Evaluation of Electrical Performance and Properties of Electroretinography Electrodes

Abstract

The aim of this study was to evaluate and compare the electrical performance and properties of commercially available electroretinography (ERG) electrodes. Methods: A passive ionic model was used to measure impedance, noise, and potential drift in 10 types of ocular surface and skin ERG electrodes. Results: The impedance for silver-based ocular electrodes are generally lower (range, 65.35-343.3 Ω) with smaller phase angles (range, −6.41°to −33.91°) than gold-based electrodes (impedance ranged from 285.95 Ω to 2.913 kΩ, and phase angle ranged from −59.65°to −70.01°). Silver-based ocular electrodes have less noise (median line noise of 6.48 x 10 4 nV 2 /Hz) than gold-based electrodes (median line noise of 2.26 x 10 5 nV 2 /Hz). Although silver-based electrodes usually achieve a drift rate less than 5 μV/s within 15 minutes, gold-base ocular electrode cannot achieve a stable potential. The exception is the RETeval strip type of silver electrode, which had an unusual drift at 20 minutes. The noise spectral density showed no change over time indicating that noise was not dependent on the stabilization of the electrode. Conclusions: From the range of electrodes tested, lower impedance, lower capacitance, and lower noise was observed in silver-based electrodes. Stabilization of an electrode is effective against drift of the electrode potential difference but not the noise. Translational Relevance: Application of electrodes with optimized materials improve the quality of clinical electrophysiology signals and efficiency of the recording.

Structural and functional changes in the retina in Parkinson’s disease

“… 52 The RETeval device is used alongside sensor strip electrodes that are less influenced by eye movements 53 due to their placement on the lower lid but therefore also record lower amplitudes and have lower SNR than DTL electrodes. 54 Recently, optically pumped magnetometers ( Fig. 2D ) have been shown to measure corresponding magnetic activity from the retina (magnetoretinogram) without any eye or skin contact at all, showing similar results to ERG recordings with DTL electrodes.…”

“…The RETeval sensor strip electrodes (LKC Technologies, Gaithersburg, Maryland; Welch Allyn, Skaneateles Falls, New York) simultaneously measure full-field ERG and pupillary responses to light 102. The RETeval device is used alongside sensor strip electrodes that are less influenced by eye movements103 due to their placement on the lower lid but therefore also record lower amplitudes and have lower SNR (Signal to Noise Ratio) than DTL electrodes 104. Recently, optically pumped magnetometers (figure 2D) have been shown to measure corresponding magnetic activity from the retina (magnetoretinogram) without any eye or skin contact at all, showing similar results to ERG recordings with DTL electrodes 105…”

An alternative electroretinography protocol for children: a study of diagnostic agreement and accuracy relative to ISCEV standard electroretinograms

“…Whilst we present strong findings to advocate its use, our experience emphasizes several technical factors, which must be considered by those wishing to incorporate this protocol into practice. Firstly, the choice of electrode is important to optimize the signal‐to‐noise ratio; pregelled electrodes can be more easily applied and have lower impedance than cup‐based electrodes (Man, et al., 2020). Secondly, the potential confounding effect of eye position is particularly relevant for infants.…”

Novel Machine-Learning Based Framework Using Electroretinography Data for the Detection of Early-Stage Glaucoma

“…Historically, this is due to multiple barriers related to clinical ERG data acquisition, such as limitations in reproducibility, high costs of both equipment and of individual tests, long test duration and complex test administration resulting in reduced patient acceptance and compliance, and the need for highly trained experts to administer tests. With the advent of novel ERG technologies, most of these barriers related to clinical ERG data acquisition have been removed (Nakamura et al, 2016 ; Asakawa et al, 2017 ; Kato et al, 2017 ; Hobby et al, 2018 ; Liu et al, 2018 ; Man et al, 2020 ), opening up the possibility to effectively use ERG data for glaucoma diagnostics, calling the necessity for the development of novel approaches (e.g., M-L-based ones) that is capable to quickly and thoroughly analyze such data.…”