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Vigabatrin-associated retinal cone system dysfunction: electroretinogram and ophthalmologic findings
G L Krauss1, M A Johnson, N R Miller
1Department of Neurology, Johns Hopkins University, Baltimore, MD, USA.
Neurology
|April 1, 1998
Summary
Vigabatrin, an epilepsy drug, can cause visual disturbances like constricted fields and blurred vision due to retinal cone system dysfunction. This may be linked to the drug's effects on GABAergic amacrine cells in vulnerable patients.
Area of Science:
- Neuroscience
- Ophthalmology
- Pharmacology
Background:
- Vigabatrin is an effective antiepileptic drug that increases gamma-aminobutyric acid (GABA) in the brain.
- Recent cases of visual field constriction in patients on vigabatrin suggest potential GABA-associated retinal dysfunction.
Observation:
- Four patients on chronic vigabatrin therapy developed visual symptoms, including constricted visual fields and blurred vision.
- Electroretinograms (ERG) revealed bilateral retinal dysfunction, specifically reduced inner retinal cone response and loss of oscillatory potentials, indicating amacrine cell impairment.
Findings:
- Two patients had normal visual evoked potentials (VEP) and minimal clinical findings despite abnormal ERGs.
- Ophthalmologic examinations showed narrowed retinal arteries, surface wrinkling retinopathy, and abnormal macular reflexes in some patients.
Implications:
- Vigabatrin-associated visual disturbances are linked to retinal cone system dysfunction.
- These symptoms may arise from individual retinal vulnerability to vigabatrin's GABAergic effects.
- Further research is needed to determine the prevalence and progression of vigabatrin-related retinal changes.