Visual impairment（视觉障碍）carries with it a reduced or restricted ability to travel through one’s physical
and social environment until adequate orientation and mobility skills have been established. Because
observational skills are more limited，self-control within the immediate surroundings is limited. The visually
impaired person is less able to anticipate hazardous situations or obstacles to avoid.
Orientation refers to the mental map one has of one’s surroundings and to the relationship between self and
that environment. The mental map is best generated by moving through the environment and piecing together
relationships，object by object，in an organized approach. With little or no visual feedback to reinforce this mental
map，a visually impaired person must rely on memory for key landmarks and other clues. Landmarks and clues
enable visually impaired persons to affirm their position in Space.
Mobility，on the other hand，is the ability to travel safely and efficiently from one point to another within
one’s physical and social environment. Good orientation skills are necessary to good mobility skills. Once
visually impaired students learn to travel safely as pedestrians（行人）they also need to learn to use public
transportation to become as independent as possible.
To meet the expanding needs and demands of the visually impaired person，there is a sequence of instruction
that begins during the preschool years and may continue after high school. Many visually impaired children lack
adequate concepts regarding time and space or objects and events in their environment. During the early years
much attention is focused on the development of some fundamental concepts，such as inside or outside，in front of
or behind，fast or slow，movement of traffic，the variety or intersections，elevators or escalators，and so forth.
These concepts are essential to safe，efficient travel through familiar and unfamiliar settings，first within
buildings，then in residential neighborhoods，and finally in business communities.