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When assessing the mobility
skills of students with low vision, special attention needs to be given
to evaluating their visual skills. Explore not only how much students can
see but how well they are using visual information. Are they being proactive
travelers, anticipating and planning ahead? For some students, visual analysis
of the environment is a skill that would not be learned unless a systematic
and sequenced program of instruction is provided. Orientation and mobility
classes provide an ideal setting to assess and teach visual analysis of
the environment, since it takes place in a variety of settings, both indoors
and outdoors, familiar and unfamiliar and under different types of lighting
and weather conditions.
We believe that students
who have learned to become visually efficient and at the same time use
other sensory cues, are likely to become more knowledgeable of the surrounding
environment, have greater awareness of what lies ahead and have a more
pleasurable visual experience.
The term low vision includes
students with a wide spectrum of visual abilities. For students who are
not able to visually identify common environmental objects a more basic
program of visual stimulation needs to be implemented. However, for the
purpose of this presentation, we will focus on those students who are already
able to visually identify common environmental objects.
Just as our students with
low vision learn to use a cane to preview space two paces ahead, we can
also teach them to VISUALLY PREVIEW their surroundings. Visual preview
of the environment allows students to:
l. Anticipate the presence
of objects, which can result in fewer mobility-related incidents, such
as tripping, bumping, etc.
2. Increase their visual
selection of landmarks and locate them from greater distances.
3. Travel more confidently
while monitoring the everchanging environment, with increased comfort and
reduced stress level
Usually, neither the long
cane or use of vision alone can solve all the child's mobility problems.
The cane can be used for detecting low lying obstacles and depth changes,
while vision is now freed from looking on the ground and can be used to
detect obstacles, interpret orientation cues and appreciate visual aesthetics.
A practical example of vision and the long cane working together is a child
approaching descending stairs. He uses visual cues, such as successive
triangular shapes, as illustrated in this slide, to identify, locate and
estimate the depth of the steps. Then, the long cane assists in providing
information regarding whether he is perpendicular to the edge as well as
locating the first and last step.
Following are some specific
skills involved in visual analysis of the environment:
1. Basic visual motor skills
2. Use of color/contrast,
shape and contextual cues.
3. Blur interpretation.
4. Visual closure.
1. Basic Visual Motor Skills:
three of the most common visual skills we emphasize during mobility are
scanning, tracing and tracking.
a- scanning is moving the
head and eyes to search for a target. An example of scanning is when we
walk down the street while searching for a house address. We move our head
towards the buildings and search with our eyes around the doors to locate
the number and then read it. When searching for a vertical object, such
as a traffic light pole, we should scan horizontally until the target crosses
our visual field. We should scan vertically, on the other hand, for objects
positioned horizontally, such as signs on a wall.
b- tracing implies visually
following a stationary line. We trace, for example, in a hallway when we
are told to go to the third office on the right. We keep our eyes on the
right wall, following it visually as we count one, two, three doors.
c- tracking refers to visually
following a moving target. We can track cars at a corner to see if they
are turning in front of us, or people in line at the post office or bank,
so that we know when it is our time to move to the service window.
2. Color/contrast, shape
and contextual cues. We can recognize objects based on their distinctive
features, such as color and shape and the context in which they are located.
In the U.S., for example, a rectangular blue object, about 1 m high, located
on the sidewalk is likely to be a mailbox. Some students, however, need
to learn to question themselves when looking at an object to take full
advantage of this information. They would ask themselves: what color is
this object? what shape is it? where is it located?
Color contrast cues between
sidewalk and street can warn a student of the approaching corner, for example,
and identifying shapes can assist in recognizing buildings by their distinctive
features.
3. Blur interpretation. This skill allows students who can already identify objects to do so but at greater distances. A typical example is the student who cannot see facial details but still recognizes friends from a distance by cues such as height, hair color, and their distinctive walk. A strategy for teaching blur interpretation is to have students locate objects before they can actually identify them. As an example, here is a slide of two common objects. Ask them to describe their features, shape, color and location. Then, have them walk towards the object as close as they need to, to identify it. Once more, have them walk back and check out how it looks from a distance. If the students have optical devices, they may not need to walk up to the object but use the telescope to confirm what the object is.
4. Visual closure. There
are many instances when objects in the environment are partially blocked
or obscured, such as the car shown in the slide, partially hidden by a
wall in front of it. For the child with low vision, this skill is especially
helpful when objects appear to them as partially visible due to glare,
scotomas or other visual field limitations. We need to teach students to
look for the available pieces of information, relying on visual memory.
They need to match what they see with what it could be, just like putting
together a puzzle. Then, taking into consideration the environment and
location of the object, they can determine what it is.
Mobility is filled with
situations that require visual closure. Take the example of a student who
can read store signs. However, he may not see the whole word because of
tree branches partially covering it , as shown in this slide. If he already
knows the name of the store ahead of time, he will be able to fill in the
missing parts of some letters by using visual closure.
If students need to develop
this skill, there are many activities and games we can play. One game "I
cover, You discover" can be found in the handout and addresses this skill.
The O&M therapist covers part of a common object or photograph and
asks the student to use the remaining visual cues available to identify
it.
In the same way we plan and
carefully sequence the teaching of cane skills, visual analysis of the
environment should also be taught in a systematic and sequential manner.
Following are some guidelines that may assist in planning and teaching
visual efficiency:
1. Gather important background
information: the first step is to identify your student's level of visual
functioning and plan accordingly. Some things you need to know are the
child's eye condition and functional implications, the effects of glare,
light adaptation, depth perception, visual cognitive level, visual motor
skills, and whether visual cues are used in a systematic, reliable manner
in various environments. A combination of medical and eye records, interviews
and your own assessment would give you a good starting point.
2. Teach isolated skills
and gradually integrate them: When initially teaching two-point touch,
for example, the student may begin practicing it going back and forth in
a long, empty hallway, not focusing on anything else. In the same way,
we need to teach basic visual skills first and then begin to integrate
them. To teach visual scanning, for example, we can ask the student to
walk down a hallway, popping balloons hanging from the ceiling. Once the
skill is learned, it may be applied outdoors to locate landmarks at eye
level or to warn about overhanging branches.
3. Follow the visual developmental
sequence: the student's cognitive abilities have to be taken into consideration
for successful planning. Students should not be required to perform visual
tasks beyond their her mental age. For example, if the child has not yet
learned to identify basic geometric shapes, he/she may not be ready for
learning high perceptual skills, such as blur interpretation or visual
closure.
4. Monitor and critique
visual performance: observing the student's natural head and eye movements
from different positions supplies necessary information to provide accurate
feedback. For example, if the instructor notices that the student looks
down to the ground, even when using the cane, instruction to encourage
systematic scanning will be necessary. A game where the student acquires
points for identifying various objects while walking a route may be a good
strategy.
Make it meaningful, motivating
and fun: plan activities that are challenging
enough for the student,
but still attainable. With success comes increased interest and motivation
to use vision. The O&M specialist is in a unique position to teach
the practical applications of different visual skills through games and
functional activities. For example, visual tracking can be applied in a
variety of interesting settings, from following clerks in a store to enjoying
animal's movements at the zoo.
We have prepared a handout of strategies that can be used either for assessment of instructional purposes. They are presented in general terms, so that the level of difficulty can easily be adjusted to the student's abilities and needs. Some of those activities involve the use of photographs of common environmental objects. An O&M photo library can be developed to address specific mobility concepts. The Photo Library may include enlarged, laminated color photos of common environmental objects, such as a parking meter, mailbox, fire hydrant, crosswalk lines, stop sign and traffic light. The photos can be then enlarged and laminated . I brought two copies of a basic Photo Library for you to look at after the presentation.
Finally, I would like to
share with you some of the activities and games you will find in the handout:
* THE WALKING CHECKLIST:
Instructor and/or student create a list of common environmental objects
that can be found in a particular environment. The student then travels
in the area and checks off those objects found as soon as he/she sees them
(One point for each item found). A variation on the theme is to select
a group of photographs representing the objects one expects to find in
a particular area and then walk around trying to find them.
* REAL ESTATE GAME: Pretend
the student is planning to move to a new neighborhood and is looking for
a house. The real estate agent/instructor provides the student with visual
cues to locate the houses for sale in the area (e.g., visual maps, use
of telescopes, address numbering systems can be incorporated into this
game).
These are just examples
of fun, meaningful activities that incorporate and promote the use of vision
while traveling. He hope that they will serve as a starting point for instructors
to create their own strategies to incorporate vision in a consistent and
sequential manner into everyday mobility lessons.