Does vigabatrin treatment for infantile spasms bring visual field defects?

Vigabatrin (VGB) causes progressive and permanent bilateral visual field constriction in a high percentage (up to 40-50%) of patients. The possibility that vision loss from VGB may be more common, more severe or have more functional consequences in infants and children than in adults cannot be excluded (Lundbeck, USA 2009). Until now there has been no method to study visual fields of patients with infantile spasms (IS), because they are not co-operative because of their young age.

The aim of the present study is to see in patients treated by VGB at early infancy:
1) Whether there are any visual field defects
2) If yes, do they correlate with the a) the length of treatment, b) cumulative dose, c) the age when VGB was given
3) Are the visual field losses mild, moderate or severe

Static (Humphrey) perimetry (preferred) or kinetic (Goldmann) will be used. The patients now to be studied should have
1) Co-operative capacity (school age, 8-9 years or more)
2) Good fixation and concentration
3) Reliable visual charts as assessed by ophthalmologist.

Because co-operative patients will be only about 20% of the whole IS population, a multi-centric international study is necessary to get reliable results. The children to be studied will benefit from the visual examinations. The study will provide important information for doctors and the parents when addressing the decision to treat prospective children with steroids or VBG