Types of Disabilities & Barriers

This lesson will provide an overview of the different types of barriers faced by people with different disabilities when navigating content on a computer or the internet.  

Overview

In order to understand how accessibility and technology intersect, it is helpful to have a basic understanding of a range of disabilities and their related barriers with respect to the consumption of digital content.

Not all people with disabilities encounter barriers on the web, and those with different types of disabilities encounter different types of barriers. For instance, if a person is in a wheelchair they may encounter no barriers at all in terms of accessing your digital and print content. A person who is blind will experience different barriers than a person with limited vision. Different types of disabilities and some of their commonly associated barriers are described here. 

Blindness

Blindness does not always mean that someone cannot see at all. As with all conditions, people who are blind vary in how much they can see. It's also important to realize that not all people who are blind read Braille. Some do, while others may rely on technology to read content aloud.

People who are blind tend to face many barriers with print and digital content. For one, print content may be useless if someone has no vision at all, thus providing digital copies of your materials is a step in the right direction.

People who are blind often use screen readers or refreshable Braille to consume content. Navigating a computer is often done by use of the keyboard and not the mouse. 

Common barriers for this group include:

• visual content that has no text alternative
• functional elements that cannot be controlled with a keyboard
• overly complex or excessive amounts of content
• inability to navigate within a page of content
• content that is not structured
• inconsistent navigation
• time limits (insufficient time to complete tasks)
• unexpected actions (e.g., redirect when an element receives focus)
• multimedia without audio description

Low Vision

People with low vision are often able to see content if it is magnified. They may use a screen magnification program to increase the size and contrast of digital content to make it more visible. They are less likely to use a screen reader than a person who is blind, though in some cases they will. People with low vision may rely on the magnification or text customization features in their Web browser, or they may install other magnification or text reading software. Again, digital copies of materials provides these users the flexibility and control they need to modify the content as needed.

Common barriers for this group include:

• content sized with absolute measures that is not resizable
• inconsistent navigation
• images of text that degrade or pixelate when magnified
• low contrast (inability to distinguish text from background)
• time limits (insufficient time to complete tasks)
• unexpected actions (e.g., redirect page when an element is selected)

Color Blindness

People who are color blind are not blind at all. They have Color Vision Deficiency (CVD) which makes it difficult or impossible to distinguish between certain colors. There are several different types of color vision deficiency.

• Red-Green - People with red-green color blindness have difficulty distinguishing colors in the green-yellow-red spectrum. Red looks very similar to black and pink looks very similar to blue.
• Blue-Yellow - People with blue-yellow color blindness have difficulty distinguishing colors in the blue-yellow spectrum. Blue and violet appear greenish. Yellow appears as pink. Purple appears as red.
• Greyscale - Total color blindness results in seeing the world in greyscale.

Common barriers for this group include:

• use of color to convey meaning
• inconsistent navigation
• low contrast (inability to distinguish text from background)

Deaf and Hard of Hearing

As with blindness, people who are Deaf may experience different levels of hearing or none at all. Some people who are Deaf use sign language, and others may read lips. Regardless, most people who are Deaf tend to face barriers where audio content is presented without text-based alternatives. Those who are Deaf and blind will face many more barriers, including those described for people who are blind. For those who communicate with American Sign Language (ASL) or other sign languages (e.g., langue de Signes Quebecoise – LSQ), the written language of a website may produce barriers similar to those faced when reading in a second language.

Common barriers for this group include:

• audio without a transcript
• multimedia without captions or transcript
• lack of ASL interpretation (for ASL/Deaf community)

Mobility-related Disabilities

Mobility-related disabilities are quite varied. As mentioned earlier, one could use a wheelchair and face no significant barriers to digital content. However, those who have limited use of their hands or who have fine motor impairments that limit their ability to target elements on the web with a mouse may not use a mouse at all. Instead, they might rely on a keyboard or perhaps their voice to control movement through website along with switches to control mouse clicks.

Common barriers for this group include:

• clickable areas that are too small
• functional elements that cannot be controlled with a keyboard
• time limits (insufficient time to complete tasks)

Cognitive & Learning Disabilities

Learning and cognitive-related disabilities can be as varied as mobility-related disabilities, perhaps more so. These disabilities can range from a mild reading related disability to very severe cognitive impairments that may result in limited use of language and difficulty processing complex information. For most of the disabilities in this range, there are some common barriers and others that only affect those with more severe cognitive disabilities.

Common barriers for this group include:

• use of overly complex/advanced language
• inconsistent navigation
• overly complex or excessive amounts of content
• time limits (insufficient time to complete tasks)
• unstructured content (no visible headings, sections, topics, etc.)
• unexpected actions (e.g., redirect when an element receives focus)

More specific disability-related issues include:

• reading: text justification (inconsistent spacing between words)
• reading: images of text (not readable with a text reader)
• visual: visual content with no text description
• math: images of math equations (not readable with a math reader)

Everyone

While we generally think of barriers in terms of access for people with disabilities, there are some barriers that impact all types of users, though these are often thought of in terms of usability. Usability and accessibility go hand-in-hand. Adding accessibility features improves usability for others. Many people, including those who do not consider themselves to have a specific disability (such as those over the age of 50) may find themselves experiencing typical age-related loss of sight, hearing, or cognitive ability. Those with varying levels of color blindness may also fall into this group.

Some of these usability issues include:

• link text that does not describe the destination or function of the link
• overly complex content
• inconsistent navigation
• low contrast
• unstructured content

• How People with Disabilities Use the Web Links to an external site. - this is a great resource if you want to learn more about how certain types of conditions impact using the web, specifically, this is a strong resource in that it provides scenarios as examples to learn from.