Study: How One Particular Light Color Relieves Migraine

Photophobia or sensitivity to light is a well-known symptom of migraine headaches. Light is known to cause excruciating and unbearable pain, but a new study shows that not all color of life can exacerbate migraines. In fact, one particular color of light might even reduce the severity of headaches caused by migraine.

The study, published in the journal Brain, suggests that exposing a patient with acute migraine to pure-wavelength of green light exacerbates migraine significantly less than all other colors of light and can even reduce the headaches at low intensities.

For the study, researchers exposed 41 participants experiencing acute migraine attacks to different intensities of blue, green, amber and red light. They asked the participants to report any change in headache during the exposure.

Among the 41 participants, 80 percent reported intensification of headache with exposure to all colors of high intensity of light, except green. Surprisingly, the researchers also found out that exposure to green light reduced pain 20 percent.

To further understand the link between green light and its effect to patients with migraine, researchers designed an experiment measuring the magnitude of electrical signals generated by the retina (in the eye) and the cortex (in the brain) in response to each color of light. They found out that the largest signals in both the retinas and the cortex were generated by blue and red lights, while the smallest signals were generated by green light.

Additionally, researchers also analyzed the neurons found in the thalamus using animal models of migraine. Thalamus is the area in the brain responsible for transmission of information about light from the eye to the cortex. Researchers discovered that neurons in the thalamus are most responsive to blue light, but least responsive to green light, explaining why the migraine brain responds favorably to green light.

With their findings, researchers are now trying to develop a more affordable light bulb that emits pure narrow-band wavelength of green light and sunglasses that can block out all colors of light except narrow band of pure green light.