A watery flashing sensation appears in the eyes. It returns after a while, which may be due to either physiologic or pathologic factors. 1. Physiologic factors: In physiologic posterior vitreous detachment, with age, most patients over 70 years old will experience separation of the posterior vitreous membrane from the inner retinal membrane. In the process of separation, the posterior vitreous membrane will have an impact on the retina, and the patients will show the phenomenon of eye flashes and water ripples. 2. Pathologic factors: watery eyes and flashing sensation are mostly caused by posterior vitreous detachment. Posterior vitreous detachment is often manifested as water ripples in front of the eyes, flashing sensation, at the same time, there will be a cobweb-like black shadow in front of the eyes floating. Microscopic examination can see a ring-shaped dense ring, for the vitreous body and optic nerve papilla attachment part of the tear caused. Patients feel eye discomfort, need to go to the hospital as soon as possible to confirm the diagnosis, follow the doctor’s instructions for standardized treatment. Patients should pay attention to rest more often, do not overwork.