There are many reasons for sudden watery flashes before the eyes, including physiologic posterior vitreous detachment, pathologic retinal pull, and visual fatigue. 1. Physiologic posterior vitreous detachment: With the increase of age, the separation between the posterior vitreous membrane and the inner border membrane of the retina occurs, and the patient may suddenly have the feeling of water ripples in front of the eyes, which is a physiologic phenomenon and usually requires no treatment, and can be observed by regular follow-ups. 2. Pathological retinal pulling: due to high myopia, retinal degeneration and other causes of retinal pulling, affecting the normal visual function, there will also be rippling flash in front of the eyes, usually need to carry out funduscopic examination to clarify the cause of the disease, and then treat the cause of the disease. 3. Visual fatigue: long-term late at night, excessive eye use will stimulate the eyes to produce a sense of dryness, triggering visual fatigue, making the eye muscle spasms, affecting vision can also appear watery flashes, this situation is recommended to take a rest, follow the doctor’s instructions to give the appropriate to improve the circulation of medicines such as seven leaves of digitalis bisabololol eye drops, and so on. When the watery flashes in front of the eyes are not relieved for a long time, it is recommended to go to the local hospital as soon as possible for examination, to clarify the cause of the disease, and then follow the doctor’s instructions to deal with it.