Momentary flashes of light across a person's vision is called photopsia. Normally, light enters the eye and causes the retina in the back of the eye to communicate with the brain via the optic nerve. However, flashes of light appear in vision if the retina is physically disturbed or if other things disrupt the transmission of signals between the retina and the brain.
Retinal Detachment
The School of Medicine at the University of Utah describes the retina as being .5mm thick and lining the back of the eye. The sensitive tissue in the retina sends messages to the brain via the optic nerve. If the retina tears or comes off the back of the eye, flashes of light can be seen. Retinal detachment is caused by a sudden blow to the head, from eye surgery complications and deterioration of the eye from aging. Early detection and prompt treatment is essential. Retinal detachment is treated with laser and by surgery, depending on the type and severity of the tear.
Migraines
Migraines typically refer to severe headache pain that is usually caused by a blood vessel spasm in the brain. Flashes of light in the eye sometimes accompany migraines. However, it is possible to have flashes of light without the head pain. In this instance, the migraine is called an ophthalmic or ocular migraine, according to the Merck Manual.
Digitalis Side Effect
Some heart patients take a medication called digitalis. Too much of the medication, called digitalis toxicity, results in complications such as visual problems. Seeing flashes of light one of the symptoms associated with taking too much digitalis, either over time or in one single dose, according to the National Library of Medicine.
