Abstract
Purpose :
In 1990 the International Society for Clinical Electrophysiology of Vision (ISCEV) published standards for clinical electroretinography. This was a minimum protocol to record five basic ERG responses. Corneal contact lens electrodes were recommended for basic full-field ERG recording. Gold foil, microconductive fiber and skin electrodes were considered less stable and were not considered acceptable. In 1999 update of ISCEV standards both gold foil and microconductive fiber electrodes were considered acceptable, whereas, skin electrodes were not. In the 2015 update of ISCEV standards skin electrodes were considered acceptable for recording the clinical ERG. The purpose of this study was to compare skin electrodes to microconductive thread electrodes in normal subjects to flicker stimulation.
Methods :
28 eyes of 14 subjects (9 female, 5 male) were studied with flicker ERG. ERGs were recorded to 28 Hz flicker stimulation using Espion e3 and ColorDome ganzfeld (Diagnosys LLC) system with DTL microconductive fiber electrodes (Diagnosys LLC) positioned at the limbal margin and with RETeval Sensor strip skin electrodes (LKC Technologies, Inc.) placed near the infraorbital ridge. ERGs were recorded to .3 - 300 Hz bandpass with a 100 msec sweep duration and 15 sweeps were averaged per trial. Two trials were then averaged together and the trough and peak of the flicker ERG were identified.
Results :
Trough to peak amplitude of the flicker ERG from DTL fiber electrode was significantly greater (mean= 124.8 µV) than from the skin electrode (mean=35.2 µV, F=112..785, p<0.0001). Of interest, the trough implicit time of flicker ERG was significantly shorter from the skin electrode (mean=12.17 msec) compared to the DTL fiber electrode (mean=12.97 msec, F=5.975, p=0.0216). This was also reflected in significantly shorter peak implicit time of the flicker ERG from the skin electrode (mean=26.22 msec) compared to the DTL fiber electrode (mean=26.84 msec, F=10.324, p=0.0035).
Conclusions :
Overall, the skin electrodes produced amplitudes that were only one-third that of DTL fiber electrode in normal subjects. Of interest is the shorter implicit time of flicker ERGs recorded with skin electrodes. This may reflect skin electrode placement is closer to the generator sites in the posterior pole of eye.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.