title: Visual field constriction in 91 Finnish children treated with vigabatrin.
abstract: OBJECTIVE
  To study the prevalence and features of visual field constrictions (VFCs) associated with vigabatrin (VGB) in children.
  
  
  METHODS
  A systematic collection of all children with any history of VGB treatment in fifteen Finnish neuropediatric units was performed, and children were included after being able to cooperate reliably in repeated visual field tests by Goldmann kinetic perimetry. This inclusion criterion yielded 91 children (45 boys; 46 girls) between ages 5.6 and 17.9 years. Visual field extent <70 degrees in the temporal meridian was considered abnormal VFC.
  
  
  RESULTS
  There was a notable variation in visual field extents between successive test sessions and between different individuals. VFCs <70 degrees were found in repeated test sessions in 17 (18.7%) of 91 children. There was no difference in the ages at the study, the ages at the beginning of treatment, the total duration of the treatment, general cognitive performance, or neuroradiologic findings between the patients with normal visual fields and those with VFC, but the patients with VFC had received a higher total dose of VGB. In linear regression analysis, there were statistically significant inverse correlations between the temporal extent of the visual fields and the total dose and the duration of VGB treatment. The shortest duration of VGB treatment associated with VFC was 15 months, and the lowest total dose 914 g.
  
  
  CONCLUSIONS
  Because of a wide variation in normal visual-field test results in children, the prevalence figures of VFCs are highly dependent on the definition of normality. Although our results confirm the previous findings that VFC may occur in children treated with VGB, our study points out the need to reevaluate critically any suspected VFC to avoid misdiagnosis. Nevertheless, our study suggests that the prevalence of VFC may be lower in children than in adults, and that the cumulative dose of VGB or length of VGB therapy may add to the personal predisposition for developing VFC.
authors.affiliation: Unit of Child Neurology, Hospital for Children and Adolescents, University Hospital of Helsinki, Finland. sampsa.vanhatalo@helsinki.fi
authors.forename: Sampsa
authors.initials: S
authors.lastname: Vanhatalo
authors.forename: Iiris
authors.initials: I
authors.lastname: Nousiainen
authors.forename: Kai
authors.initials: K
authors.lastname: Eriksson
authors.forename: Heikki
authors.initials: H
authors.lastname: Rantala
authors.forename: Leena
authors.initials: L
authors.lastname: Vainionpää
authors.forename: Kirsi
authors.initials: K
authors.lastname: Mustonen
authors.forename: Tuula
authors.initials: T
authors.lastname: Aärimaa
authors.forename: Reija
authors.initials: R
authors.lastname: Alen
authors.forename: Marjo-Riitta
authors.initials: MR
authors.lastname: Aine
authors.forename: Roger
authors.initials: R
authors.lastname: Byring
authors.forename: Aune
authors.initials: A
authors.lastname: Hirvasniemi
authors.forename: Auli
authors.initials: A
authors.lastname: Nuutila
authors.forename: Tiina
authors.initials: T
authors.lastname: Walden
authors.forename: Ulla-Maija
authors.initials: UM
authors.lastname: Ritanen-Mohammed
authors.forename: Pirkko
authors.initials: P
authors.lastname: Karttunen-Lewandowski
authors.forename: Leena-Maria
authors.initials: LM
authors.lastname: Pohjola
authors.forename: Satu
authors.initials: S
authors.lastname: Kaksonen
authors.forename: Pekka
authors.initials: P
authors.lastname: Jurvelin
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Granström
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004198:Disease Susceptibility; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D020888:Vigabatrin / Q000009:adverse effects* / Q000627:therapeutic use; D014786:Vision Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D058609:Visual Field Tests / Q000706:statistics & numerical data; D014794:Visual Fields / Q000187:drug effects*
chemical_list: D000927:Anticonvulsants; D020888:Vigabatrin