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
The major causes of CVI are
asphyxia, perinatal hypoxia ischemia ("hypoxia": a lack of sufficient
oxygen in the body cells of blood; "ischemia": not enough blood supply
to the brain), developmental brain defects, head injury, hydrocephalus,
and infections of the central nervous system, such as meningitis and encephalitis.
Initially, children with CVI
appear blind. However, vision tends to improve. Therefore, Cortical Visual
Impairment is a more appropriate term than Cortical Blindness. A great
number of neurological disorders can cause CVI, and CVI often coexists
with ocular visual loss so the child should be seen by both a pediatric
neurologist and a pediatric ophthalmologist. The diagnosis of Cortical
Visual Impairment is a difficult diagnosis to make. It is diagnosed when
a child has poor or no visual response and yet has normal pupillary reactions
and a normal eye examination. The child's eye movements are most often
normal. The visual functioning will be variable. The result of an MRI
(Magnetic Resonance Imaging) in combination with an evaluation of how
the child is functioning visually, provide the basis for diagnosis.
Children with CVI have different
abilities and needs. The presence of and type of additional handicaps
vary. Some children have good language skills and others do not. Spatial
confusion is common in children with CVI because of the closeness of the
occipital and pariental lobes of the brain. Habilitation should be carefully
planned. A full evaluation by a number of professionals is essential.
The evaluation team could include: teachers (of the visually impaired
or severely handicapped), Physical Therapists (PT's), Occupational Therapists
(OT's), Speech Therapists, and Orientation and Mobility Specialists.
of visual function demonstrated by children with CVI
- Vision appears to be variable:
sometimes on, sometimes off; changing minute by minute, day by day.
- Many children with CVI may
be able to use their peripheral vision more effectively than their central
- One third of children with
CVI are photophobic, others are compulsive light gazers.
- Color vision is generally
preserved in children with CVI (color perception is represented bilaterally
in the brain, and is less susceptible to complete elimination).
- The vision of children with
CVI has been described much like looking through a piece of Swiss cheese.
- Children may exhibit poor
depth perception, influencing their ability to reach for a target.
- Vision may be better when
either the visual target or the child is moving.
The behaviors of children with CVI reflect their adaptive response
to the characteristics of their condition
- Children with CVI may experience
a "crowding phenomenon" when looking at a picture: difficulty differentiating
between background and foreground visual information.
- Close viewing is common,
to magnify the object or to reduce crowding.
- Rapid horizontal head shaking
or eye pressing is not common among children with CVI.
- Overstimulation can result
in fading behavior by the child, or in short visual attention span.
- The ability of children
with CVI to navigate through cluttered environments without bumping
into anything could be attributed to "blindsight", a brain stem visual
- Children are often able
to see better when told what to look for ahead of time.
- Children with CVI may use
their peripheral vision when presented with a visual stimulus, appearing
as if they are looking away from the target.
- Some children look at an
object momentarily and turn away as they reach for it.
statements are not true, according to current knowledge in the field:
- Children with CVI are visually
inattentive and poorly motivated.
- All children with CVI will
have cognitive deficits.
- CVI is not a true visual
impairment. Children with CVI are totally blind.
- Children whose visual cortex
is damaged are Cortically Blind.
- A great deal of energy
is needed to process information visually. The child might tire easily
when called upon to use his visual sense. Allow for intermittent "break"
- Positioning is important.
Keep the child comfortable when vision use is the goal in order that
"seeing" is the only task.
- Head support should be provided
during play or work sessions, to avoid involuntary shifting of the visual
- Try many different positions
to find the one in which the child feels most secure. Infants and toddlers
will demonstrate when and where they see best by their adaptive behaviors.
- If the child needs to use
a lot of energy for fine motor tasks, work on fine motor and vision
separately, until integration of the modalities is possible.
- The simpler, more constant
and more predictable the visual information, the better the child with
CVI is likely to deal with it. Keep toys and environment simple and
uncluttered. Use books with one clear picture on a contrasting simple
- Use familiar/real objects
(bottle, bowl, plate, bath toy, diaper, cup, spoon, favorite toy) one
at a time. Familiarity and simplicity are very important.
- Since the color system is
often intact, use bright fluorescent colors like red, yellow, pink,
and orange. Colored mylar tissue seems to evoke visual responses.
- Repetition is very helpful:
use the same objects and same process each time to provide familiarity
and security for the child. Familiarity breeds response.
- Look for toys and activities
that motivate the child.
- Vision is often best stimulated
when paired with another sensory system. For example, auditory cues
from the handling of mylar may help attract the child's attention.
- Introduce new and old objects
via touch and verbal description.
- Try different lighting situations
to assess optimal conditions for viewing. Try locating a light source
behind, and/or to the side of the child.
- Try moving the target that
you want the child to see. Try different visual fields.
- Allow lots of time for the
child to see and to respond to what is being seen.
- Learn to interpret each
child's subtle response cues: such as changes in breathing patterns,
shifts of gaze or body position, etc.
"When a child with CVI needs
to control his head, use his vision, and perform fine motor tasks, the
effort can be compared to a neurologically intact adult learning to knit
while walking a tightrope."
1. "Observations on the Habilitation
of Children with Cortical Visual Impairment"; Groenveld, M.; Jan, J.E.;
Leader, P., Journal of Visual Impairment and Blindness, January, 1990.
2. "Visual Behaviors and Adaptations
Associated with Cortical and Ocular Impairment in Children"; Jan, J.E.;
Groenveld, M.; Journal of Visual Impairment and Blindness, April 1993,
American Foundation for the Blind.
3. Video: "Issues in Pediatric
Ophthalmology: Cortical Visual Impairment (1994)", Child Health and Developmental
Media, Inc., 5632 Van Nuys Blvd., Suite 286, Van Nuys, CA 91401
4. "Cortical Visual Impairment
in Children"; Good, W; Jan, J.E.; Luis, D. (1994) Survey of Ophthalmology.
Julie Bernas-Pierce, Editor
Barb Lee Dr.
Dr. William Good
Off to a Good Start Program
The Pediatric Visual Diagnosis Fact Sheets are sponsored by a grant
from the Blind Children's Center and with support from the Hilton/Perkins
Program through a grant from the Conrad Hilton Foundation of Reno, Nevada.
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