Safe to play a game that passes the seizure test?

I've been using charts like this one to show results of testing for adherence to photosensitive epilepsy guidelines.

Until now I’ve posted charts in this format to show whether a game meets photosensitive epilepsy guidelines…

According to a Reddit post, a game that I’ve said “passed the seizure test” triggered a seizure. Recently the same game—Hearthstone—could have been implicated in a professional gamer’s seizure that happened during a live stream. What’s going on?

I write about games I’ve tested to alert readers to the games that don’t meet internationally recognized image safety guidelines. But I don’t want to create undeserved confidence that a game that passed the seizure test will be safe for anyone with photosensitive epilepsy.

Ian Hamilton, a user interface designer who specializes in and advocates for game accessibility, clarifies the role of testing this way:

“Passing the Harding test doesn’t mean that a game is safe. It means ‘reasonably safe’ because common triggers have been avoided. Something that gets a ‘pass’ can still absolutely cause seizures.”

I regularly write that your experience may differ, that I’m not trained in quality assurance, that I test excerpts of game play, and that health and lifestyle variables affect every individual’s vulnerability to seizures at any given time. Still, the meaning of my findings could be misleading without an understanding of the limitations of the seizure test itself:

  1. the pass/fail guidelines aren’t expected to prevent seizures in all individuals
  2. the test was designed for TV images, not video games

What the Pass/Fail guidelines mean

The guidelines originated in 1994, when the UK’s agency for regulating TV broadcasting (now known as Ofcom) inserted into its code of standards some technical guidelines to accommodate viewers with photosensitive epilepsy. These guidelines, based on studies of photosensitive epilepsy and consultation with Prof. Graham Harding and other photosensitive epilepsy experts, detail flash rates and spatial patterns that typically trigger seizures in people with photosensitive epilepsy. Specifications regarding saturated red images were added later, after the 1997 Pokémon incident in Japan.

Some compromises in the guidelines were made for the sake of practicality. Criteria for acceptable images (commonly referred to as the Harding test) were developed with the understanding that they would realistically protect most individuals with photosensitive epilepsy, but not all. For example, the guidelines permit images that flash at a rate of up to 3 times per second because flash at that frequency affects only 3 percent of photosensitive individuals. UK regulators decided that was “an acceptably small risk.”

I'm taking the word "safety" out of the chart since passing the test doesn't guarantee seizure safety

…but I’m updating all the charts by removing the word “safety” since passing the test doesn’t guarantee seizure safety.

The introduction to the guidelines states that their purpose is “reducing the risk of exposure to potentially harmful stimuli.” It also concedes that even when broadcasting images that comply with the guidelines,

“it is…impossible to eliminate the risk of television causing convulsions in viewers with photosensitive epilepsy.”

Applying TV guidelines to video games

There are no formal guidelines for reducing the seizure risk from video games. A 2005 consensus paper by experts on photosensitive seizures acknowledges that additional work would be required first on the existing guidelines for TV. In the meantime, it is reasonable to use the television guidelines since the impact of screen images on the visual system is the same.

The biggest challenge in applying TV specifications to video games is explained in the consensus paper:

“These principles are easier to apply in the case of fixed media (for example, a prerecorded TV show), which can be analyzed frame-by-frame. Interactive media, such as video games, may afford essentially limitless pathways through the game, depending on user actions. Therefore …in the case of video games, the consensus recommendations apply to typical pathways of play but cannot cover every eventuality of play.”**
Also,when players set their own viewing perspectives and preferences in newer video games, they may create unanticipated seizure risks.

Reducing risk going forward

In sum, a game that fails the Harding test is best avoided by those with photosensitive epilepsy. A game that passes is less likely to act as a trigger. Despite all the qualifiers, I believe there’s value in reminding people that seizures can happen to anybody, that certain video games can trigger them, and that you can lessen the risk by selecting games without lots of flash and patterns. Other strategies to lessen the risk of photosensitive seizures can be found here and here.

Tip of the hat to Ian, who suggested that I avoid the word “safe” when describing games that have passed the test. I also will be revising my prior posts to do some rewording.

Gamer’s seizure on live stream

Here’s a reminder that seizures can happen to anyone. A professional gamer known as Lothar had a seizure recently during his live feed while playing Hearthstone on Twitch. Lothar apparently has no history of seizures and the seizure may or may not have any connection to Hearthstone. In updates about his condition and hospital stay, Lothar didn’t mention photosensitive epilepsy nor has he said he’s been advised to limit his gameplay. 

For the record, Lothar is also a body builder—he’s obviously a guy who has enjoyed good health and takes good care of himself. Lothar has a large and caring following and has been receiving lots of well wishes as he recovers. Why do I mention this incident here? Viewing the incident (you can find it on YouTube) and seeing how it affected so many fans who care about him reinforced for me the seriousness of seizures and the importance of preventing those that are preventable.

** Graham Harding et al. (2005), Photic- and Pattern-induced Seizures: Expert Consensus of the Epilepsy Foundation of America Working Group. Epilepsia, 46: 1423–1425.

4 Comments on “Safe to play a game that passes the seizure test?”

  1. Kathy says:

    What type of lenses do I need to purchase

  2. Norman says:

    Of course, wearing lenses (either non prescription or prescription) to subdue the effects of the flashing and red triggering wavelength of light may help or even eliminate the problem while playing. While testing the games provides excellent ratings protection guide, lenses that eliminate the problem can resolve any rating.

  3. tabatha says:

    My son has recently been diagnosed with these flashing light seizures. It was not a video game that triggered it and he has not been restricted from playing video games as of yet, just told to be careful with them. But they all have the same warning on them so not sure how to know which ones are a problem for him. He has some on his Christmas wish list and i know I cant put him in a bubble like I want to but I’m worried I’m handing him a ticking time bomb with them if I get them. I know you cant garauntee anything but have these PS4 games been tested for seizure triggers.?.?.?

    Ark survival
    Battlefield 1
    Horizon Zero Dawn

    Also The Star Wars Battlefront i see on your list of fails. he has played this many many many times with seemingly no issues. Is it different for each individual or is he getting lucky and I should take this from him?

    Is there something within the game settings or tv setting we can do to at least lessen the odds of one occurring?

    Thanks so much for your time. This is all new to me and I’m trying to learn.

    • jsolodar says:

      It’s a real problem that you can’t tell from the packaging which games are in fact most likely to be risky for people sensitive to flash. The warnings protect the developers/marketers from liability but don’t give consumers much meaningful information.

      There is no industry organization that tests these games (and releases the results), as least as far as I know. There are forums for most of these games where players sometimes discuss specific features that cause problems for them, including things that flash. Sometimes in the discussion people with respond with suggestions for specific settings in the game that they wish they could select as a way of getting around problem spots.

      And it’s really impossible, unfortunately, to know for sure whether a specific game will trigger a seizure in a specific person–although there are some sequences that are so over the top that many people with visual sensitivity are likely to get triggered. There are no absolutes…the same visual sequence could be fine one day, but on another day a seizure could be triggered if the same individual is ill, sleep-deprived, highly stressed, or under the influence.

      In general, smaller screens/greater distance from the screen is safer. If the screen takes up a good portion of the visual field, the effects are stronger. If there are contrast and brightness settings on a monitor/TV, it’s safer to turn those down to minimize the effects of flash. If you can get him to wear dark blue glasses while playing, those are very protective for most people with photosensitive epilepsy.

      The testing I do is based on gameplay clips and official trailers–I am not set up to test all possible visual sequences. So there’s a certain amount of randomness to all of this. Your son may not have come across a game sequence I tested that failed. Sometimes there are a couple of seconds of problem graphics in half an hour’s worth of gameplay, and I decide to list the game as “fail” because if there’s at least one failure in there, there could be more. It’s maddening, isn’t it? A lot of trial and error, unless someone is extremely sensitive and you have to set down some rules.

      That said, I did test Battlefield 1 last year and it failed. The last time I tested Horizon Zero Dawn, 2.5 years ago, it passed. I am testing some other games this month and will try to look at the ones you listed.


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