Retinal detachment is one of the more serious ophthalmic diseases that threaten vision and has a poor prognosis. Therefore, early detection and treatment are essential for the recovery of vision. In the early stages of detachment, there are a number of precursory symptoms that may prevent the disease from occurring if timely treatment is taken. A typical precursor symptom is mosquito flying with a flashing sensation. In people at high risk for retinal detachment, such as patients with high myopia and the elderly, most of them will themselves be accompanied by vitreous clouding to the cause of mosquitoes, but the difference is that retinal detachment precursors of mosquitoes, is sudden, and rapid development. It is accompanied by a lightning-like flash in the eye. The flash is generally due to the retina receives different causes of stimulation and produces the retinal cell automatic discharge phenomenon. When this occurs, it is important to take it seriously and come to the hospital this morning for a fundus examination, and, be sure to dilate the pupil for examination in order not to miss the diagnosis. If retinal fissures are detected and treated with laser to close the fissures in time before the extensive retinal detachment, the subsequent retinal detachment can be prevented without the pain of surgery. For other types of retinal diseases, early treatment can prevent retinal detachment, such as diabetic retinopathy and gestational hypertensive retinal disease, early identification of the fundus and early intervention to control blood sugar and blood pressure can prevent retinal detachment. Therefore, retinal detachment may be secondary to the development of a fissure, or it may be secondary to some eye disease or systemic disease. Early screening, early diagnosis, and treatment of the primary disease is the key.