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[Objective assessment of visual field defects using multifocal electroretinography]
U Kretschmann1, K Gendo, H Wilhelm
1Universitäts-Augenklinik, Abteilung für Pathophysiologie des Sehens und Neuro-Ophthalmologie, Tübingen.
Background:
Multifocal electroretinography allows simultaneous recording of 61 focal electroretinographic signals from the retina of the posterior pole. The function of the outer retinal layers can be mapped for a visual field of 30.5 degrees radius. We herein describe the topography of such potentials in patients with hemianopic and concentric visual field defects.
Subjects And Methods:
Six patients with visual field defects caused by chorioretinal and central visual pathways diseases were examined using multifocal ERG.
Results:
In 30 normal volunteers in the entire 30 degrees visual field clear signals were obtained. In the patients with visual field defects caused by retinal diseases in areas with reduced light sensitivity diminished electroretinographical activity was found. In contrast, in patients with bitemporal hemianopsia due to a chiasmal lesion no correlation between visual field and magnitude of focal ERGs was seen.
Conclusions:
In retinal disorders defects in multifocal ERG presented the similar pattern as scotomata in perimetry. The patient with visual field defects due to disturbances in the chiasma exhibited a normal ERG-topography. In patients with visual field defects multifocal ERG supported differentiation of the location of the lesion.