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C. Lawthom, J.M. Wild; Vigabatrin in Utero: Visual Assessment Using Standard and Novel Techniques . Invest. Ophthalmol. Vis. Sci. 2006;47(13):774.
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© ARVO (1962-2015); The Authors (2016-present)
Vigabatrin (VGB) is an effective antiepileptic used in over 80 countries outside of the USA as add–on therapy for adults with epilepsy of partial onset and as mono–therapy for children with West's syndrome. First reports of vigabatrin–attributed visual field loss (VAVFL) emerged in 1997. The prevalence of VAVFL is probably at least 40%. Objectively, the 30Hz flicker electroretinogram and assessment of the peri–papillary retinal nerve fibre layer (RNFL) thickness exhibit good sensitivity and specificity for VAVFL. Thus far, standard mfERG and mfVEP techniques are of uncertain diagnostic utility. The effect on the retina of in–utero exposure to VGB is equivocal: the published literature is limited to two individuals each with one child exposed in–utero. We present here the first visual investigation of an adult with VAVFL and her two children exposed in–utero.
A mother (M) (aged 40 years) with documented VAVFL and her two daughters, aged 10 (D1) and 7 years (D2) all consented to investigation. M had received VGB for 10 years; the cumulative dose of VGB was 8.03kg. She took VGB throughout pregnancy and both children were born at term with no malformations. Each daughter was exposed to a cumulative dose of VGB of 0.56kg. All received standard neuro–ophthalmic examination and were offered full–field suprathreshold static perimetry, optical coherence tomography (OCT), and multifocal ERG (mfERG) and multifocal VEP (mfVEP).
D1 and D2 both had normal visual acuities and normal fundi and exhibited normal, and reliable, fields to the Humphrey Field Analyzer Three Zone Full Field 135 Screening Test on two separate occasions. The techniques of OCT and mfERG and mfVEP proved hard to attain in both children, particularly in D2. Equivocal results were obtained, with borderline reduced RNFL thickness in D1, and borderline mfERG results.
We report the first definitively normal visual field results in children exposed to VGB in–utero, and the first sibling pair exposed in–utero. The equivocal results obtained for OCT and multifocal electrophysiology serve to highlight the difficulties in making clinical decisions based on novel techniques, and particularly as these apply to children.
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