1. Cortical Visual Impairment
Children with CVI are those in whom visual dysfunction is caused by lesions in the posterior visual pathways and or occipital lobes and results in temporary or permanent loss of vision.
From APH website:
Definition for Medical Purposes: 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 disturbance. See brain diagrams.
Definition for Educational Purposes: 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.
Note: A student whose visual functioning is reduced by a brain injury or dysfunction may be considered blind for educational purposes if visual function is equal to or less than the legal definition of ocular blindness.

2. Common Etiologies Prenatal Perinatal Acquired
Toxemia, intrauterine infection
Perinatal
Asphyxia, meningitis, encephalitis
Acquired
Tumor, trauma, cardiac arrest, seizures, shunt malfunction

3. Diagnostic Criteria Pupillary reaction is normal
Optic refractive media and fundus appear normal
Blink to threat is absent
Tracking behaviors usually absent

4. Characteristic Behaviors
Eye contact and visual communication skills are poor
Often appear uninterested in surroundings
May turn away from people and events in their environment
Photophobia often coexists with light gazing
Other identified behaviors are listed in the CVI protocol

5. Visual Functioning
Distance vision is apparent, but children may bring objects in close to block out visual clutter and chaos
Verbal and tactile cuing is helpful for some children, but may provide too much distraction for others
Fluctuations in visual functioning
Familiar objects recognized in one environment and not others
Visual attention is highly variable
Visually locates object then looks away before reaching for object
Differences in visual functioning may be due to differences in environment rather than in vision itself
Every time you change the environment, you change the visual response
Looking away before reaching behavior may indicate a need for child to process visual information before engaging in motor response
Or child may be taking advantage of visual fields, or using one eye to spot something and the other eye to identify it
Look to reach behavior may diminish as CVI is resolved
Distance vision may seem to improve as complexity becomes less of an issue for a child
Verbal and tactile cuing may be too much input for some children – try presenting materials without vocalizing for some children

6. Fluctuations in Visual Functioning
Visual functioning is influenced by:
Tiredness
Unfamiliar environments
Illness
Complex visual information
Poor lighting
Medications
Seizures
All of these things affect vision, complex visual information may have most impact
Arrange optimal sensory environment when possible

7. Color vision is a strength for children with CVI
Visual Perception
Color vision is a strength for children with CVI
Colors are more easily recognizable than shapes
Yellow and red seem to be the preferred colors

8. Visual Perception (con’t)
May only be able to attend to one object at a time
Need sufficient distance between objects to distinguish them
Attend better to objects in motion
Discrimination of foreground from background is difficult
Do not appear to see stationary objects but respond to moving objects, some children appear to see better when they are moving themselves

9. Resolution of CVI
25 to 50 percent of children with CVI recover some useful vision
First three years of life are optimal time for resolution of CVI
First two to three years after accident/trauma to the brain are optimal for recovery of vision
However, resolution can occur into the teens and beyond!
Resolution possible because of plasticity in the neurons of visual system – more plasticity in younger children

10. Assessment and Intervention Strategies
Use vestibular input to alert visual system
Insure proper seating, support and alignment
Avoid overwhelming the visual system with complex visual stimuli
Allow time for observation, assimilation and response
Assessment become the intervention
Traditional methods of enriching the visual environment may be detrimental to students with CVI because as the amount of visual stimuli increases, the ability to process stimuli decreases (also true for the verbal and tactile cuing we mentioned earlier – too much information may be so chaotic and disturbing that the child avoids vision – if process tactile or auditory input is easier, he may react to those stimuli rather than use his or her vision

11. Additional Assessment and Intervention Strategies
Illuminated toys
Toys with motion, or those that appear to have motion
Single stimulus
Colored objects and toys
Highlight aspects of toys, objects, shapes, etc. with favorite colors
Wide separation between array of objects
Books with single picture on each page
High contrast between foreground and background
Familiar toys and objects
Begin
with single stimulus and then add others as CVI resolves
Begin with familiar objects to elicit looking behavior then add variety

12. ISAVE CVI Protocol
Complete the Developmental History and Ocular Examination sections of the CVI protocol after interviewing caregivers and reviewing referral information, developmental history, and medical records.
Transfer observations from other ISAVE components to the CVI protocol, especially those from the Ecological Observations component.
Stimuli for assessment include materials suggested for use throughout ISAVE – be cautious of toys that do too many things at once
The information from the Ecological Observations protocol will be essential for CVI students since environment plays such an important role in visual functioning

13. CVI Protocol: Developmental History
Complete thorough interviews with caregivers and review of medical information
Check all markers on the protocol that are relevant for the child.
There are no pass or fail responses.

14. CVI Protocol: Ocular Examination
Gather information using reports from ophthalmologist or other eye care professional.
Check all markers on the protocol that are relevant for the child.

15. CVI Protocol: Additional Areas
Appearance
Visual Functioning,
Visual Perceptual Characteristics
Sensory Modalities
Posture and
Movement Characteristics
In each of these areas, gather information through personal observation, interviews with caregivers and other professionals. Check all markers on each protocol relevant to the child.

16. CVI Protocol: Impressions and Recommendations
Indicate your impressions and recommendations for further services and additional referrals.

17. Transfer results from the CVI component to the ISAVE Summary Protocol.
Familiarity with diagnostic criteria and behavioral characterisitcs associated with CVI will help teachers, parents, eye-care professionals, therapists and others to work together as a team to remediate and resolve CVI.