"On" response dysfunction in multifocal posterior pigment epitheliopathy

To determine the electroretinographic properties of one patient with multifocal posterior pigment epitheliopathy. Rod and cone electroretinograms (ERGs) and photopic ERGs elicited by long-duration stimuli were studied in a patient with multifocal posterior pigment epitheliopathy. The amplitudes of both the rod and cone ERGs were significantly reduced. Photopic ERGs elicited by long-duration stimuli demonstrated that the b-wave ("on" response) was abolished but the d-wave ("off" response) was reduced by only amplitude. The ERG findings in multifocal posterior pigment epitheliopathy indicate that there is dysfunction not only of the photoreceptors but also in the signal transmission specific for the "on" pathway.