Electroretinography With the RM Electrode: Normative Reference Ranges, Variation With Age, and Comparison With the Burian-Allen Electrode.

PURPOSE

The RM Electrode is a new, single-use, soft-contact lens electrode for recording the full-field electroretinogram (ffERG). Aims were (1) to define the ffERG reference ranges for the RM Electrode, with age, from healthy volunteers and (2) to compare ffERGs recorded with the RM Electrode and Burian-Allen (BA) electrode.

METHODS

The ffERGs were recorded using the International Society of Clinical Electrophysiology of Vision (ISCEV) standard, including four ISCEV extended protocols: dark-adapted red flash, photopic negative response, ON-OFF, and S-cones. Electroretinogram (ERG) parameters and recording stability, measured from the percent coefficient of variation (%CV), were compared across electrodes.

RESULTS

Participants were 40 (19 female) healthy volunteers aged 39.4 ± 15.7 years. Participants' race (white/black/Asian = 58%/20%/18%) and ethnicity (Hispanic = 10%) were congruent with the US 2020 Census. All amplitudes and implicit times followed a log-normal distribution (except photopic b-wave and ON-OFF amplitudes); most parameters varied with age. RM Electrode dark-adapted a-wave and light-adapted b-wave amplitudes were 18% (P = 0.02) and 20% (P < 0.001) larger than the BA electrode; scotopic b-wave amplitudes did not differ. The 30-Hz ERGs were more stable for the RM Electrode (median [interquartile range] %CV = 12.3% [7.6-17.6]) compared with the BA electrode (%CV = 16.7% [12.5-26.8] (P = 0.001).

CONCLUSIONS

RM Electrode parameters and interflash ERG stability were comparable to or better than those for the BA electrode.

TRANSLATIONAL RELEVANCE

The derived reference ranges for the RM Electrode allow easy adoption of this disposable contact lens electrode that mitigates possible cross-contamination between patients.