If you or someone you love is epileptic or has issues with rapidly flashing lights, Apple has added a new feature to try and protect you.

In case you’re unaware, epileptic people have been attacked past and present by people sending videos and gifs of rapidly flashing lights, which can cause epileptics to have seizures. Many sites have attempted to erect warnings and protections for these people. Apple is now getting on board with device-wide features in iOS/iPad OS 16.4 and Ventura 13.3.

I should say that I am not an epileptic, nor am I sensitive to flashing lights, so my opinions on its effectiveness are colored by that. I also should say these protections are not perfect and cannot substitute vigilance. In my testing I found the Mac to be fairly aggressive at dimming the screen. The iPhone, however, was a little hit-or-miss with videos from the YouTube web page being detected and dimmed but the exact same videos played in the app not being dimmed in the YouTube app. And these were not simply random YouTube videos, but ones specifically containing rapidly flashing lights and that started with epileptic warnings. Meanwhile apps like Twitter, Facebook Messenger, and browsers seemed fine. I think this is a good feature to turn on if you are concerned about this, but sadly it cannot substitute for vigilance at this time.

With that said, here’s how to enable it on your Apple devices.

Mac

Open the Settings app. Scroll down on the left side bar and click on the Accessibility section. Then, in the right sidebar, look for and click the “Display” button. Once it opens, look for “Dim flashing lights”, which should be the fourth option from the top. Click the enable switch so it turns blue and enables. Now you should notice the screen dim separate from its light-sensing and manual control dimming features if the colors rapidly change on screen.

iPhone & iPad

Doing this on the iPhone and iPad is similar to doing it on Ventura, but in a slightly different section. Open the Settings app. Scroll down and click on the Accessibility section. Then look for “Motion” and tap that (not my first guess either). Third from the top should be “Dim flashing lights”. Tap the switch next it so it turns green and enables. Now you should notice the screen dim separate from its light-sensing and manual control dimming features if the colors rapidly change on screen. As I mentioned before, it seems more responsive in some apps than others. Hopefully with future updates this will continue to improved.