Visual accessibility isn’t limited to just the blind. Those with low vision or color blindness can also have issues when it comes to using websites. Navigation may disappear if the user makes the font large enough to read or vital diagrams might appear muddled and ambiguous if he can’t tell certain colors apart.
For the purposes of this book, a user with low vision is classified as anyone who must adjust the settings for the monitor to use a computer but is not using a screen reader. They might use a screen magnifier, or they might adjust the font size for a website. They also might override a site’s default fonts and colors in favor of ones that are higher contrast. These users might be people who are losing their vision, or they might be people who simply forgot their reading glasses.
Those that have low vision will often have issues with the following:
Sites that lose functionality or content when the font size is changed
Colors that don’t contrast highly enough
Sites where default styles can’t be overridden
Text in images
With modern browsers, one of the most common ways to make a website easier to read is to increase the font size. With proper CSS, this should cause the entire site to grow as well, including layout, images, embedded objects, and navigation. Though certain images may look best at certain dimensions, they might be impossible for a user to see, which would defeat the purpose ...