Visual field examination in children with brain disorders

Abstract

The aim of this thesis is to gain more insight in the diagnostic and prognostic implications of visual field (VF) examination in children with brain disorders. Several aspects of VF examination in children with brain disorders were evaluated: All VF examinations that were performed with the BEhavioral vi­sual FIEld (BEFIE) screening test, a technique developed to measure the peripheral VF of young and neurologically impaired children, were evaluated. We found that 74% of 1788 tests could be reliably performed and results were consistent over time in 75% of children. When we compared BEFIE test results with standard conventional perimetry (SCP), a high positive predictive value and specificity of both 98% was found. We concluded that the BEFIE test is a valuable tool to detect peripheral VF defects when SCP cannot be performed in young or neurologically impaired children. The possibility to predict VF defects based on neuroimaging of the anatomy of the brain at the age of 3 months was explored in 19 infants after perinatal arterial ischemic stroke. We found that the presence or absence of a VF defect could be correctly predicted in the majority of infants by both MRI and Diffusion Tensor Im­aging (DTI) of the optic radiation (OR) in the brain. Conventional MRI seems most suitable to use in clinical practice, since DTI requires a comprehensive analysis per individual while it added little to conventional MRI assessment. An accurate follow-up with multiple VF examinations is indicated especially in children with asymmetry of the OR. VF defects found in 192 children suspected of intracranial pressure (ICP) elevation were evaluated. We found that VF defects in children with ICP elevation mainly consisted of blind spot enlargement, which had little additional value to the presence of (suspect) papilledema during fundoscopy performed earlier. We concluded that VF examination at presentation in children suspected of increased ICP does not differentiate between children with or without intracranial hypertension, but that it could provide arguments to start therapy and may help to predict final VF outcome in children with documented ICP increase. A systematic review of previous literature on the visual outcome of patients with the Sturge-Weber syndrome (SWS) and the results of a Dutch multicenter cohort are present­ed. SWS is a rare congenital disorder with angiomatous vascular malformations in the me­ninges, dermis and eye. We emphasize the risk of these patients on a combination of vision impairing disorders, such as glaucoma, a diffuse choroidal hemangioma and a leptomeningeal angioma, and recommend adequate follow-up of both visual acuity and VF in patients with SWS. The visual outcome and prevalence of compensatory mechanisms (CMs) for hemianopia are described in 45 children who underwent hemispherectomy. Several previous case-reports described an anomalous head posture (AHP) and exotropia (XT) contralateral to the side of early brain damage, as possible CM for hemianopia. We found AHP and XT in 53% and 38% respectively. We concluded that the majority of children who undergo hemispherectomy have a good visual outcome and frequently develop CMs which may optimize their functional VF.