If you have a flashing sensation in your eye, then a posterior vitreous detachment may have occurred. The vitreous body is the innermost clear, jelly-like thing in the eye, and it is mainly composed of collagen fibers and sodium hyaluronate. The vitreous humor is gradually liquefied from the age of 6 and collapses from the middle to the middle. When the surrounding vitreous humor and the retina are tightly attached, the collapse to the middle pulls the attached retina, causing the retina to discharge abnormally, which makes people feel like they have a flashing sensation in front of their eyes. However, if it is accompanied by a large number of black shadows in front of the eyes or a curtain-like blocking sensation in front of the eyes, or if there is a deformation of vision and a sudden loss of vision, please consult a doctor promptly as a retinal fissure or retinal detachment may have occurred.