Cortical Visual Impairment Pediatric Visual Diagnosis Fact Sheet

Blind Babies Foundation

Originally appeared on the web site of the Blind Babies Foundation: http://www.blindbabies.org


Definition

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.

Cause

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.

Characteristics

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.

Behavioral/Visual Characteristics

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.

Common characteristics of visual function demonstrated by children with CVI

The behaviors of children with CVI reflect their adaptive response to the characteristics of their condition

Myths

The following statements are not true, according to current knowledge in the field:

Teaching Strategy

"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."

Resources

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. 38:4: 351-364.

Acknowledgments

Julie Bernas-Pierce, Editor
Janice Polizzi
Colette Altmann
Barb Lee
Dr. Creig Hoyt

Home Counselors

Dennak Murphy
Dr. William Good
Ann Silverrain
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.

Reproduction for resale is strictly prohibited (1/98 BBF)



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