In general, the sudden watery eyes of patients may be caused by physiologic posterior vitreous detachment or retinal detachment, etc. Whether it is dangerous or not is related to the patient’s condition. Physiologic posterior vitreous detachment can lead to sudden watering of the eyes because the detached vitreous body involves the retina. Because physiologic posterior vitreous detachment is a normal aging phenomenon that does not affect the patient’s vision, it is usually not dangerous and can be left untreated and followed up for observation. If the posterior vitreous detachment significantly involves the retina, it may lead to retinal tears or even retinal detachment, resulting in the sudden appearance of water ripples in the patient’s eyes. Because retinal detachment can significantly damage the patient’s vision, it is more dangerous and the patient needs to seek prompt medical attention to improve the eye discomfort. It is recommended that patients with watery eyes and visual impairment seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.