People with migraines also are also typically aggravated by light with worsening of symptoms compared to being in the dark. This causes many migraine sufferers to wear sunglasses, often at night, Burstein says.
It was the observation that even blind people who suffer migraines were experiencing sensitivity to light, referred to as photophobia, that led Burstein and Rodrigo Noseda, PhD, to hypothesize that signals transmitted from the retina to the optic nerve were triggering the intense headaches, the authors say.
The scientists studied two groups of blind people with migraines. Patients in one group were totally blind because of eye diseases, unable to see images or sense light.
People in a second group were legally blind, but were able to detect the presence of light.
“While the patients in the first group did not experience any worsening of their headaches from light exposure, the patients in the second group clearly described intensified pain when they were exposed to light, in particular blue or gray wavelengths,” Burstein says in a news release. “This suggested to us that the mechanisms of photophobia must involve the optic nerve, because in totally blind individuals, the optic nerve does not carry light signals to the brain