Recent advances in cortical visual impairment

Cortical visual impairment (CVI) is the leading cause of bilateral visual impairment in children in Western countries1–3. This finding reflects better methods for identifying visual impairment due to CNS injury and also advances in perinatal care, which have increased the survival rate of children with neurological morbidity. This review will describe advances in the diagnosis and management of CVI. Central to our discussion is a definition of CVI that includes a decrease in visual acuity. New treatment and rehabilitative measures are badly needed for this disorder. We hope to stimulate interest in CVI, a disease that has become a significant public health problem. The incidence of CVI is increasing3. In a study of five Nordic countries, Rosenberg and coworkers5 noted that brain damage accounts for a growing number of cases of childhood visual impairment. They suggested that better medical care has lowered the mortality rate of children with severe medical problems. Although CVI alone is not life threatening, its associated neurological disorders may have been fatal in the past. In one study from Chile, 2.1% of children enrolled in schools for the blind, who are either visually impaired or blind, had visual diagnoses involving CVI, although this may be an underestimate6. In another study from Liverpool, Rogers7 found that CVI was the most common cause of visual impairment in children with associated neurological disorders (49% of the study population). The Oxford Register of Early Childhood Impairments8 reports the overall incidence of bilateral vision impairment at 0.14%, with 29.5% of cases due to CVI and 14.1% due to nystagmus: the second major cause of impairment in this study population. In Northern California, CVI was also found to be the leading cause of visual impairment in children under the age of 5 years9.