OCT retinal microstructure as a strong marker of vigabatrin related visual toxicity based on wide-field multifocal electrophysiology results

Author: Kaleena Michael (United Kingdom)

Co-authors: Stuart Parks, David Keating, Linda Stephen, John-Paul Leach

Purpose

To investigate if the examination of retinal microstructures and retinal nerve fibre layer (RNFL) thickness using the Optical coherence tomography (OCT) could reveal a structural cause behind the wide-field multifocal electrophysiology (WF-mfERG) results in patients exposed to vigabatrin.

Setting/Venue

Electrophysiology unit, Gartnavel General Hospital, Glasgow G12 0YN

Methods

This is a prospective study of 28 participants who have all been exposed to vigabatrin. The subjects were analysed based on their WF-mfERG results where they are grouped as ‘delayed’ (based on 2ms delay in peripheral field compared to central field), or non-delayed. All patients underwent OCT macula volume and OCT

Results

Analysis of the OCT microstructures based on volume reveal distinctive thickness difference in the inner retinal layers of those in the ‘delayed’ group (p<0.01). Further analysis of the retinal microstructures reveal persistent statistically significant difference across the outer nuclear layer (ONL)(p<0.01), ganglion cell layer(GCL) (p<0.01) and the inner plexiform (IPL) (p<0.01), but not the outer retinal layers.

Conlusions

The changes detected points towards damage in the ONL, GCL and IPL; which concurs with historical pathological reports in animal studies. Our observations are striking and could be helpful in leading the way for improved and more objective methods for monitoring of vigabatrin related visual toxicity.

Financial Disclosure

no financial disclosures.