Pattern electroretinograms (PERGs) in response to equiluminant red-green and blue-yellow gratings as diagnostic tool to investigate retinal ganglion cell subsystem involvement

Objective: to better characterize the properties of chromatic pattern Electroretinograms (ChPERGs) and establish normative value for a set of stimuli able to elicit robust and reliable responses, suitable for clinical application in neurological disorders. Materials and methods: PERGs were recorded in response to both equiluminant red-green (R-G) and blue-yellow (B-Y) as well as luminance (Lum) contrast stimuli (yellow-black, Y-Bk), known to emphasize activity of the parvo-, konio- and magnocellular ganglion-cell subsystem respectively. Results: PERG responses could be reliably recorded either in normal observers as well in patients and signal were reproducible. Responses exhibited a typical positive-negative (P1-N1) waveform for both R-G and B-Y stimuli and had a smaller amplitude and a longer latency that Lum ones. Conclusions: these results complement previous studies aimed at characterizing the properties of ChPERGs; in addition normative data are provided for a set of stimulus characteristics suitable for the clinical routine; furthermore pathognomonic changes in main neurological diseases are reported.