Migraine sufferers have long complained about how their headaches worsen with bright light, and in case you ever doubted their complaints, Rami Burstein and other researchers from Harvard Medical School and the Moran Eye Center at the University of Utah recently made a giant step in understanding the light-to-headache mechanism in Nature Neuroscience. They found neurons in the rat thalamus sensitive to both light and to the dura (the membrane surrounding the brain). More intriguing than the “how” of light and headaches is the “why”. Why should light be linked with pain mechanisms at all? Why should the retina be in the business of eliciting pain in your brain?