People With Low Vision
Far more people have low vision than are blind. Most of them are not using a screen reader — they are using your page at 300% zoom.
Low vision is not blindness with extra steps. It's your site at 400%.
At 400% zoom on a laptop, the visible viewport is roughly the width of a phone. A layout that was designed for a wide screen and never tested narrow starts scrolling in two directions at once, which means reading one sentence requires scrolling right and then back left for the next line. Magnifier users see a small window moving across a large page, so anything that depends on noticing something far from where they are looking — a toast in the corner, an error at the top of a long form — is invisible to them.
Scale: Low vision is substantially more common than blindness; the World Health Organization estimates at least 2.2 billion people worldwide have a near or distance vision impairment. (Source: WHO. Survey-based disability figures undercount — treat this as a floor.)
What they're using
- Browser zoom, often 200% to 400%
- Screen magnifiers like ZoomText or the operating system's built-in magnifier
- High-contrast and inverted color modes at the OS level
- Custom stylesheets and reader modes that override your typography
6 barriers we find most often, and the criteria behind them.
Layouts that do not reflow
Fixed-width containers, wide tables, and absolutely positioned elements force horizontal scrolling when the effective viewport narrows. WCAG draws the line at 320 CSS pixels wide — the equivalent of 400% zoom on a 1280px screen — with no two-dimensional scrolling.
Success criteria: 1.4.10 Reflow AA
Text that cannot grow
Type sized in fixed units inside fixed-height containers either refuses to scale or scales and gets clipped. Text must be resizable to 200% without loss of content or function.
Success criteria: 1.4.4 Resize Text AA
Low contrast styled as sophistication
Light gray on white, brand color on a tinted background, placeholder text as a label. Body text needs 4.5:1 against its background; large text needs 3:1. The most common failure on a professionally designed site is the one the designer liked best.
Success criteria: 1.4.3 Contrast (Minimum) AA
Interface components and graphics below 3:1
Input borders, focus rings, toggle states, icon buttons, and the meaningful parts of charts all need 3:1 contrast. A form field whose only boundary is a faint line is a field some users cannot find.
Success criteria: 1.4.11 Non-text Contrast AA
Text baked into images
A price list, a schedule, or a quote rendered as a JPEG blurs into unreadable pixels the moment it is magnified, and cannot be restyled or recolored.
Success criteria: 1.4.5 Images of Text AA
Spacing overrides that break the layout
Users who increase line height, letter spacing, or word spacing to read more comfortably should not lose content. Fixed-height containers clip text the moment it is given room to breathe.
Success criteria: 1.4.12 Text Spacing AA
The changes that actually remove the barrier.
Test at 320 pixels wide, not on a phone
Set the browser to 1280px and zoom to 400%, or set the viewport to 320px. Then scroll the page. If anything moves sideways, that is the failure.
Check contrast against the actual rendered background
Not the hex in the design file — gradients, overlays, and images behind text all change the real ratio. Our free checker samples what the browser actually painted.
Let containers grow
Min-height rather than height, no overflow:hidden on text containers, and relative units for type.
Put errors and confirmations near the thing they describe
A magnifier user looking at field 9 will never see a message rendered at the top of the page.
Three tests you can run before you call anyone.
- Zoom to 400% and complete one transaction. Note every time you have to scroll horizontally.
- Apply the WCAG 1.4.12 text-spacing overrides in the browser console and look for clipped text.
- Run /accessibility/checker/ on your own page — contrast is one of the things it evaluates against real rendered pixels.
If any of those go badly, you have your answer and you did not need a vendor to get it. What a vendor is for is the part after: knowing which of the 55 criteria that maps to, how deep it goes, and what it costs to fix properly rather than patch.
Run the Free CheckerWhere this shows up in practice
Other people the standard was written for.
People With Color Vision Deficiency
Color can carry meaning — it just cannot be the only thing carrying it. This is the cheapest WCAG failure to fix and one of the most common.
Read the profileDeaf and Hard of Hearing Users
Every piece of information you deliver by sound needs an equivalent in text. Auto-captions are a starting point, not a deliverable.
Read the profileAll 55 Success Criteria
Every Level A and AA criterion in plain language, with the failure we see most often for each.
Reference