Photosensitivity is defined by a pattern of occipital or more diffuse spikes and waves. Several techniques are needed for exploration: intermittent light stimulation (ILS), patterns, TV-screen, video games. Photosensitivity is a genetic characteristic. Only diffuse spikes and waves induced by ILS are correlated with epilepsy. Pure photogenic epilepsy is characterized by seizures induced by visual stimuli alone, usually by TV-screen. Video games may also have a triggering effect due to the slow-moving patterns or intense brightness. Several epileptic syndromes are associated with photosensitivity with or without visually-induced seizures. These syndromes are most often generalized and idiopathic.