In plain English
This is the one accessibility rule that is about physical safety, not just usability. Rapid flashing, more than three flashes a second, can trigger seizures in people with photosensitive epilepsy. The rule is simple and strict: nothing on your page should flash faster than that (unless the flashing area is very small and dim).
Most stores never hit this, but any bold animated banner, strobing GIF, or flashy video is worth a quick check.
Who this is for
- People with photosensitive epilepsy, for whom flashing can cause a seizure.
- People with vestibular conditions, who are also affected by intense motion.
How to check and fix it yourself
Look at any animated or video content with rapid, bright changes. If anything flashes more than three times per second, slow it down, remove the strobe, or shrink and dim it below the threshold.
Bad: a strobing GIF banner or a video with rapid bright flashes.
Good: smooth animation with no rapid flashing; any flash under 3/second.If you are unsure, free tools like PEAT (the Photosensitive Epilepsy Analysis Tool) can test a clip.
Where we can help
This is rare but serious, so we scan any animated or video content on your store for flashing risk and flag anything that needs slowing or removing. It is a non-negotiable item on the common failures list.