With SVG we can add a clipping path to change the shape of our images. First we open a SVG tag with namespaced href attribute and namespace definition: <svg class=svg-graphic width=180 height=200 viewBox=0 0 560 645 xmlns=http://www.w3.org/2000/svg xlink=http://www.w3.org/1999/xlink version=1.1>.
Just as with other types of migraine, the underlying cause for migraines with visual symptoms have not been definitively established. Many researchers believe that these symptoms are caused by a short-lived reduction in blood flow, which might be caused by a spasm in the blood vessels.
One leading theory for the cause of migraines is âcortical spreading depression.â This wave of brain activity that sweeps over the brain, can be seen on an MRI and is blamed for migraine aura and other migraine symptoms. Others believe hyperactivity in the brain stem causes migraines. Because migraines are difficult to control, many people with this disorder often take medication regularly. Overuse of medication can also lead to migraines.