A special pair of sunglasses could one day help ease symptoms in those that suffer the agony of the crippling migraines. The idea hinges on the discovery that a narrow beam of green light could provide relief to those struck by the painful headaches. A new study reveals pure green light can also reduce the intensity of a person’s migraine. Light sensitivity, or photophobia, is a frequent symptom of migraine headaches, which affect nearly 15 percent of the world’s population. But researchers found that green light significantly reduces light sensitivity and can reduce the severity and pain of a headache. Thus sunglasses that block all but a narrow band of pure green light could prove a means of treating the common affliction. Dr Rami Burstein lead author and academic director at the Comprehensive Headache Centre at the Beth Israel Deaconess Medical Centre, said, “Although photophobia is not usually as incapacitating as headache pain itself, the inability to endure light can be disabling. More than 80 percent of migraine attacks are associated with and exacerbated by light sensitivity, leading many migraine sufferers to seek the comfort of darkness and isolate themselves from work, family and everyday activities.” A new study, led by researchers at Harvard Medical School and the Beth Israel Deaconess Medical Centre found that exposing migraine sufferers to a narrow band of green light significantly reduces photophobia and can reduce headache severity. Researchers asked patients experiencing acute migraine attacks to report any change in headache when exposed to different intensities of blue, green, amber and red light. At high intensity of light – such as a well-lit office – nearly 80 percent of patients reported intensification of headache with exposure to all colours but green. They found that green light even reduced pain by about 20 percent. Dr Burstein added, “These findings offer real hope to patients with migraines and a promising path forward for researchers and clinicians.” Along with his colleagues, Dr Burstein and the team designed experiments in which they measured the magnitude of the electrical signals generated by the retina in the eye and the cortex in the brain of these patients in response to each colour of light to discover why green light causes far less pain to patients with migraines. Five years ago, Dr Burstein and colleagues made the surprising discovery that blue light hurts migraine patients who are blind. However, because that study involved only blind patients, who cannot detect all colours of light, Dr Burstein and his colleagues devised a way to study the effects of different colours of light on headache in patients without visual impairment. This finding led to the thinking that abnormal sensitivity to light during migraine could be alleviated by blocking blue light. Researchers are now working to develop a more affordable light bulb that emits ‘pure’, or narrow band wavelength, green light at low intensity, as well as affordable sunglasses that block all but this narrow band of pure green light.