel vision loss, may be a signal of serious intraocular pathology, should be dealt with after the examination. Flying mosquitoes in the medical divided into physiological flying mosquitoes and pathological flying mosquitoes. 1, physiological mosquitoes can generally be divided into the following three kinds: congenital physiological mosquitoes; elderly physiological mosquitoes; myopic physiological mosquitoes. On the basis of eye examination, these three types of mosquito flying disorder once diagnosed, and there is no certain treatment necessary. 2, pathological mosquito flying can suggest the following diseases: retinal fissures and retinal detachment. Due to posterior vitreous detachment as well as other reasons, fissures can appear in the retina and allow liquefied vitreous to seep into the fissures, thus leading to retinal detachment. Therefore, the initial symptom of retinal detachment is a dramatic increase in the number of “floaters” in front of the eyes, for this pathological mosquito flying, if left unchecked will lead to blindness. In general, retinal tears can be treated by laser coagulation around the tears (laser coagulation) to prevent retinal detachment, which can be treated on an outpatient basis; if retinal detachment has occurred, hospitalization and surgery are required. Vitreous hemorrhage, diabetes, hypertension and ocular trauma can cause fundus hemorrhage, in which case, once the blood enters the vitreous it can suddenly feel the symptoms of flying mosquitoes or the sensation of a red curtain seeming to be drawn before the eyes. Depending on the amount and location of bleeding, it can cause different degrees of vision loss. In this case, if the bleeding is small can be self-healing, generally treated with hemostatic drugs and drugs to promote blood absorption. However, depending on the condition, laser and surgical treatment may also be used. In addition, the result of one examination does not equal to no problem forever. As soon as there are flashes of light (similar to welding light), a sudden increase in dark shadows, or obscured vision, it is important to go to the hospital for detailed examination.