Cortical/Cerebral Visual Impairment
Is it one or several or entities?
Can it co-exist with ocular impairments?
SESSION ONE
Barry S. Kran, OD, FAAO
Darick W. Wright, MA, COMS, CLVT
D. Luisa Mayer, PhD. MEd
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Webinar Objectives
 Increase understanding of the diversity of signs
and symptoms of vision impairment secondary to
pediatric brain damage/maldevelopment
 Understand the difference between brain-related
or non-brain related classifications of vision loss
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What is What?
“What about a premie with some ROP, but
not blinding, and maybe a little brain injury
but not a devastated brain?”
“Some TVI’s say it is really important for
them to know if a child’s poor vision is due
to the brain or the eye (retina) because
they would teach them differently”
Comment by Pediatric Ophthalmologist
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Brain Development
From 24 wks to term, each
cortical neuron establishes
~1000 synaptic connections
– In the last trimester,
several hundred million
synapses are created
every minute!
http://library.thinkquest.org/C001501/brain/braindevelopment.htm
Accessed 07/09/2010
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Wyatt JS. Mechanisms of brain injury in the newborn. Eye (2007)12, 1261-63
Pediatric Brain Damage and
Visual Impairment
Preterm brain injury
• Focal & generalized
white matter
abnormalities (PVL)
–
–
Impaired cortical folding,
reduced grey and white
matter volumes
Reduced growth and
development of posterior
corpus callosum and its
connections
http://neonatology.ucsf.edu/specialized-care/cerebral-palsy.aspx
Accessed 9 July 2010
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Pediatric Brain Damage and
Visual Impairment
Preterm infants are at risk for:
–
–
–
–
–
–
–
http://www.nytimes.com/imagepages/2007/08/01/health/adam/
18117Grayandwhitematterofthebrain.html Accessed 11 July 2010
Cerebral palsy
Poor gross & fine motor skills
Poor adaptive functioning
Lower intelligence quotient
Behavioral & emotional problems
Asthma
Visual pathway abnormalities
(e.g.; ROP, myopia, strabismus)
– Cortical/Cerebral VI
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O’Connor AR, Wilson CM, Fielder AR. Ophthalmological Problems associated with premature birth. Eye (2007)21, 1245-60
Pediatric Brain Damage and
Visual Impairment
Brain injury at Full term is different than injury at Preterm
Hypoxic ischemic
encephalopathy
(HIE)
– Diffuse brain damage
•
cerebral cortex,
thalamus and brainstem
– Problems with motor
control, cognition,
emotions, learning
http://neonatology.ucsf.edu/specialized-care/cerebral-palsy.aspx
Accessed 9 July 2010
– Cortical/Cerebral VI
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Primary Visual Pathway
Ocular structures
Optic tracts to the
LGN and on to
the primary
visual cortex
http://www.nature.com/nrn/journal/v6/n3/images/nrn1630-f4.jpg
Accessed 11 July 2010
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Classification of Vision Loss
• Ocular
– Eye structures, to chiasm
• Ocular motor
– Brain stem, basal ganglia, thalamus,
cerebellum
• Cortical
– Primary pathway (post-chiasm to occipital)
• Cerebral
– Post-occipital, complex brain processing areas
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CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Motor
Brain stem,
cerebellum
Ocular
Ocular media, retina,
optic nerve, to chiasm
Cerebral
Cortical
post-V1
post-chiasm to V1
(striate or occipital)
(parietal, temporal lobes,
motor cortices & frontal lobes)
DL Mayer
2.28.10
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Ocular Vision Impairment
Pre-chiasmal visual pathway
Eyes, retina, optic nerves
– Significant uncorrected refractive
Chiasm
–
–
–
–
error
Media opacities (ie. cataracts)
Retinal lesions
Retinal degeneration/dystrophy
Optic nerve damage
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Ocular Vision Impairment
Diagnostic examples:
– Retinopathy of prematurity* (retinal +)
– Achromatopsia (retinal)
– Leber congenital amaurosis (retinal)
– Albinism (macular hypoplasia and reduced ON
fibers crossing at chiasm)
– Optic nerve hypoplasia*
*Brain related visual difficulties may co-occur
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CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Motor
Brain stem,
cerebellum
Ocular
Ocular media, retina,
optic nerve, to chiasm
Cortical
post-chiasm to V1
(striate or occipital)
Cerebral
post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
DL Mayer
2.28.1013
Ocular Motor Vision Impairment
May need to be differentiated from visual
field loss, or CVI
Nystagmus
– “Nulling” head-eye positions
– Convergence null
Ocular Motor Apraxia (OMA)
– Lack of horizontal saccades
– Head thrusts to move eyes to target,
overshoot and correction to fixate
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CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Motor
Brain stem,
cerebellum
Ocular
Ocular media, retina,
optic nerve, to chiasm
Cortical
post-chiasm to V1
(striate or occipital)
Cerebral
post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
DL Mayer
2.28.1015
Cerebrum
16
http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cerebrum
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http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cortical Visual Impairment
Characteristics
• Post chiasmal to occipital lobe damage
– Light gazing or withdrawal
– Better visual attention for:
• Moving vs. static objects
• Familiar vs. novel objects
• Simple vs. complex environments
–
–
–
–
Difficulty integrating gaze with reach
Difficulty integrating looking with listening
Poor social gaze
Delayed visual (& other) responses
• Dr. Christine Roman-Lantzy
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CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Motor
Ocular
Brain stem,
cerebellum
Ocular media, retina,
optic nerve, to chiasm
Cortical
post-chiasm to V1
(striate or occipital)
Cerebral
post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
DL Mayer
2.28.1019
Cerebrum
20
http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cerebral Visual Impairment
Characteristics
• Post occipital lobe brain damage
– Complex brain processing difficulties
– Dorsal/ventral stream dysfunctions
• Prof. Gordon Dutton
• Dr. August Colenbrander calls “Cognitive
dysfunction”
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Dorsal & Ventral “pathways”
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Ventral Stream
Occipital Lobe
Temporal Lobe
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Apple!
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Ventral Stream –
“What is it?”
Recognition of objects
Occipital lobes
– Receive visual input (primary visual pathway)
Temporal lobes – input from occipital lobes
–
–
–
–
Visual “library”
Words, numbers, shapes, landmarks
Faces
Color
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Dorsal Stream
Motor Cortex
Posterior Parietal
Frontal Cortex
Occipital Lobe
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Dorsal stream
-“Where is it?”
Vision for action - visual attention,
visually guided movement
• Occipital - posterior parietal lobes
– Integration of sensory input with attention and
during motor output, management of visual
complexity
• Feedback from frontal cortices
– Motor planning, head/eye movement, visual
guidance of movement
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????
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Reach
Attend, Attend
Fixate with
Eyes
I want it
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Reach with
right hand
It’s in front of me
I want it
Apple!
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How do I move?
Where do I
look???
Too Much
Information!
!!!!!!!!
?????
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G N Dutton 2012
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Summary
• Brain damage that occurs pre-term is
different than damage that occurs with fullterm babies.
• Vision Loss can be classified based on
location within the brain and visual pathway
as:
–
–
–
–
Ocular
Ocular Motor
Cortical
Cerebral
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Summary
Visual Sequelae of Pediatric Brain Damage
A complex combination of abnormal visual
behaviors due to brain damage, with
probable subcategories that CAN co-exist
with ocular & ocular-motor categories.
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Summary
• Historically, many have defined Cortical
Vision Impairment as being associated only
with the visual pathway and occipital lobe.
• Cerebral Vision Impairment involves other
portions of the brain that are required for
visual function.
– Dr. Gordon Dutton’s - impact of damage to the Dorsal and Ventral
Streams on visual function.
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Images & Resources
About Brain Injury www.waiting.com/brainanatomy.html#anchor2884157
Brain Injury Association - http://www.biasd.com/en_brain_map.html
Wikipedia - http://en.wikipedia.org/wiki/Brain
Dennison E, Hall Lueck A eds. Proceedings Summit on Cerebral/Cortical Visual
Impairment April 30, 2005 2006 AFB Press NY, NY
Dutton GN, Bax M, editors. Clinics in developmental medicine no. 186: visual
impairment in children due to damage to the brain. London: Mac Keith Press; 2010
Hoyt CS. Visual function in the brain-damaged child. Eye. 2003;17:369–84.
Kran BS, Mayer DL. Chapter 14 Vision impairment and brain damage in Taub,
Bartuccio, Maino eds Visual diagnosis and care of the patient with special needs.
Lippincott 2012
Lueck, A (2010) Cortical or Cerebral Visual Impairment in Children: A Brief
Overview. JVIB, AFB press.
Roman-Lantzy C. Cortical Visual Impairment: An approach to assessment and37
intervention 2007 AFB Press NY, NY
Cortical/Cerebral Visual Impairment
Is it one or several entities?
Can it co-exist with ocular impairments?
KranB@neco.edu
Darick.Wright@Perkins.org
MayerL@neco.edu
38