Strobe lighting

Joel asked about the use of strobe lighting and any prohibition on this. I had a look into this and found the following:

Most people with photosensitive epilepsy do not have a problem with using modern computer screens, as they usually operate at a very high flicker frequency.  Computers with flatscreen monitors, such as laptops, have a liquid crystal display (also called LCD or TFT) that does not flicker. This makes them even less likely to trigger seizures. What is often more important than the type of screen is what is happening on the screen. For example, a flickering image or changing geometric pattern could trigger a seizure.

The organisation Ofcom regulates material shown on TV to avoid causing photosensitive seizures. Ofcom restricts the flash rate to 3 flashes or less per second, and restricts the area of screen allowed for flashing lights or alternating patterns.

Because of the size of the screen and the low intensity it is rare for seizures to be triggered by watching films in a cinema, or by hand-held miniature screens.

Interactive whiteboards, sometimes used in schools, have not been found to be a particular trigger for photosensitive epilepsy, although triggers can be individual.

A seizure can sometimes happen by chance while someone is watching TV or playing computer games or watching television, and may be a coincidence.  Tiredness brought on by watching the screen for a long time, or excitement when playing computer games, may also be a factor.

Can disco lights trigger photosensitivity?

Coloured lights do not usually cause a problem if they do not flash quickly.  However, deep red flashing lights, such as rear cycle lights, and strobe (flashing) lights can trigger seizures, especially if it is dark. If you know you are photosensitive, it may be best to avoid strobe lights, or cover one eye if you are suddenly exposed to them.

The Health and Safety Executive (HSE) recommends that strobe lighting in nightclubs or public performances is kept to a frequency of four hertz (flashes per second) or less.

SOURCE: http://www.epilepsysociety.org.uk/AboutEpilepsy/Whatisepilepsy/Triggers/Photosensitiveepilepsy 

There have been examples of bans based on this regulation:

The promo for Kylie’s upcoming single ‘Wow’ was due for a world premiere on Channel 4 on Wednesday night, but it was pulled after TV watchdogs found it broke guidelines.
Ofcom found the video’s use of strobe lighting effects meant the promo was unbroadcastable as it could prompt epileptic fits.
A spokesperson for Channel 4 says a revised video will be shown, but Kylie’s now lost her high profile slot.
“We are waiting for the new version to be ready. It will be show on Music Playlist,” they state.

SOURCE: http://www.entertainmentwise.com/news/40329/kylie-minogue-video-banned

On a similar note:

You might think there’d be a great many reasons to criticise a Westlife performance on The X Factor – schmaltz, insincerity and over-reliance on standing from a stool after a key change, for example.

However, Ofcom were more concerned about the physical effect the lasers employed by the show’s lighting department might have on light-senstive sufferers of epilepsy.

And it turns out their fears might’ve been worthwhile, as the light intensity of the lasers in that show turned out to be five times as intense as they’re legally allowed to be.

SOURCE: http://watchwithmothers.net/2010/01/26/newsgush-ofcom-criticises-x-factors-westlife-performance/#more-4941