Clearing Our Path

Creating accessible environments ­for people with vision loss

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Glossary

accessible design:
Design that provides a level of access for people with disabilities. Accessible design is a stigmatized solution, in that people with disabilities are often accommodated separately from the general public. Universal design is preferable to accessible design. Accessible design is also known as barrier-free design.
accessible pedestrian signal (APS):
Accessible pedestrian signals are devices used at intersections and pedestrian crosswalks to provide auditory, visual, and tactile information for people with vision and/or hearing loss, to assist them in crossing streets independently.
age-related macular degeneration (AMD):
A degenerative eye disease that causes loss of central vision. AMD is the leading cause of vision loss in Canada.
attention TWSI:
A tactile walking surface indicator (TWSI) that calls attention to key hazards, such as the start of a staircase or the edge of a platform in a subway station. Also known as warning TWSI.
audible signs:
Signs that present information typically found on print signs via synthetic speech or pre-recorded voice.
blended curb:
A blended curb is a curb with a built-in ramp that creates a graduated descent towards a road surface. Some blended curbs may have no lip at all (in other words, a completely blended curb-to-road transition) for the benefit of people using wheelchairs.
brightness contrast:
The difference in brightness between one object or surface and another. The greater the difference in brightness levels, the greater the contrast. Also known as luminance contrast.
cane detectable:
An object that protrudes from walls or freestanding supports by more than 100mm can be said to be cane detectable when it is located 680mm above the walking surface, or below this level. If an object protrudes at a level higher than 680mm and below 2030mm, it can be made cane detectable if there is a railing, planter, or other cane-detectable barrier placed at or below 680mm from the walking surface.
cataract:
A clouding of the lens of the eye.
colour contrast:
The degree of difference between one colour and another on the colour wheel. The more visually different the colours, the greater the contrast.
deafblind:
Deafblindness is a combination of both hearing and vision loss. Some people who are deafblind may have some hearing and some sight. Others may have no hearing and some sight, or the opposite. Still others may have no hearing or vision at all.
echolocation:
A process by which someone with vision loss will make or use noise and listen for the reflected sound to obtain information about the built environment. Someone may tap a white cane or snap their fingers to make reflected sounds that may help them to detect the size of a room, the presence of corridors, or the proximity of structural barriers, for example.
electronic travel aid (ETA):
A mobility device that emits energy waves to detect what is in the environment within a certain range. The ETA will process reflected information and provide it to the user, usually through vibrations, sounds, or voice announcements. ETAs may operate on laser or sonar waves, and today, global positioning system technology is also used.
glaucoma:
A group of eye diseases associated with damage to the optic nerve.
guidance TWSI:
A tactile walking surface indicator (TWSI) that provides information about the direction of travel through open spaces. Guidance TWSIs are designed to guide a person on a designated path of travel. They are also known as wayfinding TWSI.
handrail:
A railing that people use for support or guidance in the built environment. Handrails typically occur on staircases and ramps, on escalators and moving walkways, and in elevators.
legal blindness:
In Canada, where normal vision is 20/20, legal blindness is defined as a visual acuity (with best correction in the better eye) equal to or less than 20/200 or a visual field extent of less than 20 degrees in diameter.
long white cane:
The white cane that is most often used by people with vision loss for mobility. The long white cane assists with object detection and depth perception, and provides advance knowledge of gradient changes and upcoming barriers or dangers in the path of travel. Typically the long white cane is swept or tapped back and forth across the path of travel.
low vision:
Vision loss that cannot be corrected by standard eyeglasses, contact lenses, medication, or surgery.
mobility:
The ability to move about or navigate a space from one point to another.
nosing:
A nosing is the horizontally projecting edge of a stair tread. It may also include the shield covering this area.
orientation:
The process by which someone with vision loss determines where they are in a space at any given moment.
path of travel:
A path of travel is any space in a facility where a person might reasonably be expected to move from one point to another. An accessible path of travel is one that is designed to accommodate all users.
peripheral:
Side vision. The ability to see objects and movement outside of the direct line of vision. residual
sight:
Residual sight means any vision that a person with vision loss has and can use. Residual sight may include light perception. Most people with vision loss have some degree of residual sight.
riser:
A riser is the vertical face of a step.
sidelight:
Sidelights are framed glass windowpanes that do not open and are positioned on either side of a door.
sighted guide technique:
A mobility technique whereby a person with vision loss uses a sighted escort to travel; it typically is used in crowded or unfamiliar situations, or when a person has recently lost their vision. In this technique, the person with vision loss will gently grasp a sighted guide’s arm from behind, and will stand about half a step behind. The sighted guide and the person with vision loss will then walk comfortably in tandem.
sound glare:
Inappropriately high levels of reflected and ambient sound that interfere with the process of locating an auditory cue. Sound glare can confuse and tire a listener. Also known as sound masking.
sound shadow:
The blocking or distortion of useful sounds by a solid object located between a sound source and a listener. In some cases, sound shadows can cause a person who is used to relying on specific sound cues for mobility to become disoriented, and in other cases, sound shadows may be beneficial and assist with orientation.
tactile:
If something is tactile, it can provide information by touch. An accessible built environment might employ tactile ground surfaces, tactile maps, and tactile signs.
tactile map:
A map with raised (tactile) lines and characters. In a building, tactile maps can show floor plans and building cross-sections and indicate the principal paths of travel and services on each floor. Tactile maps might be small and portable (given to a user as a handout) and/or posted as directional signage in a building.
tactile sign:
A tactile sign is any sign that can be read by touch. Braille, raised print, and raised symbols or pictograms are all examples of tactile signs.
tactile warning surface indicator (TWSI):
A tactile walking surface indicator is a standardized walking surface that conveys information to people with vision loss through texture, and, occasionally, sound.
tread:
A tread is the horizontal face of a step.
universal design:
The design of spaces and buildings to be usable by everyone. The seven principles of universal design are:
  • Equitable use: The design is useful and marketable to people with diverse abilities.
  • Flexibility in use: The design accommodates a wide range of individual preferences and abilities.
  • Simple and intuitive in use: Use of the design is easy to understand, regardless of the user’s experience, knowledge, language skills, or current concentration level.
  • Perceptible information: The design communicates necessary information effectively to the user regardless of ambient conditions or the user’s sensory abilities.
  • Tolerance for error: The design minimizes hazards and the adverse consequences of accidental or unintended actions.
  • Low physical effort: The design can be used efficiently and comfortably with a minimum of fatigue.
  • Size and spaces for approach and use: Appropriate size and space are provided for approach, reach, manipulation, and use, regardless of a user’s body position, size, posture, or mobility.
(Source: North Carolina State University, The Centre for Universal Design)
vision loss:
Vision loss is a term that includes people who experience a total or partial loss of vision. It also includes people who are deafblind.
visual field:
The complete area of vision that includes what is seen above, below, to the sides and in the centre. There is a central visual field (directly in front of us), and a peripheral visual field (that which we perceive in our "side" vision).
wayfinding:
The process of using cognitive and perceptual information to get from one destination to another.
wayfinding design:
Organizing the built environment to provide useful information for wayfinding. Environments that include universal design principles in wayfinding design take into account all the human senses and all modes of travel.