The flashing sensation in the eye is usually caused by a posterior vitreous detachment, which may take a month to a year to gradually heal in some patients, but in others it never heals.
Posterior vitreous detachment is a common ophthalmic condition, usually due to aging factors. It is caused by the loss of support after the vitreous body liquefies, thus separating the posterior vitreous border membrane from the retina. In the process of separation, it will pull and stimulate the retina to cause flash sensation. When the posterior vitreous detachment is completed, there will be no more pulling on the retina, and the flash sensation will disappear naturally.
It usually takes one month to one year from the onset of posterior vitreous detachment to the completion of posterior vitreous detachment, and some patients will gradually recover from the detachment, but there are some patients whose posterior vitreous detachment will not be completely detached, and the flashes of light will persist for a long period of time. If the flashing sensation worsens suddenly within a short period of time or is accompanied by a sensation of blocked vision, a medical examination should be performed to rule out the possibility of other fundus lesions.