“Spider-Man: Into the Spider-Verse” is an animated take on a world with multiple Spider-Men where teen Miles Morales learns how to become Spider-Man and fight a villain. The movie premiered Friday and is already topping the box office, but some viewers are warning others about the flashing lights throughout the movie.

Moviegoers are using social media to spread awareness that the film uses flashing, or strobe, lights, especially at the beginning of the movie. Strobe lights, which flash at a rapid speed, can trigger harmful and dangerous reactions for people with epilepsy, migraines or other chronic illnesses. Intense visual stimulation can also cause issues for people with sensory processing disorders or those on the autism spectrum.

another reminder about the epilepsy warning for #IntoSpiderVerse RT for those who may not know pic.twitter.com/NxdO8UV9w6 — ‎ ‎⎊ resound ⎊ ????⚪️????⚫️ (@Moosephu) December 15, 2018

Some moviegoers said there weren’t any warnings at the theaters about the lights while others said there were posted signs at the theater. The Mighty has reached out to Sony to clarify. This isn’t the first animated film in 2018 to cause concern for people with chronic illnesses. In June, viewers warned others about the strobe lights in “Incredibles 2,” and Disney required movie theaters to post flashing light warnings in response to the public outcry.

Films that rely on strobe lights usually undergo a Harding test. This test checks how safe the movie is for those with photosensitive seizures, but it does not set safety parameters for others who may experience issues from the lights because of another chronic illness.

“Spider-Man: Into the Spider-Verse” employs flashing lights, bursts of bright colors and a “glitchy” feature that blurs the image. If you’re interested in seeing the movie but are worried about the effects, you can view the trailer to give you a better idea of what to expect during the movie. You can also wait to see the movie after it’s released on DVD. The epilepsy foundation suggests watching TV in a well-lit room and sitting further back from the screen to reduce the chance of experiencing any side effects.