Green light alleviates migraine photophobia (S47.005)

Objective: To determine the effects of color on headache intensity in migraineurs with normal eyesight and provide mechanistic explanation for the findings. Background: Exacerbation of headache by light is commonly associated with intracranial pathologies such as migraine, meningitis, concussion, and subarachnoid hemorrhage Design/Methods: Psychophysical methods were use to assess sensitivity to color during and in between migraine attacks. Electroretinography and visual evoked potentials were used to measure the magnitude of the electrical signals generated respectively by the retina and the cortex in response to different colors of light. Multi-unit recording in rats was used to study responses of thalamic dura-sensitive neurons to different colors of light. Results: Studying 69 patients, we found that (a) green light exacerbates migraine headache significantly less than white, blue, amber or red lights; (b) green activates cone-driven retinal pathways to a lesser extent than white, blue and red; (c) thalamic neurons are most responsive to blue and least responsive to green; and (d) cortical responses to green are significantly smaller than those generated by blue, amber and red lights. Conclusions: The study reveals a mechanism for the finding that exposure to green light exacerbates migraine headache significantly less than exposure to white, blue, amber or red lights in patients with normal eyesight. Taking into consideration results of ERG, thalamic and VEP recordings, the findings suggest that migraine photophobia may originate in the retina and fine-tuned in the thalamus, rather than in the cortex – a major shift in current thinking. Mechanistically, the psychophysical findings are explained by the differential responses of cone-driven retinal pathways, light-sensitive thalamic neurons in 2 sensory nuclei outside the main visual pathway, and the cortex to the different colors. Therapeutically, filtering out all but green light may prove beneficial for the reduction of photophobia and potentially the headache intensity. Study Supported by: NIH/NINDS grants R37 NS079678, RO1 NS069847, R21 NS090254-02, and K24 NS77895 Disclosure: Dr. Noseda has nothing to disclose. Dr. Reuven-Nir has nothing to disclose. Dr. Bernstein has nothing to disclose. Dr. Borsook has received personal compensation for activities with Vertex and Dermex. Dr. Buettner has nothing to disclose. Dr. Burstein has received personal compensation for activities with Allergan, GSK, and Merck as a consultant or member of the scientific advisory board.