Scintillating scotoma, also called flickering scotoma or visual migraine, is the most common visual aura preceding migraine. Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. The affected area flickers but is not dark. It then gradually expands outward from the initial spot. Symptoms typically appear gradually over 5 to 20 minutes and generally last fewer than 60 minutes, leading to the headache in classic migraine with aura, or resolving without consequence in acephalgic migraine
Scintillating scotomas are most commonly caused by cortical spreading depression. The assumed mechanism should lower the cortical threshold for spontaneous excitation.
The Framingham Heart Study (published in 1998) found that scintillating scotomas without other symptoms occurred in 1.23% of the group. The study did not find a link between late-life onset scintillating scotoma and stroke.