A drug used to treat epilepsy causes eye problems in over four out of 10 of those prescribed it, a new study has shown.
The Journal of Neurology Neurosurgery & Psychiatry has reported the findings of University of Liverpool research which has discovered the side effects of the Vigabatrin drug.
Vigabatrin was licensed in the UK in 1989 and was the first anti-epileptic drug to come on to the market since the 1970s. Although effective, the report says it has been associated with visual field defects.
The researchers from the Walton Centre for Neurology & Neurosurgery at the University tracked down almost 600 patients who were treated with Vigabatrin between 1989 and 2001.
Among the 172 patients who merited assessment, according to published guidelines, 98 (57 per cent) were tested for visual field defects even though they had no obvious symptoms.
Vision was normal in 34 (35 per cent) and abnormal in 64 (65 per cent). In 42 (43 per cent), no cause other than a history of taking Vigabatrin, could be identified.
Stroke, previous surgery, trauma and brain damage accounted for the defects seen in the other 22 patients. There was no evidence of a cumulative effect.
Men were more likely to be affected, and almost half of those tested had a visual defect associated with Vigabatrin compared with 38 per cent of the women.
Altogether 445 patients stopped taking Vigabatrin and seizure control either improved or did not change in 93 per cent, disproving the belief that stopping the drug would lead to a downturn in seizure control, the authors have said.
The authors also concluded that Vigabatrin was an effective treatment for partial seizures and infantile spasms, but it carried a high risk of visual field defects.