Flashes are commonly described as lightning streaks, stars, or flashing lights in the outside edges (periphery) of the eye. Flashes are caused by the vitreous pulling on the retina and stimulating your photoreceptors, which in turn creates a flash.
Flashing lights may be a symptom of a retinal detachment or a retinal tear. If you are experiencing flashes, it is important to consult your eye doctor quickly as an untreated retinal detachment can lead to irreversible blindness.
If a retinal tear has developed but the retina has not yet detached your retinal specialist will treat the retinal tear with laser retinopexy or cryotherapy. Both of these treatments cause a scar to develop around the retinal tear which prevents the retina from detaching.
Flashes may be accompanied by the presence of floaters – small shapes that appear as dark dots or thread-like shapes in your vision. Because the retina does not contain pain receptors these symptoms are painless.