The Lumen Chi Accessibility Foundations defines how to make web content more accessible to people with disabilities.

Accessibility involves a wide range of disabilities, including visual, auditory, physical, speech, cognitive, language, learning, and neurological disabilities. According to the CDC, 1 in 4 adults in the United States have some type of functional disability.

Lumen is required to meet the Web Content Accessibility Guidelines (WCAG 2.0), Conformance Levels A and AA success criteria. These guidelines and their success criteria will also satisfy the Revised Section 508 of the U.S. Rehabilitation Act (as of January 18, 2018).

The content within the Lumen Chi Accessibility Foundations is derived from the WCAG principles, guidelines, and success criteria. Although these WCAG guidelines cover a wide range of issues, they are not able to address the needs of people with all types, degrees, and combinations of disability. These guidelines also make web content more usable by older individuals with changing abilities due to aging and often improve usability for users in general.

Key accessibility concepts

Using the keyboard

The website or application must be completely usable through a keyboard. There can be nothing which requires a mouse. Blind users who rely on screen readers navigate by using the keyboard. In addition, some users who see the screen perfectly well have impaired motor skills which make it difficult or impossible to control a mouse.

Page structure

Well-structured content allows more efficient navigation and processing. Use HTML and WAI-ARIA to improve navigation and orientation on web pages and in applications. Mark up should include page regions, labeling regions, headings, and content structure.

Color and sensory

Enables people with visual impairments or color vision deficiencies to interact with digital experiences in the same way as non-visually-impaired people.


Images must have text alternatives that describe the information or function represented by them.


Genuine text is much more flexible than images. Text can be resized without losing clarity, and background and text colors can be modified to suit the reading preferences of users. Images are more likely to distort and pixelate when resized.

Links and forms

Users usually prefer simple and short forms. Only ask users to enter what is required to complete the transaction or process. If irrelevant or excessive data is requested, users are more likely to abandon the form.


Accessible tables need HTML structural markup that indicates header cells and data cells and defines their relationship. Assistive technologies use this information to provide context to users.


  • Time-based Media: Provide alternatives for time-based media.
  • Distinguishable: Make it easier for users to see and hear content including separating foreground from background.
  • Enough Time: Provide users enough time to read and use content.
  • Seizures: Do not design content in a way that is known to cause seizures.

About assistive technologies

Technologies that allow people with disabilities to use a resource are known as assistive technologies. Perhaps the most commonly thought of type of assistive technology for the web are screen readers, which proccess the visible (and sometimes invisible) elements on the screen and read the information aloud to the user. The three most popular screen readers are JAWS, NVDA and VoiceOver (iOS). Other examples of assistive technologies used on the web include Braille translation devices, screen magnifiers, closed captioning, and specialized keyboards.


The Four Principles of Accessibility (POUR) and the Guidelines

Anyone who wants to use the web must have content that is:


Information and user interface components must be presentable to users in ways the can perceive.

Ask: Can a user get a context to their senses?

  • 1.1 Text-alternatives: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
  • 1.2 Time-based media: Provide alternatives for time-based media.
  • 1.3 Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
  • 1.4 Distinguishable: Make it easier for users to see and hear content including separating foreground from background.

User interface components and navigation must be operable.

Ask: Can a user successfully use controls, buttons, navigations and other interactive elements?


Information and the operation of user interface must be understandable.

Ask: Is the presentation and format consistent, predictable in its design and usage patterns, concise, multimodal, and appropriate to the audience in its voice and tone?


Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

Ask: Is the website compliant with the standards, and does it work with the assistive technologies - including websites, online documents, multimedia and other information formats?

  • 4.1 Compatible: Maximize compatibility with current and future user agents, including assistive technologies.