Perinatal cortical and subcortical visual loss: Mechanisms of injury and associated ophthalmologic signs

Purpose: To determine whether term and preterm injuries to the retrogeniculate visual system are associated with recognizable patterns of ophthalmologic abnormalities and whether these patterns can be attributed to cortical (gray matter) or subcortical (white matter) injury. Design: A retrospective case series. Participants: One hundred children with clinical and neuroimaging signs of perinatal posterior visual pathway injury who were examined at Arkansas Children's Hospital Eye Clinic between 1989 and 1999. Methods: We reviewed magnetic resonance images or computed tomographic scans from 50 children with cortical (predominantly or exclusively involving cortical gray matter) and 50 children with subcortical (predominantly or exclusively involving subcortical white matter) perinatal injury to the retrogeniculate visual system. Ophthalmologic abnormalities were analyzed retrospectively in each group. Main Outcome Measures: Conjugate gaze deviation, type of strabismus, abnormal eye movements, and optic disc morphology. Results: Horizontal conjugate gaze deviation, exotropia, and a normal optic disc appearance were significantly more common in cortical than in subcortical visual loss. Tonic downgaze, esotropia, and optic nerve hypoplasia (with or without coexisting pallor) were significantly more common in subcortical than in cortical visual loss. Conclusions: Perinatal cortical and subcortical visual loss produce differing profiles of ophthalmologic dysfunction. A reclassification of periventricular leukomalacia and other forms of retrogeniculate white matter injury as subcortical visual loss would increase diagnostic specificity.