The foundation posted its own warning: “For those who have been diagnosed with photosensitive epilepsy — or are simply sensitive to flashing lights — and are planning to watch the movie, they should be advised that the flashing lights may trigger seizures in some people.”

Certain frequencies of light can trigger seizures for photosensitive epileptics, about 3 percent of those with epilepsy. It is more common in children and adolescents, especially those with generalized epilepsy and a type known as juvenile myoclonic epilepsy, according to the foundation.

“There are certain things that send an input into the brain that gets a little excitable,” said Dr. Jacqueline French, the chief scientific officer of the foundation. “And that input triggers a seizure.”

To do so, the flashing lights have to occur at specific frequencies, the most common being between 10 flashes per second to about 25 to 30 flashes per second. The light also has to take up a lot of the person’s visual field — a little light in the distance isn’t going to be a problem, Dr. French added. The light triggers seizures that commonly last around 30 seconds, but people could take up to a week to feel better.

Ms. Aker, the foundation spokeswoman, said she was not aware of any other recent films or video games with triggers to photosensitive epileptics. Most recently, the foundation worked with Apple to remove a scene in a promotional video with flashing lights that caused symptoms in several photosensitive epileptics.

In 2016, the journalist Kurt Eichenwald, who had been critical of President Trump during the campaign, was sent a message via Twitter that said “You deserve a seizure for your posts” and contained a blinding strobe light. Mr. Eichenwald, who has epilepsy and had written about it, immediately suffered a seizure. A Maryland man was arrested in the case.