If you are seeing flashing lights in your vision, you are probably suffering from a vitreous detachment. This is when the vitreous jelly inside the eye contracts and peels off the retina. Many people describe seeing a flash like a “streak or arc of lightening” in their peripheral vision. While a vitreous detachment is relatively benign, those flashes can be the harbinger of more serious problems like a retinal detachment. Another cause for a “flash” is a migraine aura … this is a special kind of headache that causes lights or waviness to the vision. These aren’t truly flashes, however, as they usually persist for 15-30 minutes. New flashes warrant a dilated eye exam to rule out retinal problems.