Research on Migraines and Light Sensitivity

If you suffer from migraines, you surely know how debilitating its effects can be on any given day. Migraines often cause people to suffer from throbbing pain in one part of the head, vomiting, nausea, and other symptoms. They effect almost thirty million people in the United States and can result in the filing of disability paperwork, due to the difficulty that people have in engaging in work and daily activities. It can be difficult to predict when a migraine is going to occur and it is even more difficult to control once one happens. One of the most exacerbating factors for a migraine is light, which makes many people retreat to a dark room when a migraine hits. Now researchers believe they know the reason that light is such a powerful contributor to the condition.

This new research has found that there is a visual pathway in the brain that underlies light sensitivity during migraines in blind people and in those with normal eyesight. The hope is that with identification of this pathway, certain treatments may be developed to block the pathway so that individuals can be in the light without suffering pain. More research will be needed, as the recent experiments were only conducted on rats, which do not always translate into helpful therapies for humans.

The impetus for the experiment was that approximately eight-five percent of migraine sufferers also have extreme sensitivity to light, which is known as photophobia. Interestingly, even blind individuals exhibit photophobia, which led the researchers to believe that the retina transmitted signals along the optic nerve that somehow triggered an intensification of pain. Scientists explored this phenomenon further by examining two groups of blind human patients who suffered with migraine headaches. The first group consisted of individuals who were totally blind and could not see images or sense light, while the second group consisted of individuals who were legally blind due to degenerative diseases and could not see images, but could sense light. The team found that those who were blind and couldn’t see light did not have increased migraine pain when exposed to light, however the second group, who could sense light, described more pain.

After this examination, the scientists concluded that photophobia must involve the optic nerve because the optic nerve does not send light signals to the brain in totally blind individuals. Further, the scientists realized that the second group did not have normal sleep-wake cycles, which are controlled by light. Therefore, they opined that retinal cells which dictate biological cycles, such as sleep, also dictate the light sensitivity phenomenon.