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Abstract

The purpose of this study was to determine the electrophysiological changes in patients using the anti epileptic drug vigabatrin and to correlate these findings with the previously reported risk for visual field loss in these patients. In 1998 the neurologists of both involved hospitals referred all patients on vigabatrin medication for ophthalmological examination to the outpatients clinics. Of the 33 patients whom were referred to our outpatient clinics, four had to be dropped from the study because of disability to perform the examinations the remaining 29 patients were included in the study. Standard ophthalmological investigations were carried out, and contrast sensitivity, visual field (Humphrey 30-2 and Esterman or Octopus 32), colour vision (panel D15), ERG and EOG according to ISCEV standards were tested. 18 patients continued the medication and 11 stopped taking the drug during the study. Nine of the patients who stopped the drug were followed during at least half a year afterwards, this group will be described in the combined article 'Electro ophthalmic recovery after withdrawal from vigabatrin' (Graniewski and Van der Torren, this issue). The electro-ophthalmological findings in the group of 29 patients were correlated with the visual fields and the daily and cumulative dosages of vigabatrin. Of the patients, 32% showed no visual field constriction at all; from these patients 64% had EOG and/or ERG changes. Of the patients with slight to marked visual field constriction, 90% presented EOG and/or ERG changes. Significant correlation between daily dosages of vigabatrin and visual field defects was shown as well as between visual field defects and rod and cone b wave amplitude reductions. Cumulative vigabatrin dosages presented a significant correlation with EOG ratio and ERG rod b-wave amplitude. Conclusively EOG and ERG testing were found to be even an more accurate way to monitor the direct vigabatrin effect on the outer retina and is possible different from the visual field testing.

Vigabatrin-Induced Retinal Toxicity Is Partially Mediated by Signaling in Rod and Cone Photoreceptors

“…Recently, Moskowitz et al used electroretinography to identify worsening vision among pediatric patients taking the drug and concluded that ERG testing alone may be insufficient for this purpose [6]. In addition to the ERG, sweep visual evoked potential (VEP) testing has shown promise as a tool for monitoring pediatric patients taking vigabatrin [4], [7]. Nevertheless, the mechanism of the drug’s toxicity is still poorly understood, leading to a gap in our knowledge of how to prevent its vision loss side effect in patients.…”

mTOR Inhibition Mitigates Molecular and Biochemical Alterations of Vigabatrin-Induced Visual Field Toxicity in Mice

“…As many as 40% of patients taking VGB, in controlled studies, have experienced irreversible visual field loss as measured by amplitude decreases of both the photopic electroretinogram (ERG) β-wave and the 30 Hz flicker response. 1–3 Additional clinical pathologies include abnormal macular reflexes, surface wrinkling retinopathy, and narrowed retinal arteries. 1 …”

Ophthalmologic Baseline Characteristics and 2-Year Ophthalmologic Safety Profile of Pramipexole IR Compared with Ropinirole IR in Patients with Early Parkinson’s Disease

“…This 2-year study (NCT00144300) compared ophthalmologic safety of immediate-release (IR) pramipexole and ropinirole in early idiopathic PD, adapting a comprehensive ophthalmologic assessment (COA) previously developed for vigabatrin [12, 13]. …”