Seizures induced by extended periods of bright, flickering light, known as photosensitive epilepsy, is a genetic condition. It usually shows up in childhood, sometimes during the teenage years. And sometimes it lies dormant well into midlife until the perfect storm of flashing lights, quick cuts and intense, visceral drama unlocks it, like the birth scene in Twilight: Breaking Dawn has been doing recently for unsuspecting audience members.

Since the film’s opening a little more than a week ago, a handful of people have reported experiencing convulsions, blackouts and shortness of breath all during that gruesome scene. There’s even a Facebook page where seizure sufferers can share their experiences.

Remember the Pokemon incident in 1997, when some 600 Japanese children were rushed to the emergency room? Only about two dozen of them had actual seizures, but the incident sparked an ongoing debate between parents, doctors and the anime and video game industries. There are also a few similarities between the photosensitive seizure-triggering sequence from that animated TV show and the one in this live-action film (not least of which is the devoted, almost feverish fan base, ensuring more than the usual amount of eyeballs). The Pokemon sequence featured intense flashes of red and blue lights (about 12 per second), followed by an extended stretch in which Pikachu’s eyes pulsed white flashes continuously for five seconds. After the incident, Japanese health and broadcast officials collaborated on guidelines for content creators that specifically cautioned against the use of flashing red, limiting flickers to three times per second. They also cautioned that if featured at all, a flickering sequence should last no longer than two seconds.

The Breaking Dawn birth scene combines the two—flashes of red (and black) and flashes of white light—into one extended and bloody scene. Delivering a child is terrifying however you look at it, and the stylistic choice to cut that action in Breaking Dawn with intertwined flashes of the horror genre’s three iconic colors (harsh white, blood red and deathly black) no doubt heightens an already gripping moment. But red flashes, in particular, have long been documented as the chief triggers to these kinds of seizures by the medical community. Were the filmmakers aware of this?

Those vulnerable to the effects of flashing light are more at risk the closer they are to the screen and the larger that screen is. Intensity is also key. Jessica Solodar, writing on her blog about the connection between video games and photosensitive seizures, notes that when occurring at a particularly dramatic and physically intense point in a film or game, flashing lights and quick cuts are more likely to trigger an epileptic response. “Stress lowers the seizure threshold, meaning that the same degree of flashing in a context that’s not so tense might not result in a seizure,” she says.

In a similar way, the stress of watching the horrific amputation scene in 127 Hours induced dozens to faint in their seats.

So who is responsible for these unintended effects? As Will Oremus suggested yesterday in Slate, shouldn’t someone—the studio, the producer, a ratings board—be held accountable?

In the United Kingdom the filmmakers and distributors are responsible for identifying “any material that could provoke seizures and other adverse reactions in audiences.” Did the British Board of Film Classification and the U.S.’s much looser Motion Picture Association of America, which often turns a blind eye to gruesome violence, fall down on the job? The BBFC did, apparently, slap a warning in the U.K. on Gaspar Noe’s Enter the Void, which also included several extended sequences of flashing and flickering lights. Those who could stomach the flashes and the violence found Noe’s visual experiment rewarding. Others just covered their eyes.

Filmmakers and software makers take great care during stereo 3D production and post to precisely calibrate and fix the interocular between cameras. It’s essential to the stereo film’s success that viewers can watch the end result without getting disoriented or nauseous. One wonders why the same logic doesn’t apply to the quick-cut strobe effect, though it likely has something to do with the differences between mere technical requirements and that highly subjective term, “technique.”

Slate‘s Oremus says some experts have already cautioned that brighter digital projectors in larger multiplexes could make these kinds of seizures much more common. Maybe the projectors themselves should come with a warning—but then that would just be shooting the messenger.

As the photosensitive problem widens from video game and anime to feature films, someone, or some organization, here in the U.S. needs in the very least to devise a system of guidelines and warnings. According to a post today on the Breaking Dawn Seizure Facebook page, Summit Entertainment’s PR team says it is still considering the evidence before the studio makes an official statement.

Do you as filmmakers, especially the editors, feel you have a responsibility to keep your cuts from becoming completely toxic for the portion of the audience possibly at risk?