VISUAL IMPAIRMENT: Glossary of Terms

Visual Impairment – A general term for any vision loss, ranging from low vision to total blindness.

Partial Blindness / Low Vision – Refers to a range of visual impairments where a person has some vision but it is not fully correctable with glasses, contact lenses or surgery.

Legal Blindness – Best-corrected visual acuity in the better eye is 20/200 or worse, or there is a severely restricted visual field (20 degrees or less). A functional definition used to determine eligibility for disability benefits and services.

Total Blindness – A complete absence of light perception

Braille – A tactile system of writing and printing with raised dots, used by people who are blind.

Additional Ways to Categorize Blindness

BY CAUSE
  • Age-related macular degeneration
  • Glaucoma
  • Cataracts
  • Genetic Conditions

BY ONSET

  • Congenital Blindness (present at birth)
  • Acquired Blindness (developing later in life due to illness or injury

Assistive Technology (AT) – Hardware or software designed to help people with disabilities perform tasks that they couldn’t otherwise perform.

SOFTWARE & DIGITAL TOOLS

  • Screen Readers – Software that reads digital text aloud using speech synthesis or converts it to a Braille display for tactile reading, allowing blind users to navigate computers, smartphones, and tablets.
  • Screen Magnifiers – Software that enlarges text, images, and other elements on a screen, often with options to customize font sizes, colors, and cursors for people with low vision.
  • Optical Character Recognition (OCR) – Technology that converts printed text into digital text, allowing screen readers to vocalize it.
  • Smart Phone and Tablet Apps – Many apps are available that use a phone’s camera to read text aloud, identify objects, or provide navigation.
  • Voice Activated Assistants – Voice control features on devices like smart speakers (e.g., Siri) help with tasks like setting reminders, controlling smart home devices, and accessing information.

HARDWARE & PHYSICAL DEVICES

  • Braille Displays and Notetakers – Devices that provide tactile Braille output for computer or digital text, as well as allowing users to take notes in Braille.
  • Video Magnifiers (CCTVs) – Closed-circuit television systems with a camera and monitor that can enlarge printed materials up to 50 times their normal size and adjust colors and contrast.
  • Smart Canes & Wearable Devices – Smart canes provide navigation assistance, while wearable devices like smart glasses can identify objects, read text, and recognize faces using a small camera and audio feedback.
  • Talking Devices – Devices such as talking clocks, thermostats, and digital audio players provide information and allow interaction through synthesized speech.
  • Low Vision Lamps & Stands – Reading lamps and stands that improve visibility for printed materials, helping individuals with low vision to read more comfortably.