Migraines could be caused by a sufferer"s sensitivity to light, and wearing sunglasses may be the answer to ease the pain, say scientists.
Research carried out at Harvard Medical School found that even the tiniest bit of light that can get through closed eyelids can cause migraines.
The scientists studied two groups of blind people who suffered from migraines and found that light sensitivity was closely linked to the condition.
This led them to the conclusion that impulses from the eye to the brain may be what triggers the pulsing headaches.
Professor Rami Burstein, from Beth Israel Deaconess Medical Centre, in Boston, and Harvard Medical School, said: "This helps explain why patients say that their headache intensifies within seconds after exposure to light, and improves 20 to 30 minutes after being in the dark."
He added: "Migraine patients may benefit from wearing sunglasses, even at night."
by Adrian Galbreth