03 - Types of Disabilities - 01

Deque university divides Disabilities into these types:

Part 1

  • Blindness
  • Low Vision
  • Color Blindness
  • Deafblindness
  • Auditory
  • Mobility

Part 2

  • Cognitivie Disabilities
  • Dyslexia/Reading Disabilities
  • Math Disabilities
  • Speech Disabilities
  • Seizure Disabilities
  • Psychological/Psychiatric Disabilities
  • Multiple/Compound Disabilities

This is the first part summary of types of Disabilities.


The term Blindness is often used to define a total loss of vision but it may also refer to the partial blindness.

U.S. definition of blindness:

A person who has a visual acuity of 20/200 with corrective lenses or who has a field of vision (what can be seen in front of the person) that is 20 degrees in the eye that has the best vision is considered to be legally blind.

Causes of Blindness:

  • Diabetes
  • Macular Degeneration
  • Glaucoma
  • Accidents or traumatic injuries to the eye
  • Stroke
  • Retinitis Pigmentosa


πŸ’» ICT

Cannot see the digital user interface
  • Self-voicing interfaces (ATMs, kiosks)
  • Screen readersΒ 
  • Refreshable braille output devices which use screen readers
Cannot use screen readersΒ 
  • Edit the markup to make it compatible with the assistive technologies used by blind people

🏘️ Architecture

Cannot see when walking
  • Canes
  • Service animals
  • GPS-based walking instructions
  • Raised tiles on the ground
  • Eliminate low-hanging architectural features
  • Clear pathways without obstructions
Cannot see signs when walking
  • Map and geolocation applications
  • Braille labels and descriptions
  • Tactile models of the exteriors and interiors

πŸ›’ Consumer products

Cannot see user interfaces on the devices
  • Alternative interfaces with knobs
  • Audio interfaces
  • Remote control through application
Cannot see labels on packaginngs
  • Embossed braille (or braille stickers)
Cannot read money
  • Applications on mobile devices can photograph the money
  • Bills and coins could be manufactured in different sizes, shapes, or textures
  • Financial transactions via computers or mobile devices
Cannot read physical books or other printed material
  • OCR software can convert scanned images of text into digital text
  • Information can be placed online or in other digital formats to allow blind people to read the materials using their own assistive technologies

Low Vision

People with low vision can see, but their vision is still quite far from perfect even with powerful corrective lenses (e.g., unable to see well when driving or reading).


  • Blur
  • Blur with Low Contrast
  • Cataracts
  • Diabetic Retinopathy
  • Glaucoma
  • Hemianopia
  • Macular Degeneration
  • Retinal Detachment



Cannot see small text
  • Screen magnifier
  • Utilities to enhance contrast, or alter other aspects to improve legibility
  • Screen readers
  • Self-voicing interfaces (ATMs, kiosks)
  • Alternative large print versions
  • Alternative digital versions
Cannot see low contrast text
  • Software or hardware options can enhance the contrast
  • Designers can choose better color combinations

Color Blindness

Color Blindness often does not mean that a person can't see any color(very rare cases). Color Blindness refers to the inability to distinguish between certain kinds of colors.


  • Red and green (the most prevalent form)
    • Deuteranopia
    • Prootanopia
  • Blue and yellow - Tritanopia
  • Red and black
  • All colors in grayscale - very rare - Achromatopsia

Assistive technology

There aren't many assistive technologies for people with color-blindness. A company called EnChroma claims to have developed glasses that can help.

Warning for the designers
Color shouldn't be used as the only way to communicate or distinguish information.


Assistive technology

Transcripts are the only way that a person who is both deaf and blind can access video or audio content. Neither the video nor the audio is directly accessible to someone who is deaf and blind. Only digital text is accessible.


πŸ’» ICT

Text cannot be seen
  • A screen reader can convert text to braille on a refreshable braille device, or "printed" in a braille embosser
Audio cannot be heard
  • A text transcript can be converted to fereshable braille device or "printed" in a braille embosser


Auditory disabilities involve hearing impairment, hearing loss, and deafness.

Another disability in this category is Central Auditory Processing Disorder (ADP). A person with this disorder doesn’t have any hearing loss, but instead there are issues with interpreting what they hear.


  • Genetics,
  • Premature birth
  • Infections/illnesses
  • Ear trauma
  • Exposure to loud noises
  • Aging

Assistive technology

Video files usually contain audio synchronized with video itself. Time-dependent audio and video require captions. A transcript is not sufficient, because without synchronized captions, viewers can't know exactly where the transcript lines up with the video.


πŸ’» ICT

Audio cannot be heard
  • Transcript
  • Sign language interpretation
Audio portion of video cannot be heard
  • Synchronized captions with videos
  • Sign language interpretation


Speeches cannot be heard in the room
  • Sign language interpretation
  • Live captions on a monitor

🏘️ Architecture

Doorbells cannot be heard
  • Alternative visual alerts


People who have missing limbs, multiple sclerosis, cerebral palsy, stroke, partial or complete paralysis, or arthritis may experience limitations with moving their body or parts of their body.

Warning for designers
All web content must be operable no matter what method a person uses to access the computer. Whether by mouse, keyboard or any other device.

Stephen Hawking used a computer to help him speak, write, and interact with the world. He had a sensor hooked up to his glasses that detected movements in his cheek.

"All my life I have sought to understand the universe and find answers [...] I have been very lucky that my disability has not been a serious handicap. Indeed, it has probably given me more time than most people to pursue the quest for knowledge."


πŸ’» ICT

Unable to use mouse
  • Alternative keyboards, mouth sticks, single switch devices, speech recognition software and eye tracking technologies
  • Content is accessible using keyboard devices
Need mote time to interact with user interface
  • Interface designer can alert users to session timeouts, provide users with a way to adjust the time limit

🏘️ Architecture

Wheel chair users unable to use steps
  • Accessible ramps
  • Elevators
  • Accessible routes are labeled and identifiable
Wheel chair users unable to navigate through tight spaces
  • Spaces should be wide enough for everyone
  • All corridors and routes should be unobstructed
Difficulties with using doors
  • Automatic doors
  • Doors with lever-type handles/doorknobs
Seating is too small
  • Seating should accommodate a variety of body sizes

πŸ›’ Consumer products

Unable to turn pages
  • Provide printed materials in a digital format


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