Flying mosquitoes is a common outpatient disease, and is also very common in the normal population. So, what is the cause of mosquito flying syndrome, and should we treat it? Flying mosquitoes is due to the eye’s vitreous body (the transparent jelly-like part of the back of the eye) within a variety of cloudy, when the light will have a shadow on the retina, that is, flying mosquitoes. The vast majority of people with vitreous clouding are caused by age (generally after the age of 40) that causes the vitreous to liquefy and the colloid to become uneven. Nearsightedness and trauma can bring this change forward. There are also some of the flying mosquitoes are caused by age-induced posterior vitreous detachment (separation of retina and vitreous body), because posterior vitreous detachment is a physiological phenomenon, so it usually does not need to be treated. However, in a few patients the vitreous process can lead to retinal tears, which in turn can cause retinal detachment. There are also some retinal vascular diseases that cause a small amount of vitreous hemorrhage that can also manifest as flying mosquitoes. If the hemorrhage is large, it can lead to a great loss of vision. In addition, uveitis can also lead to clouding of the vitreous, which can cause mosquitoes. If mosquitoes appear, you need to see a fundus specialist for a detailed examination of the fundus to rule out retinal hemorrhages, fissures and detachments. If it is just ordinary mosquitoes, generally do not need to deal with. Theoretically therapeutic drugs are clinically observed to have limited effect. Therefore, the main is the psychological adjustment, to avoid repeated entanglement with mosquitoes and lead to mental stress.