Title: Cortical visual impairment: An educational perspective
1Cortical visual impairmentAn educational
perspective
- Dr. Jane Erin
- The University of Arizona
2CVI 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).
3Common 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
4Physical 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
5Cautions 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.
62. 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.
73. 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.
8Physiological 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.
9Formal assessments can document estimated acuity.
- Assessments based on gaze shift and visual
fixation can provide information about optimal
function under controlled conditions.
10Assessment 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
11Functional 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.
12Strategies 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.
13Environmental 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
14Provide 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.
15Key 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.