Playing computer games very rarely triggers epileptic seizures in people without a known history of epilepsy. Those people who do have a seizure for the first time when playing video games usually have an unrecognised susceptibility to seizures triggered by flashing light, that is, most of them are photosensitive. It is important to realise that epilepsy is common and that one should not be surprised that seizures will sometimes occur by chance whilst someone is playing an electronic game or watching TV, without any causal link. Proper investigation is required to determine the true cause of a presenting seizure in order to give appropriate medical advice. Ordinary coloured lights do not usually cause a problem if they do not flash, however, stroboscopic lights can trigger seizures, particularly if the background illumination is low and there may be other environmental triggers e.g. stress, excitement, tiredness etc.
Some local authorities do have rules concerning the flash frequency of strobe lighting.
The local Environmental Health Department will be able to give you more information on this. Unfortunately, if a person is known to be photosensitive it may be best to avoid stroboscopic lights. Change channels on the TV using a remote control to avoid going too close to the screen. It is rare for seizures to be triggered by film in a cinema or hand held miniature screens. Excess tiredness may increase the risk of photosensitive seizures.