The optic nerve head component of the monkey's (Macaca mulatta) multifocal electroretinogram (mERG)

To search for an optic nerve head component (ONHC) in the monkey's (Macaca mulatta) multifocal electroretinogram (mERG), mERGs from three animals were recorded with different electrode configurations. A component with a latency that varied with distance from the optic nerve head was easily identified by eye in recordings from the speculum of a Burian-Allen electrode referenced to a DTL on the unstimulated eye. This component was reasonably well isolated by subtracting a weighted version of a Burian-Allen bipolar recording or by employing the extraction algorithm of Sutter and Bearse (1999, Vision Research, 39, 419-436). The waveform of this component resembles the ONHC reported for the human mERG.