Migraine sufferers are extra sensitive to flickering lights starting at an early point in the visual pathway, York University researchers have found.
Professor Frances Wilkinson and her co-researchers Michel Thabet, Professor Hugh Wilson and Olivera Karanovic reported in the January 2013 issue of Cephalalgia that individuals who are not affected by migraines showed gradual adaptation or reduced 
sensitivity to an intense flickering light, while sensitivity increased with repetition for individuals prone to migraine headaches, even though they were tested in a headache-free period.
Frances Wilkinson
“The abnormality was either just at the point where the information is conveyed into the visual cortex or at an earlier point on the pathway from the retina to the visual cortex — either in the thalamus or in the retina itself,” explains Wilkinson, leader of the research team that was funded by the Canadian Institutes of Health Research (CIHR). A combination of behavioural testing and neural network modelling was used to establish this finding.
“Identifying the sites of the abnormal sensitivity in the visual and other sensory systems is an important step toward developing more targeted drug treatments for migraine,” she adds.
The research is very relevant with respect to the design of lighting. Even lights flickering at very high rates, which are not consciously visible, may affect the visual system of those affected by migraines.
With the rapid, ongoing change in lighting technology — such as the increasing use of LEDs — it is all the more important to understand how light affects the visual system of those suffering from migraines to help design built environments that are more migraine-friendly. Close to three million Canadians, primarily women of working age, suffer from migraine headaches.