Cortical visual impairment: An educational perspective

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Cortical visual impairmentAn educational
perspective

• Dr. Jane Erin
• The University of Arizona

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CVI is a major cause of visual impairment among
children

• 21-22 of children with visual impairments in
  U.S., New Zealand, and Australia have cortical
  visual impairment (Kelley, Sanspree, and Davidson
  (2000).
• Cortical visual impairment is one of three major
  causes of newly diagnosed visual impairments in
  children, according to the Model Registry of
  early childhood visual impairment (Hatton, 2001).

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Common characteristics of CVI

• Fluctuating vision
• Reliance on peripheral vision
• Attentiveness to movement
• Preference for red and yellow
• Preference for familiar rather than novel
• Difficulty with cluttered backgrounds
• Glancing away and then toward
• Potential for improvement over time
• Visual latency

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Physical development

• Strong prognosis for visual improvement within
  first three years
• Possibility of some improvement up to 7 years
• Some children diagnosed with Delayed Visual
  Maturation regain functional vision
• Effects of intervention (as compared to
  maturation) are unknown

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Cautions in interpreting the literature

• 1. Never and Always are not appropriate for
  groups of students with CVI. These students show
  wide individual variation, and they rarely show
  all of the common characteristics.

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2. Educational programming should not be based
on etiology

• Program decisions should be based on individual
  assessment, including the functional vision
  assessment. The diagnosis suggests global
  characteristics that help determine assessment,
  not specific interventions.

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3. Compensatory approaches may be as important as
visual usage.

• Visual improvement may not result in integrated
  use of senses. Students may respond more
  immediately to information received through other
  senses.

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Physiological assessmentsGood, W., Jan, J.,
Burden, S., Sknezenski, A., Rowan, C. (2001)

• Computed tomography (CT) can show type and
  location of damage.
• Magnetic resonance imagery (MRI) is more
  sensitive than CT scan.
• Visual evoked response (VEP) maps responses over
  a wider area and can be combined with an EEG
  (Electroencephalogram) for diagnosis.

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Formal assessments can document estimated acuity.

• Assessments based on gaze shift and visual
  fixation can provide information about optimal
  function under controlled conditions.

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Assessment Scale The CVI Range

• Dr. Chris Roman, Marshall University, has
  developed a rating scale that identifies
• Characteristics of student
• Status of characteristics
• Levels 0-4 Building visual behaviors
• Levels 4-7 Embedding vision into function
• Levels 7-10 Resolution

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Functional Vision Assessments

• Must be complete over several sessions, in
  different settings and at different times of day.
• Videotaping can be used to document initial
  session and reassess vision at regular intervals.
• Should involve familiar and unfamiliar objects
  and settings.
• Near and distance responses in central and
  peripheral fields should be noted.

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Strategies for intervention(Morgan, in Lueck,
2004)

• Do vision activities at time when best visual
  function is observed.
• Simplify the task.
• Slow the presentation and provide plenty of
  response time before prompting.
• Make sure expectations are evident.
• Provide structure and consistency.
• Space the target materials to allow visual
  attention.
• Reduce background clutter and sensory
  information.

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Environmental adaptations (Morgan, in Lueck,
2004)

• Control for glare
• Minimize florescent lighting
• Place student with back toward window
• Use indirect lighting
• Reduce irrelevant sensory information (e.g.,
  background noise, odors)
• Enhance visual targets with color, light
  highlighting
• Reduce visual detail

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Provide multisensory cues and reinforcement,
according to childs preference (Morgan, in
Lueck, 2004)

• Add sound to the visual target.
• Create visual/tactile boundaries for task.
• Tap the childs arm or body on the side of an
  approaching visual stimulus.
• Encourage the student to track visual information
  with a finger.
• Use verbal cues for the beginning and ending of a
  routine.

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Key points

• Strategies can be useful with most students with
  multiple disabilities.
• Educational planning should be based on
  assessment and observation, not diagnosis.
• Consistent interventions with gradual
  generalization will be most successful.