From stripy sofas to brutalist buildings, patterns of parallel lines found everywhere could be bringing misery to millions of headache sufferers, according to Dutch scientists.
While the link between flashing lights and certain forms of epilepsy is well known, some static patterns made up of bars and lines are now suspected of causing negative effects even in the brains of healthy people.
Researchers at the University Medical Centre (UMC) Utrecht in the Netherlands say a rise in a type of brain activity seen when such images are viewed indicates a possible cause of headaches.
The UMC researchers say that grating patterns produce strong "gamma oscillations", while others like cloudscapes or natural scenes do not.
Around one in five women and one in 15 men suffer from migraines in the United Kingdom, costing the economy an estimated 25 million working days per year.
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The team behind the research said their findings could be taken into account by architects and designers in order to help those sensitive to migraines.
"Our findings imply that in designing buildings, it may be important to avoid the types of visual patterns that can activate this circuit and cause discomfort, migraines, or seizures," said Dora Hermes of the UMC.
"Even perfectly healthy people may feel modest discomfort from the images that are most likely to trigger seizures in photosensitive epilepsy."
Scientists measured the repetitive patterns of brain activity triggered when a person views certain images.
Ms Hermes said the UMC review, published in the journal Current Biology, has led to new research being planned in the area.
