The Epilepsy Foundation is warning fans of the Twilight Saga, "Breaking Dawn" that a scene from the film could pose a health threat.
The movie, No. 1 at the box office for a third straight week, has apparently caused seizures in moviegoers who have epilepsy.
At least nine people have reported having a seizure while watching the movie that includes a scene with intense flashing lights.
Evana Yates, a neurology nurse practitioner at Summit Medical Center, told Nashville's News 2 flashing lights often trigger seizures in epilepsy patients with photo sensitivities.
"What typically happens with the flashing lights is they center on the visual cortex," she explained, and that often it "can cause them to have cardiac arrest, where they stop breathing. Their heart can stop. "
Some of the moviegoers who've become sick did not know they have epilepsy.
Some severe seizures, triggered by certain sounds or flashing lights, can be deadly.
"It could be that they could die if treatment is not initiated, and if they're in the midst of an epileptic attack," Yates said.
The movie is popular with teenagers, some who have also become sick.
Yates said that could signal that the person may have epilepsy that has never been diagnosed.
Still, some of the Twilight fans may not be able to stay away from the film, which is showing on dozens of screens in the Nashville area.
For those fans, Yates has recommendations.
"First, make sure you've taken your medication. Sit as far away from the screen as you can," she said.
She suggests wearing sunglasses or watching the flashing lights while covering one eye could lessen the possibility of a seizure.
Regal Cinemas on Friday posted a warning outside box offices notifying people prone to photosensitive seizures of the flashing lights.
The Epilepsy Foundation also sent out a warning and is asking the movie company that produced "Breaking Dawn" include a warning on the screen before it's shown.
Click here to learn more about epilepsy and seizures.