United States Department of Veterans Affairs
VHA Office of Health Information

Training for Testing HTML for 508 Compliance

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Testing for §1194.22 (j): Flicker Rate

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This module will focus on the flicker rate of objects on the screen.

The Section 508 requirement covering this is: §1194.22 (j) Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.

Why is this provision necessary?

  • Some individuals with photosensitive epilepsy can have a seizure triggered by displays that flicker, flash or blink.
  • The 2 Hz limit was chosen to be consistent with proposed revisions to the ADA Accessibility Guidelines.

Related Checkpoints

Remember, both testers and developers can use the checkpoints for this requirement to be sure the products they are working with will be accessible to users of Assistive Technology (AT).

Use the link above to look at the checkpoints now. You may wish to keep the window open as a reference to use as you complete this module.

Video Overview of this Requirement

To view a short video with additional information which may be helpful to testers and developers, select the video link below. The video will open in a new window; if you are using a screen reader to take this training, press enter when you hear, "To start, press Play button."

Flicker Rate Video in new window

Select Next to begin.

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