Testing by different access needs

Vision access needs

Part of
Accessibility tools and testing collection
Last reviewed
13 August 2026

Tools and techniques to help you identify potential barriers related to visual access needs.

Visual access needs

Visual access needs can affect how people perceive and interact with digital content. They can be associated with a range of disabilities, conditions and circumstances, and can affect people in different ways.

Examples include:

  • low vision (visual impairment that is not fully correctable)
  • blindness (little or no vision)
  • eye conditions (cataracts or glaucoma)
  • colour vision deficiency (sometimes called colour blindness)
  • migraine

These are examples rather than a complete list. People with the same condition may have different access needs, and some people may experience visual barriers without having a diagnosed condition.

Potential barriers

Visual access needs can affect people in different ways. When testing your service, consider whether people can:

  • read small or low-contrast text
  • distinguish information conveyed by colour alone
  • navigate using a keyboard or screen reader
  • read text when it is zoomed or magnified

How to test for potential barriers

Start with automated checks

Automated accessibility tools can help you identify some potential barriers. They cannot identify every accessibility issue, so use them alongside manual checks and testing with people. Automated tools work best when used collectively, so you should use all 3 together.

You could use:

  • ARC Toolkit - automated accessibility checks to identify common WCAG issues
  • axe DevTools - automated accessibility checks to identify common WCAG issues
  • WAVE Evaluation - visual accessibility evaluation to help identify issues in page content, structure and layout

Carry out manual checks

Manual checks can identify accessibility barriers that automated tools cannot.

You could use:

  • Contrast checker - check if text and other visual information have sufficient colour contrast
  • Resize text - check whether content remains usable when text is resized

Run screen reader tests

You should also test with a screen reader, to understand how people who use one might navigate your product or service.

Use personas to explore potential barriers

Personas can help you consider how people with different access needs might use your service and identify potential barriers to explore during testing. You could use HMRC's accessibility personas as a starting point. Personas are useful for considering potential barriers, but they are not a substitute for testing with real people who use your product or service.

Claudia, partially sighted magnifier user

Claudia uses screen magnification software to read content. She needs:

  • high contrast and clear text
  • keyboard navigation support
  • occasional screen reader use

View Claudia's profile and task

Ashleigh, severely visually impaired screen reader user

Ashleigh relies on screen readers full time. She needs:

  • clear page structure
  • keyboard navigation
  • meaningful alt text

View Ashleigh's profile and task