Visual Disabilities

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Visual Disabilities

Visual disabilities cover a spectrum from total blindness (no light perception) to low vision and color blindness. Enabling access for users who are blind is often what people think of when they consider web accessibility. We should also consider the other varying forms of visual disabilities.

Low Vision is significant visual impairment that can’t be fully corrected with glasses, contact lenses, medication, or eye surgery.

Here are some simulated examples of low vision disorders:

  • Cataracts are cloudy areas in the lens of the eye that can cause cloudy or fuzzy vision and sensitivity to glare.

  • Glaucoma causes damage to the optic nerve, usually due to increasing pressure within the eye. This can result in a loss of peripheral vision, creating a vignette effect.

  • Macular degeneration is a disorder that affects the retina, the lining at the back of the eye where images are focused. This can cause difficulty reading and, for some, a blind spot in the central area of vision.

  • Retinitis Pigmentosa gradually destroys night vision, severely reduces side vision, sometimes referred to as tunnel vision, and may result in total vision impairment.

  • Color-blindness is a vision deficiency which affects an individual’s ability to distinguish between certain color combinations. The most common combinations are red/green and yellow/blue. About 8% of males and about 0.5% of females have some form of color-blindness.

 

Therefore, it’s important not to depend on color alone as a way to convey information. Use patterns, asterisks, or other non-color means to distinguish data.

Assistive Technology for People with Visual Disabilities

Assistive technology is any item, piece of equipment, software program, or product system that is used to increase, maintain, or improve the functional capabilities of persons with disabilities.

Some examples of assistive technology that can be helpful to those with visual disabilities are:

 

  • Screen Readers: Screen readers are used primarily by people with vision disabilities. However, they are also helpful to people with cognitive disabilities and users for whom English is a second language physical disabilities by reinforcing written content.
  • Screen Magnifiers: Screen magnifiers, such as ZoomText, allow selected parts of the screen to be magnified.
  • High Contrast: Some people with low vision experience low contrast, and therefore benefit from high contrast text and graphics.
  • Audio Description: People with low vision can benefit from audio description, which is used in video content to describe important visual details that cannot be understood from the main soundtrack alone.