Download Developing Vision Skills for Success with Assistive Technology

Developing Functional Vision Skills
for Success with Assistive Technology
Models of Vision
Medical/Optical Model
• detection of eye disease and visual acuity
Behavioral Model
• vision guides movement and directs action
• vision is learned
• visual skills can be improved with optometric
vision rehabilitation or vision therapy
Models of Vision
Ocular Visual Impairment (OVI)
rooted in the eyeball
Cerebral Visual Impairment (CVI)
rooted in visual pathways/connections
through the brain and the rest of the body
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The Visual Process
To enhance vision for both:
- visual input (sensory) and
- visual output (motor)
Optimal visual processing leads to:
-better sustained attention
-faster processing speed and
-superior comprehension/perception
Tools that Work
• Think developmentally – let the child’s actions
and results dictate your next step.
• Resist teaching – allow the child to explore and
discover the solutions using experimentation and
evaluation.
Tools that Work
• If an activity is difficult to perform, know when
and how to modify it so that some measure of
competence can be attained.
• Sometimes, you have to walk away from an
activity and return to it when more building
blocks to the activity are in place.
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Tools that Work
• Mistakes are not bad. Not recognizing an error or
difference makes it a bad mistake.
• Children can learn to discriminate “same” and “not same”
related to movement even before they understand
directional labels.
Laterality comes before Directionality
Knowing it on yourself allows you to project it
into space
Visual Screening
• Visual Tracking and Locating
• Convergence
• Depth Judgment
Pursuits
• Have the student stand (if possible) with their arms at their
sides and ask them to follow a small target. If they begin
with head movement, ask them to follow the target with
just their eyes.
• Hold the target approximately 16 inches from the student
and trace a circle 8 inches to either side of his/her nose at
least two times clockwise and two times counter-clockwise.
• Monitor and record the student’s ability to complete each
rotation while keeping his/her eyes fixed on the target.
Note any head or body movements made during the test.
Saccades
• Hold two fixation targets 16 inches from the student with
the targets positioned horizontally 4 inches to the right
and to the left of midline. Have the student fixate one
target and then instruct them to quickly look at the other
target and back to the first target. Repeat each cycle four
more times.
• Monitor and record any over- or under-shooting of
fixation, the ability to complete the task, and any head
or body movements.
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Nearpoint of Convergence (NPC)
• Requires a small near picture target
• Ask the student to look at the target as you move it
toward his/her nose.
• Record the distance in inches from their nose when an
eye drifts outward and/or the student reports seeing
two images. This should be no greater than 3 inches
from the tip of their nose.
• Reverse direction and record the distance in inches
from their nose when the student regains fusion of the
eyes. This should be no greater than 6 inches from the
tip of their nose.
Visual Tracking and Visual Thinking
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X
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Tracking Progress
• Goals must be achievable!
• Should include specifically what skill you are
addressing
• Include quantifiers (either a certain amount of
time or percentage of time and the amount of
assist/verbal cues needed to complete task)
• Include over how many sessions
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