Migraines are not only characterized by severe headaches, but many sufferers also suffer from extreme sensitivity to light. However, scientists at Harvard Medical School have now found that a certain range of green lights are not affected and that this light can even reduce migraine headaches.
According to the researchers, around 15 percent of the world's population suffer from migraine headaches, which are often exacerbated by light and associated with extreme sensitivity to light. Many sufferers therefore withdraw to a darkened room until the acute attack is over. However, the research team led by Rami Burstein from Harvard Medical School was able to prove in its current study that exposure to a narrow spectrum of green light reduces sensitivity to light and headaches. The researchers published their results in the specialist journal "Brain".
Relationship between sensitivity to light and migraines
The researchers explain that more than 80 percent of migraine attacks are related to light sensitivity and are intensified by it. "Many migraine patients are therefore looking for the comfort of darkness and isolate themselves from work, family and everyday life," says study leader Burstein. Although the sensitivity to light is usually less stressful than the headache itself, the inability to endure light can also severely restrict those affected.
Even blind migraine sufferers react to blue light
Five years ago, the researchers came across the surprising discovery that blue light causes a reaction even in blind migraine sufferers. So they came up with the idea that the abnormal sensitivity to light in migraine patients could be alleviated by blocking the blue light. They continued to investigate patients who could not recognize all colors of light and "developed a way to study the effects of different colors of light on headaches in patients with no visual impairment," the Havard Medical School said in a press release of the study results.
Green light pain reduced by 20 percent
As part of their current study, Burstein and colleagues found that the condition of migraine sufferers worsened in all colors of the light spectrum, except for a narrow spectrum of green light. With high intensity of light, such as in a well-lit office, almost 80 percent of patients complained of an intensification of the headache - for all colors, except green, according to the Harvard Medical School. In low intensities, the special range of green lights even alleviated the headache. The pain decreased by around 20 percent.
Different signal strength in the brain
In order to understand the effect of green light on migraine patients, the researchers measured the strength of the electrical signals generated by the retina (in the eye) in the different colors and the response of the cerebral cortex (in the brain) to each in special experiments Color of light determined. They found that blue and red lights generated the largest amount of signals - both in the retina and in the cortex. On the other hand, green light has triggered the smallest signals. There were also differences in signal transmission in the thalamus. The neurons in the area of the brain that carries the information about the light from the eye to the cortex reacted fastest to blue light and slowest to green light, the researchers report. This could explain why migraine patients respond positively to the green light.
Hope for therapeutic uses
The new findings "offer real hope for patients with migraines and a promising path for the future," emphasizes study leader Rami Burstein. For example, the scientists are already working on developing an inexpensive light bulb that emits "pure" (narrowband wavelength) green light at low intensity. So far, according to the researchers, the cost of a corresponding light bulb has been prohibitively high. Inexpensive sunglasses that block the entire light spectrum apart from the narrow range of pure green light are already in the planning stage. But the technology to block everything except pure green light with sunglasses is only available in light microscopy, which is also very expensive. In the long term, the scientists believe that the use of green light could be a very attractive treatment for migraines. (fp)