The importance of accessibility

Accessibility is often viewed as a waste of money by many organizations. They therefore often try to get away with adherence to the minimum accessibility standards required by law. I think these organizations may be overlooking one important factor: with an ageing technology-savvy population there is a growing number of customers with some type of disability who benefit from accessibility. The disabilities often referred to when discussing accessibility are:
• Visual impairment
• Cognitive and learning impairment
• Physical impairment
• Hearing impairment

Picture of the four commonly discussed disabilities

The four commonly discussed disabilities: Physical, Cognitive, Hearing, and visual impairment

Visual impairment

Many people immediately think of blind users when discussing visual impairment, but very few are thinking of their own parents. With an ageing population there are many more aspects to visual impairment.

First off, let’s discuss the subgroup of completely blind users. These users rely on screen readers so for them it is crucial the system has been properly coded. It is therefore important to have developers who understand accessibility.

There are many designers that still don’t understand visual impairments, even though their design impacts many users. For example, roughly 7% of males have some type of color deficiency (this does not mean they are completely color blind). For women on the other hand this percentage is less than 1%. Color perception in the eye is based on three colors: red (600 nm wavelength), green (575 nm) and blue (450 nm) and if any of these cones are damaged the person will have problems distinguishing that color as well as mixes of that color. This means that designers need to take the colors selections into account.

Ageing has a significant impact on vision. A  young adult can focus on items about 15-20 cm (roughly 6- 8 inches) away, but the same focus typically is about 87 cm (34 inches) away from the eye at age 60. The retina of a 60 year old also only receives about 33% of the light a 20 year old person’s retina receives. Eye diseases also starts earlier than most people think. Macular degeneration (loss of vision in the center of the visual field) usually starts in the mid-50s and the likelihood of developing cataracts (clouding of the lens) increases with age and tends to affect people over 55. Presbyopia (diminishing ability to focus on lose objects) normally starts around the age of 40, but eventually happens to all people. While Glaucoma (optic nerve damage) usually only affects people over 60, except for African Americans were the threshold is about 40 years. Some of these diseases can be treated, but the individual may not seek medical help immediately and with our ageing population many companies will have users over 60 interacting with their products on a regular basis.

All designers should familiarize themselves with the Web Content Accessibility Guidelines (WCAG), In addition, it can be good to have the “SEE” Chrome plugin installed that allows designers to simulate different vision deficiencies, Lastly, it can also be good to calculate the contrast difference between the text and background, to ensure that the eye can distinguish between the two

Cognitive and learning impairment

When mentioning cognitive and learning impairment, most people think of the people with severe impairment, while there actually is a broad range of impairment. Cognitive and learning impairment is the most common disability in the population, and in a survey conducted by Microsoft it was found that 16% of working-age computer users in the USA have some type of cognitive or learning impairment.

The issues users with cognitive and learning disabilities encounter are often the same that affect all users, the difference is that these problems pose more severe issues for these users. Since the issues often are the same, normal usability testing can discover and prevent them. However, one thing that may need to be given a bit more attention is content writing. A good general guide line is to try to write text so an average 13 year old can understand it (this also benefit users that have English as their secondary language).

For older users the primary issue is memory. Memory impacts many mental processes such as planning, learning, decision making, etc., so it is important to present things in a clear way. In web design, guiding older users as they navigate between pages is important since they may forget what pages they have just visited. The two main ways to relieve this are 1) to have a clear navigation structure (with proper highlighting etc.) and 2) usage of conventional link colors (unvisited links are in blue and visited are in purple).

Physical impairment

People with disabilities caused from disease and injury represent the second largest group of impaired users. Similarity to cognitive and learning disabilities, there are a wide range of disabilities in this category. Most of these users have some type of assistive equipment to help them interact with the technology. However, there are still things designers can do to improve their experience. When developing a website, follow the Web Content Accessibility Guidelines (WCAG), but also try to navigate the site by only using the keyboard. If you are able to navigate the site using the ‘tab’ button, it is likely that the assistive equipment also is able to do it. Another thing to keep in mind is to make sure clickable areas are large enough so that users with disabilities are able to click them easily.

Hearing impairment

About 8.6% of the US population is hearing impaired to some extent (4.3% worldwide) and about 0.2% can’t hear at all. The hearing impaired can interact with most of the technology online since it often relies on vision and not hearing. The main thing required is to produce captions for videos or transcriptions (which also can help screen readers). This also means it may not be the best idea to use videos in an onboarding process, unless you use captions.

Our capacity to hear diminishes significantly as we grow older. 20% of people between 45-54 years have some degree of hearing impairment, but this figure rises to 75% for people between 75-79 years of age. The ability to hear high pitch sounds is affected first, so it is beneficial to use narrators with low pitched voices when speech is used as the mode of communication (Allstate, for example, avoids this problem by using a narrator with a really low pitched voice People who have become hearing impaired later on in life usually don’t know sign language, it is therefore better to provide captions than a sign language translation. Sign language also varies from country to country.

Final Thoughts

As I explained above, the number of people with impairments tends to be vastly underestimated and this population group will continue to increase as the average life expectancy increases. In addition, the subset of severely impaired users are often very loyal to companies that make their lives easier so repeat customers are higher and the churn rate is lower.

My expectations of good designers are that they can both create appealing, trendy designs that users can interact efficiently while taking accessibility into account. This approach will place a limitation on the design to some degree, but it will also make sure the design is not packed with usability issues.

Before dismissing accessibility as an additional expense, really consider what the the cost benefit ratio would be (with a good designer and developer some things are already taken care of) and what additional profit you may gain (increasing population of disabled users).


  1. Web Accessibility- A foundation for research, Simon Harper & Yeliz Yesilada
  2. Engineering Psychology and Human Performance, Christopher D. Wickens & Justin G. Hollands

© David Juhlin and, 2015

Leave a Reply

Your email address will not be published.