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Flashing images or rapidly changing patterns – although they attract users’ attention, they pose a serious threat to people suffering from photosensitive epilepsy. Website owners are often unaware that inappropriate graphic elements can trigger a seizure in light-sensitive users. That is why it is so important to adapt websites to accessibility standards. WCAG (Web Content Accessibility Guidelines). In this article, we suggest which elements of a website should be taken into account in the context of people with epilepsy.
What is photosensitive epilepsy?
Photogenic epilepsy is a type of epilepsy in which seizures are triggered by light or visual stimuli. The degree of sensitivity to light varies from person to person – some people experience seizures even with minimal exposure, while others only experience them in specific circumstances.
Photogenic epilepsy – symptoms
When a light-sensitive person encounters an irritating element on a website, they may experience an epileptic seizure, usually lasting several minutes. Therefore, it is worth paying attention to what content may exacerbate the symptoms of the disease and eliminating it.
What content on the website could cause an attack?
Elements that are bright, dynamic, change rapidly or present intense contrasts are among the most common triggers of photogenic epileptic seizures.j. First and foremost, these are:
Moving or flashing elements
Flashing banners, dynamic animations or rapidly changing advertisements. Flashing at a frequency of 3 to 50 Hz is particularly dangerous. WCAG recommends limiting moving elements and avoiding flashing at a frequency of more than three flashes per second.
Automatically played videos
Videos that start playing without the user’s consent, especially those with intense lighting effects or rapidly changing scenes, are a potential hazard. WCAG requires that users be given control over such content – it should be easy to pause or turn off.
Contrasting patterns
Pages with backgrounds or elements featuring bold, contrasting patterns that may attract attention also pose a risk. Using more balanced graphic designs reduces this risk.
Animation triggered by interaction
This refers to all kinds of animations that appear as a result of user actions, e.g. moving the cursor to a specific place. Unless such interactions are necessary for the website to function, they should be disabled.
Photogenic epilepsy – regulations in Poland
Issues concerning the accessibility of websites and mobile applications for people suffering from photosensitive epilepsy is regulated by the international WCAG standard. The guidelines contained therein apply in Poland. The Digital Accessibility Act of 4 April 2019. The document applies to government offices, local government units, institutions and other public entities.
In addition, the WCAG guidelines are part of the Polish Accessibility Act, which requires certain companies to comply with them. Therefore, entrepreneurs should adapt their websites – accessible products and services are gradually becoming a legal obligation.
Website monitoring tool
Ensuring website accessibility is an ongoing process. It is worth using not only one-off audits, but also monitoring tools. Such programmes analyse the website on an ongoing basis for compliance with WCAG and detect elements that are potentially dangerous for light-sensitive people. An example of such a tool is the SAT platform.
When managing a website, it is worth remembering people with photosensitive epilepsy by creating content that does not flash or flicker, or by warning about such materials (while blocking their automatic playback).
