Visual field constriction in 91 Finnish children treated with vigabatrin.
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.
Vanhatalo
Sampsa
S
Unit of Child Neurology, Hospital for Children and Adolescents, University Hospital of Helsinki, Finland. sampsa.vanhatalo@helsinki.fi
Nousiainen
Iiris
I
Eriksson
Kai
K
Rantala
Heikki
H
Vainionpää
Leena
L
Mustonen
Kirsi
K
Aärimaa
Tuula
T
Alen
Reija
R
Aine
Marjo-Riitta
MR
Byring
Roger
R
Hirvasniemi
Aune
A
Nuutila
Auli
A
Walden
Tiina
T
Ritanen-Mohammed
Ulla-Maija
UM
Karttunen-Lewandowski
Pirkko
P
Pohjola
Leena-Maria
LM
Kaksonen
Satu
S
Jurvelin
Pekka
P
Granström
Marja-Liisa
ML
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*
D000927:Anticonvulsants; D020888:Vigabatrin