Cortical blindness in children: a study of etiology and prognosis.

Thirty-four children (20 boys, 14 girls) with congenital and acquired cortical blindness were analyzed for visual outcome in relation to etiology, visual evoked potentials, electroencephalography, and cranial computed tomography. All 7 children with congenital cortical blindness remained blind on subsequent examination. Of the 27 children with acquired blindness, 16 (59%) had poor visual outcome. Poor visual outcome occurred in those with cardiac arrest, hypoxia, status epilepticus, intracranial hemorrhage, cerebral thrombosis, and head trauma. Good visual outcome occurred in children with hypotensive episodes after cardiac surgery. Of the 12 children with recovery of vision, the interval from acute loss of vision to partial or total recovery was 2 weeks to 5 months. Seven children had complete recovery of vision with no residual visual field defect. The majority of children (87%) had focal or multifocal spike-and-waves and slow sharp-wave discharges on electroencephalography. None had photic recruitment response or occipital spike-and-wave discharges. Flash visual evoked potential studies performed during acute episodes of cortical blindness documented 11 with absent response, 10 with bilateral increases in latency, and 6 with normal responses. There was no correlation between normal visual evoked potentials and a good visual outcome. Only 2 of 6 children with normal responses had normal vision. Abnormal or absent responses are more predictive of a poor recovery of vision because only 3 of 21 (14%) had normal vision on subsequent examination. Abnormal electroencephalographic findings with focal or multifocal spike-and-wave discharges or cerebral atrophy on cranial computed tomography are also poor prognostic signs.