Multifocal Electroretinography (mfERG):
The multifocal ERG, are used in the diagnosis of ophthalmological diseases. The mfERG is a technique for assessing the local ERG from different regions of the retina. For the routine mfERG, the retina is stimulated with a pattern of hexagons. The pattern will seem to flicker randomly, but each element follows a fixed, predetermined sequence called an ‘m sequence’. By correlating the continuous ERG signal with the on or off phases of each stimulus element, the focal ERG signal associated with each element is calculated. Electrical responses from the eye are recorded with an electrode just as in conventional ERG recording, but the special nature of the stimulus and analysis produces a more detailed map of where in the central retina ERG responses are normal or abnormal. This can help distinguish among different diseases.
A Multifocal ERG being performed with DTL electrodes.
A typical Multifocal ERG results.