Floaters: generally caused by vitreous degeneration, is a natural aging phenomenon, that is, as we age, the vitreous body will “liquefy”, producing some cloudy material. Therefore, the official name of mosquito flying disease is “vitreous chaos” or “vitreous floaters”. See the black spot flying in front of the eye, as if flying mosquitoes so named. Flying mosquitoes is intravitreous opaque objects projected on the retina produced. In bright light or white background, more obvious. Sensitive people can even depict them in a variety of different shapes. Many mosquitoes exist for a long time, unchanged throughout the year, do not affect vision, after examination there is no ocular pathology, there is little clinical importance, no need to worry about. Some older people suddenly appear one or two black shadow in front of the eyes without other symptoms, often due to the vitreous membrane detachment, and generally not much harm. However, if a large number of black dots suddenly appear, one should think of retinal vascular rupture and bleeding or retinal fissure formation, which may be a precursor of retinal detachment, and further detailed examination of the fundus should be performed. Choroiditis when many sex-like cells or exudates can enter the vitreous, is also a common cause of pathological flying mosquitoes, but often because of the simultaneous presence of visual impairment and not easily detected. Myopic patients feel the flying mosquitoes, often related to the vitreous liquefaction degeneration. Flying mosquitoes often occur in middle-aged and older people over 40 years of age, highly myopic patients, and those who have had cataract surgery, other patients such as intraocular inflammation or retinal vascular disease, can also form this disease. Most of the mosquitoes is benign, or “physiological mosquitoes”, its characteristics are: if patients have mosquitoes in both eyes, it is impossible to determine which eye has mosquitoes, if after a period of time, these phenomena do not aggravate or produce changes, mosquitoes also fixed location, more for benign. On the contrary, if the phenomenon of flying mosquitoes occurs suddenly, and limited to one eye, the direction of mosquitoes flying and unpredictable, black shadows obscure the field of vision, poor vision, visual field loss, this is a must pay attention to the bad signs. The following is a summary of several dangerous symptoms of mosquito flying disease: (1) there are abnormal flashes. (2) Increasing number of flying mosquitoes in a short period of time. (3) A feeling of blocked vision. As a few flying mosquitoes is a sign of serious disease, so experts believe that if you find a flying mosquitoes dancing in front of your eyes, you should first make a specialist examination, after examination, in case there is unfortunately a serious eye disease, then we should target the eye disease treatment. But the results of a checkup is not the same as no problem forever. Once there are flashes, flying mosquitoes suddenly increased, or appear to be obscured vision and other phenomena, it is necessary to immediately receive a detailed examination again. Flying mosquitoes refers to a small floating black shadow in front of the eyes, especially when looking at a bright white background symptoms are more obvious, may be accompanied by a sense of flash. Vitreous liquefaction and posterior dislocation are the main causes of mosquito flying. 70% of patients have this, but 1/4 of patients may have vision-threatening lesions, the main one being retinal fissure formation. When you see mosquito flying, you should dilate the pupil and examine the fundus carefully, including slit lamp trichoscopy, only posterior vitreous detachment does not need special treatment, the lesions that have a risk to vision should be treated according to the relevant principles. Intraocular inflammation caused by flying mosquitoes, feel the black shadow in front of the eyes more dusty or flocculent, vision can have different degrees of impact, examination under the glass body with dusty, flocculent floaters, slit lamp triple microscopy can be seen in the peripheral choroidal inflammation caused by exudation, vascular white sheath and other pathological changes. Intraocular hemorrhage caused by flying mosquitoes feel in front of the eyes such as smoke clouds moving or ink-like downstream black shadow, individual red or orange floaters, examination glasses or slit lamp to see the intravitreal thickness of the flakes, flocculent, clumps of hemorrhage and see the primary retinal lesions causing hemorrhage. Hemorrhages due to posterior vitreous detachment traction vessels are often associated with retinal fissures and should be noted.