Flashing ads on websites trigger seizures?

On another web-based message board I visit, which puts banner ads on every page, people like to complain about the flashing ads by saying that somebody they know had an epilectic seizure upon viewing one. This smacks of urban legend to me – if not a bald-faced lie. Does anybody know if there’s any truth to it?

Well, it is true that some folks can have seizures triggered by rapidly flashing lights or colors, and it’s likewise true that there was an episode of Pokemon that caused this effect in a large number of children when it was aired in Japan. It’s conceivable that a web banner could do the same thing, but since it’s such a small portion of the field of view (rather than the full screen), it’d have to be less likely. Has it ever actually happened? I don’t know.

My younger brother has a seizure disorder - nearly all of his seizures have occured when he was using a computer or watching television, and when he comes out of it the last thing he remembers is seeing a flashing light on the screen. So I’d guess it is true. Can anyone explain the science behind this?

It’s possible. My sister has epilepsy and in the 1980s, she complained of seizures when using the old monitors (with their poor resolution and slow refresh rate). But now of course she uses an SVGA monitor and has no trouble with seizures while using it. She also suspects fluorescent lights with their flickering can trigger seizures, but she isn’t as sure about that.

The National Society for Epilepsy (in the UK) says that a frequency of 5 or more flashes per second could cause a seizure among a very small number of epileptics. I find it hard to believe that the ads I’ve seen are flashing that fast, but that’s just an impression.


Do you remember *THE ANDROMEDA STRAIN *?
Wasn’t it Kate Reid who had a seizure and failed to identify a culture due to a blinking light?

I remember that book, but I think it was a male character who had epilepsy.

I’ve seen some really obnoxious ones that flash extremely fast. (Anyone seen the “Winner!” one?)

All video games now carry a warning (typically in he instruction manual) stating that a certain segment of the population experiences epileptic seizures due to flashing lights (known as photosensitive epilepsy) and that if this applies to you, don’t play the game. Typically the flashing has to be pretty bad to cause a seizure (the Pokemon episode with the color-cycling background, Jurrasic Park the Arcade Game, strobe lights, etc…) but I guess it is possible with an isolated banner ad. If you’re viewing at a low resolution (so the ad takes up a lot of space onscreen) and you’ve got the lights off, that’ll probably exacerbate it.

I haven’t seen testimony from anyone that its actually happened to, but have seen a lot of people complaining about specific ads that it could happen with.

It was the female character with the epilepsy. She was shown viewing images of the cultures with a blinking red warning light in her field of vision. The image of interest passed by while she was in a “trance”.

Don’t know if the name is right. I remember her character looking to be in her late 40s.

I was trying follow up on friedo’s comment (man or woman in AS) and ran into this web page. Gives a time line of the flashing effect and seizures ack to the early 1800’s.


I remember that. It’s in the movie and the book, although I believe that the character is a man in the book.

In the movie, she has a bad seizure after looking at a flashing alarm light and brief one after looking at the flashing colon in a digital clock.

In the book it describes the clock episode from the guy’s point of view. He just put on his clothes (fresh, new, and cool) and he glances at the clock and the clothes get warm in about a second. He muses something about new fabric, looks back at the clock and realizes that he’s been sitting there for 10-15 minutes.

Also, I believe that in the book it specifies that it’s red lights that cause it. I remember him avoiding looking at the red flashing lights on the police car that picks him up and takes him to Wildfire (or wherever).

Most browsers allow turning off graphics, so that should work for anyone susceptible to this, unless it’s possible to force the ads by ignoring the settings (I don’t know).

Remember when the Simpsons went to Japan & Bart started watching a cartoon & immediately passed out due to the flashing image?

A flashing, eye catching light pulsating at a certain amount of cycles per second can trigger seizures. There is/was an annoying website that one could stumble on that consisted of a rapidly flashing screen of red light with some design in the background. Once there you got locked in and had to reset to escape. In my opinion, that site, set up as a ‘joke’ {why are computer jokes such a pain in the a++?} was designed to trigger seizures.