Las Pautas de Accesibilidad del Contenido Web, Web Content Accessibility Guidelines (WCAG) 2.1, tiene tres criterios de éxito sobre el contraste mínimo de los elementos de una página web:
Sin embargo, no dice nada de lo contrario, el contraste máximo. Pero ¿pueden existir personas que tenga problemas cuando el contraste sea excesivo?
Sí, hay personas que pueden tener problemas.
En Accessibility and me: Marian Foley podemos leer:
I've been partially sighted since I was 9, and need large text and low contrast colours to be able to work. My requirements are quite unusual for someone with sight loss, as most visually impaired users need high contrast colours. My retinas can't process colour contrast properly, and spending more than a couple of minutes looking at high contrast material (web pages, documents, anything with regular stripes, spots or checks) gives me a splitting headache and motion sickness.
Y en este mensaje de Twitter:
Does anyone who works in accessibility for @Microsoft or @Apple follow me? I'd like to discuss settings needed for those with Irlen Syndrome. To us, text wobbles like an optical illusion. Luckily, it can be fixed with low-contrast color overlays, but that feature doesn't exist.
Según la Wikipedia, el síndrome de Irlen es:
Irlen syndrome, occasionally referred to as scotopic sensitivity syndrome (SSS) or Meares-Irlen syndrome, very rarely as asfedia, and recently also as visual stress, is a proposed disorder of vision.