Cortical Visual Impairment

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CVI

• Cortical Visual Impairment

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• The current leading cause of visual impairment
  among children is not a disease or condition of
  the eyes, but cortical visual impairment
  (CVI)also known as cerebral visual impairmentin
  which visual dysfunction is caused by damage or
  injury to the brain.

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Medical definition

• Cortical visual impairment (CVI) may be defined
  as bilaterally diminished visual acuity caused by
  damage to the occipital lobes and or to the
  geniculostriate visual pathway.
• CVI is almost invariably associated with an
  inefficient, disturbed visual sense because of
  the widespread brain damage.

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Educational definition

• Cortical visual impairment (CVI) is a
  neurological disorder, which results in unique
  visual responses to people, educational
  materials, and to the environment.
• When students with these visual/behavioral
  characteristics are shown to have loss of acuity
  or judged by their performance to be visually
  impaired, they are considered to have CVI.

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• During the last several decades, our
  understanding of vision has markedly improved. It
  is now realized that vision is not a single sense
  but a combination of complex senses, involving
  most of the brain in its process.
• In different locations of the brain, there are
  specialized areas for distance vision,
  recognition of faces, objects, colors, contrast,
  and movement.

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Cause

• CVI is caused by widespread damage to the brain,
  which affects most of the specialized visual
  centers, resulting in a damaged, inefficient
  visual sense.

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• The medical definition of CVI is not well
  understood by non-medical professionals.
• While acuity testing is difficult in the young
  and disabled for physicians, it is even more
  difficult for teachers.
• Also, there are many children with visual
  problems similar to CVI, except they have normal
  acuity.
• This visual condition is called "cortical visual
  dysfunction" (CVD).
• The educational management of children with CVI
  and CVD is similar.

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CVI is suspected by

• a normal or close to normal eye examination
• a medical history which includes neurological
  problems and
• the presence of unique visual/behavioral
  characteristics.

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Unique visual/behavioral characteristics

• Normal or minimally abnormal eye exam.
• CVI may co-exist with optic nerve atrophy,
  hypoplasia or dysplasia and ROP.
• Difficulty with visual novelty.
• Prefers to look at old objects, not new, and
  lacks visual curiosity.
• Visually attends in near space only.
• Difficulty with visual complexity/crowding.
• Performs best when one sensory input is presented
  at a time, when the surrounding environment lacks
  clutter, and the object being presented is
  simple.
• Non-purposeful gaze and/or light gazing
  behaviors.
• Distinct color preference.
• Preferences are predominantly red and yellow, but
  could be any color.

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• Visual field deficits.
• Not so much the severity of the field loss, but
  where the field loss is located.
• Visual latency.
• Visual responses are slow often delayed.
• Attraction to movement, especially rapid
  movement.
• Absent or atypical visual reflexive responses.
• Fails to blink at threatening motions.
• Atypical visual motor behaviors.
• Look and touch occur as separate functions, e.g.,
  child looks, turns head away from item, then
  reaches for it.
• Inefficient, highly variable vision.

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Strategies

• Slow down. 
• Allow time for student to respond.
• Simplify the task.
• Schedule visual experiences for the time of day
  when the student demonstrates optimal visual
  functioning. 

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•  5. Be specific about what you want the student
  to see and to do.
• 6. Sequence the task.
• 7. Provide structure and sameness in each
  presentation.

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Environment

1. Provide an environment that is free from visual
   clutter.
2. Be sure that the work surface does not have a
   pattern. 
3. Be sure that the learning environment has only
   essential visual information, especially on
   background surfaces and spaces.

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Materials

1.  Enhance the visual targets.
2. Keep visual information simple, constant, and
   predictable.
3. Use real objects in natural sequences to aid in
   the understanding of the real visual environment.

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To summarize

•  CORTICAL VISUAL IMPAIRMENT
• Cortical Visual Impairment (CVI) is a
  temporary or permanent visual impairment caused
  by the disturbance of the posterior visual
  pathways and/or the occipital lobes of the brain.
  The degree of vision impairment can range from
  severe visual impairment to total blindness. The
  degree of neurological damage and visual
  impairment depends upon the time of onset, as
  well as the location and intensity of the insult.
  It is a condition that indicates that the visual
  systems of the brain do not consistently
  understand or interpret what the eyes see. The
  presence of CVI is not an indicator of the
  child's cognitive ability.

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• What all should be in a CVI/Functional Vision
  Evaluation Kit?
• September 1, 2008 Created by Diane Sheline,
  CTVI, CLVT, dianesheline_at_yahoo.com    updated
  09/18/2008
• CVI FUNCTIONAL VISION EVALUATION KIT  
   Penlight/flashlight with different colored
  caps/filters    Flashlight with different
  colored filters    Mylar Pompomspreferably red
  and yellow    Cereal and other real or
  simulated food itemsFruit Loops, red licorice,
  banana, Cake Decors and Cheerios
•     Mylar paper or wrapping paperpreferably
  red and yellow
•     Soap bubbles, for blowing    Measuring
  tape    Slinkysolid colors and plastic
•     Hidden pictures or I Spy book    Variety
  of different colored balls in a variety of
  sizes    A black, light-absorbing background2
  yards of black fabric, Invisiboard, or other
  similar material/board
•     2 yards of white fabric    Variety of
  flashing lightsincluding bikers safety light,
  snap-on-spoke light clips, etc.
•     Supplementary lightsuch as a clamp on
  directional light
•     Variety of yellow and red toys such as
  Elmo, Big Bird, reflective mirror, balls, etc.,
  or sets of red and/or yellow objects to be
  sorted into same colored containers
•     Black and white toys    Mirrors

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• MORE MATERIALS
•  Reflective materials mylar balloons, pom poms,
  shakers, etc.
• Suspended or moving objects (windsock, ball on
  elastic cord, etc.
• Slap bracelets in reflective red and yellow
• Blinking ice cubes attached to elastic ring
  bandor any blinking lights that can be
  thoroughly cleaned/washed
• Personal Laser Light Show fan
• Spinning Pinwheel on long stick (yellow or red
• Variety of sunglassesBabyBanz, yellow clip-ons,
  overglasses sunglasses, etc.
• Croakiesadjustable straps to hold glasses in
  place
• Visors or brimmed caps
• Items from everyday routines in solid
  colorscups, spoons, toothbrushes, etc.
• Container of Lysol wipes
• Notebook of variety of CVI articles for parents
• Rolling suitcase to hold it all in
• Extension cord(s)
• Extra Batteries (AA and AAA)
• Selected equipment and materials from APH
  includingo    Regular or Mini Light Box with
  clear and colored overlays and colored acrylic
  objectso    ToAD Tools for Assessment and
  Development of Visual Skillso    Invisiboardo  
   ISAVE Visual Field/Acuity Grido    Sensory
  Learning Kit

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• What will cause the use of the vision?
• rut in the snow

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• http//www.aph.org/cvi/advo.html
• http//www.aph.org/cvi/index.html
• http//dianesheline.wordpress.com/toolbox/techniqu
  es-and-strategies-to-use-with-students-with-cortic
  al-visual-impairment/