WCAG 2.3–Seizures and Physical Reactions

Do not design content in a way that is known to cause seizures or other physical reactions.

This is a mandatory Level A requirement under WCAG 2.1 – all UAMS websites must comply by April 26, 2027 (DOJ Title II ADA final rule for state and local government entities).

Success Criterion 2.3.1 Three Flashes or Below Threshold (Level A – Required)

Web pages must not contain anything that flashes more than three times in any one-second period, or the flash must be below the general flash and red flash thresholds.

People with photosensitive epilepsy can have seizures triggered by flashing or flickering content (especially red flashing). These thresholds are based on international broadcasting standards adapted for computer screens.

As a UAMS CMS Editor – What You Must Do

• Never upload or embed content (videos, GIFs, animations, sliders, etc.) that flashes more than 3 times per second.
• Avoid auto-playing animated GIFs or videos with strobe effects.
• If content flashes, limit it to a very small area of the screen (less than 25% of a 10-degree visual field – roughly 341 × 256 pixels on a 1024 × 768 screen).
• Blackboard Ally for Websites will flag flashing content automatically – fix any issues immediately.

Failure to meet 2.3.1 prevents the entire page from being conformant to WCAG 2.1 Level AA.

Success Criterion 2.3.2 Three Flashes (Level AAA – Recommended but Not Required)

Web pages must not contain anything that flashes more than three times in any one-second period, regardless of size or brightness.

This is stricter than 2.3.1 and eliminates nearly all risk, even from tiny flashing pixels (which can become larger when users zoom or increase contrast).

While not required for UAMS’s 2026 compliance, we strongly recommend meeting it for patient-facing or public-safety content.

How We Test at UAMS (2025–2026)

• Blackboard Ally for Websites performs automated scanning for flashing content on every page.
• Manual review during editing (preview the page with “Reduced Motion” enabled in your OS/browser settings).
• For videos: upload to YouTube/Vimeo first (their built-in tools flag flashing risks), then review Ally feedback after embedding.