Objective perimetry using a four-channel multifocal VEP system: correlation with conventional perimetry and thickness of the retinal nerve fibre layer
- Correspondence to Folkert Horn, Department of Ophthalmology and University Eye Hospital, Friedrich-Alexander University of Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany;
Contributors All authors: (1) conceived and designed the study or analysed and interpreted the data; (2) wrote the manuscript or provided critical revisions that are important for the intellectual content; and (3) approved the final version of the manuscript.
- Accepted 2 November 2011
- Published Online First 24 November 2011
Purpose There is evidence that multifocal visual evoked potentials (VEPs) can be used as an objective tool to detect visual field loss. The aim of this study was to correlate multifocal VEP amplitudes with standard perimetry data and retinal nerve fibre layer (RNFL) thickness.
Method Multifocal VEP recordings were performed with a four-channel electrode array using 58 stimulus fields (pattern reversal dartboard). For each field, the recording from the channel with maximal signal-to-noise ratio (SNR) was retained, resulting in an SNR optimised virtual recording. Correlation with RNFL thickness, measured with spectral domain optical coherence tomography and with standard perimetry, was performed for nerve fibre bundle related areas.
Results The mean amplitudes in nerve fibre related areas were smaller in glaucoma patients than in normal subjects. The differences between both groups were most significant in mid-peripheral areas. Amplitudes in these areas were significantly correlated with corresponding RNFL thickness (Spearman R=0.76) and with standard perimetry (R=0.71).
Conclusion The multifocal VEP amplitude was correlated with perimetric visual field data and the RNFL thickness of the corresponding regions. This method of SNR optimisation is useful for extracting data from recordings and may be appropriate for objective assessment of visual function at different locations.
- objective perimetry
- retinal nerve fibre layer thickness
- diagnostic tests/investigation
- visual pathway
- field of vision
- optic nerve
- aqueous humour
- colour vision
- visual perception
Funding This work was supported by the German Research Council (SFB539).
Competing interests None.
Ethics approval The study was approved by the Local Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.