Study of visual field defects in patients with epilepsy receiving Vigabatrin

Gonzalez, Pedro Antonio (2009) Study of visual field defects in patients with epilepsy receiving Vigabatrin. MD thesis, University of Glasgow.

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Vigabatrin, a GABA (γ-aminobutyric acid) agonist is a drug widely prescribed in Europe and Asia between 1989 and 1997 for drug resistant, partial epilepsy and has been associated with visual field defects. Uncertainity in the effect of Vigabatrin on vision resulted in decreased prescriptions. However, there has been poor reproducibility in previous studies due to many factors, especially poor sensitivity and specificity of tests for Vigabatrin associated visual dysfunction. The wide field multifocal electroretinogram (WF-mfERG) can objectively measure discrete areas of retinal function up to 90 degrees. The results of 204 patients with epilepsy divided into four groups are presented. A subgroup of 89 patients had repeat investigations. The patients were divided into four groups.
Group 1.The Vigabatrin group comprised patients who had been taking Vigabatrin for at least 1 year (56 patients).
Group 2. Forty nine patients who had previously taken Vigabatrin for at least 1 year but had stopped taking this treatment for at least 2 years comprised the ex-Vigabatrin group.
Group 3.The GABA group had 46 patients who used other anti-epileptic drugs (AED) with GABA action other than Vigabatrin.
Group 4. Fifty three patients who had never used an AED with GABA action including Vigabatrin made up the non-GABA group.
Surprisingly, the percentage of patients with visual field defects were high in all groups investigated (Vigabatrin group 59%, ex-Vigabatrin group 46%, GABA group 30.2% and non-GABA group 21.2%). However, abnormal bilateral WF-mfERG responses were only found in the Vigabatrin group (48%) and the ex-Vigabatrin group (22%). The study suggests that there are probably different causes of visual field abnormalities in patients with epilepsy not related to Vigabatrin.
We propose that the most sensitive and specific tests that can be used to detect visual dysfunction associated with Vigabatrin is the WF-mfERG

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: Vigabatrin, Retinal Toxicity, Electrophysiology, Multi-focal Electroretinogram, Visual Fields
Subjects: Q Science > QC Physics
R Medicine > RM Therapeutics. Pharmacology
R Medicine > RE Ophthalmology
Colleges/Schools: College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Supervisor's Name: Keating, Dr. David
Date of Award: 2009
Depositing User: Dr Pedro A Gonzalez
Unique ID: glathesis:2009-543
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 15 Jan 2009
Last Modified: 10 Dec 2012 13:19

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