Disabilities Defined

[Author: Bill Fischer]

About 47% of the U.S. population is regularly experiencing some form of disability (not including situational limitations), and about 2/3 of all internet connections are made with a mobile phone via cell signal (the baseline technology for low income populations). Photo Illustration by Bill Fischer.


Hearing disabilities include a range of hearing impairments beyond those that cannot hear at all. Providing captions and transcripts provide a lifeline to content for these individuals.

U.S. Population Statistics for Hearing Disabilities (2012)

Source: National Institutes of Health (external link)

Total (adults) 37.5 million (15%)

  • About 2 to 3 out of every 1,000 children in the United States are born with a detectable level of hearing loss in one or both ears

Blindness and Low Vision

Many individuals who are blind interact with computers using screen-reader software. Individuals who are blind cannot browse content the way sighted individuals do (by visually scanning and finding the relevant information). For them, content is experienced linearly, by tabbing through categories of information, such as, menus, links and headings.

Individuals who have low-vision or who have photosensitivity issues also can be affected by inaccessible content. The use of high contrast, audio, and logical design layout with clearly delineated sections will provide meaningful experiences for the sight impaired.

U.S. Population Statistics for Visual Disabilities (2016)

Source: National Federation of the Blind (external link)

Total (all ages): 7,675,600 (2.4%)

  • Total (16 to 75+): 7,208,700 (2.83%)

    • Age 16 to 64: 4,037,600 (2.0%)

    • Age 65 and older: 3,171,100 (6.6%)

Color Blindness

Individuals who are colorblind or who have photosensitivity issues also can be affected by inaccessible content. The use of colorblind-friendly colors, high contrast, audio, and logical, consistent layout will provide meaningful experiences for the sight impaired.

World Population Statistics for Color Blindness

Total All ages: (4.5 %)

  • 8 % of men

  • .5 % of women

  • By far the most common form is red-green colorblindness, which includes 99.999% of all instances.

  • 72% have a moderate anomaly. 38% have a severe anomaly.

  • Blue-yellow and achromatic (no color ability) color blindness is rare and includes .0001%.

This Illustration demonstrates what can happen when the color red is used as an accent. The effect is significantly subdued for a red-green colorblind person, as shown at the bottom.

One image with  a graphic popping off a gray background compared to the color-blind version where the red graphic is very dull.


According to the National Institute of Health, Photophobia is a common yet debilitating symptom seen in many ophthalmic and neurologic disorders. It is defined as an abnormal sensitivity to light, especially of the eyes, and is reported in most all forms of migraine and many neuro-ophthalmic disorders. Persons with this condition can experience migraines and flickering from images and text with high value and hue contrast (over 16:1 ratio). They will typically use accessibility features on digital devices that dim the brightness or convert screens to grayscale.

About 12% of adults experience migraines with women twice as likely to be affected. Photophobia is one of the most common symptoms of migraine.

Source: Migraine.com


Keyboard access is the most important concept when thinking about the accessibility of content for individuals with mobility disabilities. Some people have partial or no use of arms, hands or fingers. Additionally, many other individuals have limited control of their arms, others have diminishing fine motor controls. All of these individuals might have difficulty using a mouse, many only use the keyboard to navigate. Others use items such as trackballs, adaptive keyboards, head-wands, mouth-sticks, and speech recognition software.

U.S. Population Statistics for paralysis (2013)

Source: Christopher and Dana Reeves Foundation (external link)

Total all ages in the U.S. report that they were living with some form of paralysis: 5,357,970 (1.7%)

A boy pushing a man in a wheel chair in vast parking lot.


Some people have a difficult time speaking or cannot speak at all. This is an especially important population to consider as technology begins to move more towards spoken controls for interactive devices (such as Google Home and Amazon's Echo).

U.S. Population Statistics for Speech Disability (2015)

Source: National Institutes of Health (external link)

Total All Adults: 9.4 million (4 %)

  • Approximately 9.4 million (4.0%) adults report having a problem using their voice that lasted one week or longer during the last 12 months.


Many people land within a spectrum of cognitive disabilities such as ADHD and dyslexia, as well as a variety of other comprehension challenges. Disorganized and poorly written content is a barrier to accessibility. These individuals benefit from well structured, semantically organized media that provide multiple means of access that can include, text, illustrations, diagrams, video or audio. Assisted learning technologies such as screen readers, captions and video are very useful for these people with seemingly invisible disabilities.

'Harley's Story' provides a terrific case study for assistive technology and its use for the cognitively impaired (external link) from The Center of Inclusive Design and Innovation at Georgia Tech. University (linked in).

U.S. Population Statistics for Cognitive Disability (2002)

Source: Cornell University (external link)

Total All Adults: 13,474,000 million (7.5 %)

  • Civilian, non-institutionalized men and women aged 18-64 in the United States that reported a work limitation.

Temporary Disability

Sometimes disabilities are caused by known factors and full or partial recovery can be expected. This can include situations like these:

  • Where cataracts and cataract removal surgery clouds vision and cause light sensitivity.

  • Broken fingers and hands make navigating digital media challenging.

  • Tinnitus (ringing in the ears) can be caused by loud music or infections.

  • Medications can limit our ability to concentrate.

Situational Limitation

An often-overlooked area of accessibility are the needs of individuals who are temporarily unable to access media in certain ways. This can include situations like these:

  • Where audio would disturb those around us (such as on a bus or in a waiting room).

  • When we are caring for a child and cannot be focused consistently on a screen.

  • Perhaps we are just having a difficult time concentrating when we are tired.

  • Brightly lit rooms with dim computer displays or projections can make screens difficult to see.

The digital display on the left demonstrates the color dulling effect of a low-light-energy-saving mode. On the right, glare from direct sunlight can wash out the brightest digital display. These are common situational limitations

A graphic shown on a smart phone screen. one screen is very dim the other has a strip of light glare obscuring it.


The smart phone is often a person's only available access to digital media. Over 50% of web page views worldwide occur on mobile devices. Websites, documents and digital media in general, must be compatible with smart phones and slow connections to be fully accessible. Situations where mobile devices and slow connections are the only option include:

  • Low income people whose only digital device is a smart phone.

  • K-!2 students with cell-connected hotspots provided by their schools

  • Families with low-end broadband that is overladed with users.

  • People that are traveling short and long distances with cell-enable devices.

  • People that are in situations where a laptop or desktop computer is not an option (like an impromptu meeting or public venue).

The 2021 Connect K12 Connectivity Report (pdf) from a study conducted by Connected K-12 (external link) has found that, in the U.S., 41 % of K12 school districts, serving 27.6 million students, fail to meet FCC's 1 Mbps per student guideline.