A lightning or flashing sensation in the eye is usually due to retinal shock caused by pulling on the vitreous, resulting in visual sensitivity problems. It is more common in myopic eyes or in middle-aged and elderly people, and is caused by degenerative changes in the vitreous body, causing posterior vitreous detachment, which pulls on the retina at the base of the eye and causes retinal shock at the base of the eye, resulting in an abnormal response to visual function. This type of lightning and flashing sensation is an indication of retinal traction in the eye. Once this happens, you need to go to the hospital for a fundus examination in time, because the retinal fissure is caused by the uneven force during the traction process, leading to an increased risk of retinal detachment. Retinal detachment is a very serious disease that can lead to visual field defects and even vision loss. If treatment is not timely, it is difficult to restore vision and visual field even if detachment resetting is performed. A sensation of flashing light or lightning in the eye requires prompt medical attention to rule out peripheral retinal fissures, and if there are fissures they need to be treated aggressively to prevent retinal detachment.