ELI5, how can you tell if flashing in videos is severe enough to need an epilepsy warning?


Prompted to ask because some channels I watch on YouTube put warnings, and some don’t… But the “severity” of the flashing always seems very different in the channels that do put warnings.
I don’t currently have anyone in my life with epilepsy, but I definitely wish I understood what could be a problem for anyone I may meet in the future.

In: 6

It’s a “better safe than sorry” situation. Epilepsy can be triggered by a wide range of things, like this 2 second animation from Cyberpunk that had the be patched out: https://youtu.be/HjbknFsV_NU

Epilepsy warning, just in case.

I always thought to trigger an epilepsy attack you needed to have a several second long light flash you look into, just seeing this 2 second flicker being enough really opened my eyes to how sensitive people can be to this sort of thing.

So if you have rapidly flashing lights, you throw in a warning just in case. Better let people know who might be affected than have a bunch of epilepsy cases in your hand.

At least for broadcast television, there is a standard called the [Harding Test](https://en.wikipedia.org/wiki/Harding_test), which is done by proprietary software that determines if elements within a video could effect people with epilepsy. Broadcast networks & streaming services in the US and UK use this test for programming and commercials.

The software for the test is very expensive, but you can check your content via uploading to [their website](https://hardingtest.com/pricing) if you’re interesting in finding out if your content would pass.

Since it is so expensive, [here’s another helpful site](https://veroniiiica.com/2018/09/05/how-to-check-videos-for-flashing-light-sensitivities/) that includes some tips to help avoid common mistakes and when/where to include warnings for viewers.

To be fair, epileptic seizures can be triggered by anything. I have witnessed many seizures, sometimes they happen for no apparent reason, other times there is a trigger that is more apparent. They vary for each individual. Some people can ‘sense’ when they are coming, others cannot. Flashing lights are just a more well known trigger. It doesn’t work on every person with epilepsy however.