What Causes Eye Flashes?
Ordinarily, light entering your eye stimulates the retina. This produces an electrical impulse, which the optic nerve transmits to the brain. The brain then interprets this impulse as light or some type of image. If the retina is mechanically stimulated (physically touched), a similar electrical impulse is sent to the brain. This impulse is then interpreted as a “flicker” of light. When the retina is tugged, torn or detached from the back of the eye, a flash or flicker of light commonly is noticed. Depending on the extent of the tear or detachment, these flashes of light might be short-lived or continue indefinitely until the retina is repaired. Flashes (photopsia) also may occur after a blow to the head, often called “seeing stars.” Some people experience flashes of light that appear as jagged lines or “heat waves” in both eyes, often lasting 10-20 minutes. These types of flashes are usually caused by a spasm of blood vessels in the brain, which is called a migraine. If a headache fol
