Flying mosquitoes, or vitreous turbidity, is caused by vitreous degeneration, which is a natural aging phenomenon, that is, as we age, the vitreous body will liquefy and produce some cloudy material. Patients will appear black spots in front of the eyes, and will fly around with the rotation of the eye, as if flying mosquitoes, its shape has a round, oval, dotted, line, etc.. Flying mosquitoes often occur in middle-aged and elderly people over 40 years old, highly myopic patients, and those who have undergone cataract surgery, other patients such as intraocular inflammation or retinal vascular disease, can also form this disease. Most of the mosquitoes are benign, or “physiological mosquitoes”. Physiological mosquitoes can exist for a long time, unchanged throughout the year, does not affect vision, after examination there is no other eye pathology, usually if no major problems, can be ignored. But once there are flashes, flying mosquitoes suddenly increase, or appear to be obscured vision and other phenomena, poor vision, visual field defects and other symptoms, indicating that the vitreous body may be in acute degeneration, or the retina has the risk of hole, to quickly go to the ophthalmology examination of the retina, such as retinal detachment or vitreous hemorrhage, often need surgery or drug treatment.