Web animations in videos, GIFs, PNGs, SVGs, and JavaScript can create engaging user experiences. However, strobing or flashing elements create serious accessibility barriers, causing eye strain for many and potentially triggering seizures in people with photosensitive epilepsy.

Flashing content can be harmful even at low frequencies — some individuals experience symptoms at less than 3 Hz (flashes per second). Similarly, patterns with more than 5 light-dark stripe pairs can provoke seizures regardless of orientation. Color choices also matter significantly, with red flashing being particularly problematic for people with photosensitive seizure disorders.

If your design absolutely requires flashing content, never expose users to it without warning. Implement clear opt-in mechanisms with explicit warnings about potential risks.^[1] Better yet, consider alternative design approaches that achieve similar engagement without relying on potentially harmful visual effects.

Use specialized testing tools like the Photosensitive Epilepsy Analysis Tool (PEAT) or the Harding Test to evaluate animations before implementation.