At the same time, Disney dispatched a letter to exhibitors around the globe.

"Out of an abundance of caution, we recommend that you provide at your venue box office and online, and at other appropriate places where your customers will see it, a notice containing the following information: Star Wars: The Rise of Skywalker contains several sequences with imagery and sustained flashing lights that may affect those who are susceptible to photosensitive epilepsy or have other photosensitivities," Disney's letter stated.

For about 3 percent of people with epilepsy, exposure to flashing lights at certain intensities, or with certain visual patterns, can trigger seizures. This condition is known as photosensitive epilepsy. Flashing lights can also trigger migraines in those who are photosensitive.

Disney isn't giving details as to the sequences in question.

In summer 2018, Disney was criticized after concerns were raised on social media about strobe and flashing lights in Pixar's Incredibles 2, and their potential to trigger seizures or migraines. The Epilepsy Foundation posted an advisory during the film's opening weekend, and urged Disney to do the same (the studio subsequently did so).

This time out was different. "We thank Disney for reaching out to us and proactively providing information to movie theaters and moviegoers in advance of the movie's release," the Epilepsy Foundation said in Friday's post.

The sixth episode of HBO's Watchmen recently carried a similar warning: "This episode contains scenes with a strobing effect that could affect photosensitive viewers." And theme parks routinely have notices about flashing lights.

Star Wars: The Rise of Skywalker opens in North America on Dec. 20. It begins its international rollout several days earlier.

Here is the Epilepsy Foundation's statement in full.

The Walt Disney Studios and the Epilepsy Foundation are working together to advise photosensitive viewers to use caution when watching Star Wars: The Rise of Skywalker. The film contains several sequences with imagery and sustained flashing lights that may affect those with photosensitive epilepsy.

We thank Disney for reaching out to us and proactively providing information to movie theaters and moviegoers in advance of the movie's release. If you or someone you know are sensitive to lights, please consider the following as you make plans to watch the movie:

• Ask a friend to watch the movie first.

• Take your friend with you when you go see the film to alert you to which scenes contain the flashing lights so you block your eyes during those scenes.

• Teach your friend the three simple steps of seizure first aid — Stay, Safe, Side — so that they can assist if you have a seizure.

For about 3% of people with epilepsy, exposure to flashing lights at certain intensities or certain visual patterns can trigger seizures. This condition is known as photosensitive epilepsy and it's more common in children and adolescents.

To learn more about photosensitive epilepsy, including what you can do if flashing lights bother you, please visit www.epilepsy.com/photosensitivity.