23,000 people in the UK suffer from photosensitivity.
(This means that flashes, strobe lights and flickering images, typically at rates of 16 to 25 times a second but as low as three and as high as 60, can trigger an epileptic fit. A Pot Noodle advert in 1993 sparked three reports of seizures and prompted concern and a ban on the advert. But in Japan in 1997 more than 600 children were admitted to hospital after suffering epileptic seizures after watching a Pokemon cartoon. More recently in the UK 18 people reported ill effects after watching an animation to launch the London 2012 Olympics.)