As reported by ‘The Hollywood Reporter,’ two men had seizures during the birthing scene in ‘Twilight: Breaking Dawn Part 1.’ A California man convulsed and had difficulty breathing, and a man in Salt Lake City had a similar seizure. Both men are fine.

The seizures happened during the film’s birthing scene because the alternating flashes of white, red, and black images trigged a photosensitive epileptic reaction. “It’s like a light going off because it hits your brain all at once,” Dr. Michael G. Chez told CBS Sacramento. “The trouble with theaters is that they’re so dark, the light flashing in there is more like a strobe light.”

Photosensitivity is when rhythmic flickering lights make someone uncomfortable, causing at worst a headache. According to the Canadian Epilepsy Alliance, flashing lights of high intensity pulsating in a pattern can trigger seizures in people with photosensitive epilepsy. Not all types of flashing lights will cause seizures, but sometimes nerves can be overstimulated by rhythmic lights when the pattern is focused to the central area of vision and seen by both eyes. According to neurologist Jerome Engel, “Instead of [the nerve cells] firing individually, like fingers playing notes on the piano, many fire at once—like the banging of dissonant chords.”

The birthing scene is a series of close-ups, and in a dark theater, I can understand how the sequence could trigger a seizure for those with photosensitive epilepsy based upon what’s been explained. If you have photosensitive epilepsy and want to see the film, cover or advert your eyes when Bella goes into labor in the living room. You can watch again once the baby is born. The scene is not long, and you will not miss any vital visual moments. The sounds are strong and provide the information needed to understand the scene.

This is not the first time a film has caused visual discomfort. ‘Speed Racer’ and some 3D films have caused headaches in many moviegoers. Since there is no one specific rhythmic flashing light pattern that causes a photosensitive epileptic seizure, the  filmmakers should not be accused of any malicious intent.