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Cortical blindness in children: a study of etiology and prognosis
1Department of Pediatrics, University of Hong Kong, Queen Mary Hospital, Pokfulam.
Insights
Congenital cortical blindness often results in permanent vision loss. Acquired blindness in children can lead to poor visual outcomes, especially with neurological insults, but some recovery is possible.
Area of Science:
- Pediatric Neurology
- Ophthalmology
- Neuroscience
Background:
- Cortical blindness in children can stem from congenital or acquired causes.
- Understanding visual outcomes is crucial for prognosis and management.
- Etiology, neurophysiological tests, and imaging play roles in assessing visual prognosis.
Purpose of the Study:
- To analyze visual outcomes in children with cortical blindness.
- To correlate outcomes with etiology, electroencephalography (EEG), visual evoked potentials (VEPs), and cranial computed tomography (CT).
Main Methods:
- Retrospective analysis of 34 children with congenital or acquired cortical blindness.
- Evaluation of etiological factors, EEG findings, VEP results, and cranial CT scans.
- Assessment of visual outcomes, including recovery and residual deficits.
Main Results:
- All 7 children with congenital cortical blindness remained blind.
- 59% of children with acquired cortical blindness had poor visual outcomes.
- Poor outcomes were linked to cardiac arrest, hypoxia, seizures, hemorrhage, thrombosis, and head trauma.
- Good outcomes were observed after hypotensive episodes post-cardiac surgery.
- 12 children showed vision recovery within 2 weeks to 5 months.
- Abnormal or absent VEPs predicted poor recovery (14% normal vision).
- Abnormal EEG (focal/multifocal spikes) and cerebral atrophy on CT were poor prognostic signs.
Conclusions:
- Congenital cortical blindness has a universally poor visual prognosis.
- Acquired cortical blindness in children carries a significant risk of poor visual outcome.
- VEPs and EEG findings, particularly abnormalities, are valuable indicators of visual prognosis.
- Cranial CT findings like cerebral atrophy also suggest a poor outlook.
Abstract:
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.