New Mydriasis-Free Electroretinogram Recorded with Skin Electrodes in Healthy Subjects

Abstract

Purpose: To evaluate the reproducibility and consistency of the new mydriasis-free electroretinogram (ERG) with a skin electrode (RETeval) device, to determine the normative values of parameters, and to clarify the usefulness of pupil records to colored-light stimulus.

Methods: A total of 100 eyes of 50 healthy subjects (mean age, 21.4 years) were enrolled. The diagnostic parameters obtained by the RETeval device were examined under the following conditions. The reproducibility was determined with the coefficient of variation (CV). The consistency was examined by intraclass correlation coefficients (ICCs). The mean value and the normal range were analyzed with a 95% confidence interval as the normative values of parameters. The correlation of parameters to pupil records (area ratio, constriction ratio) and flicker ERG was also examined in the diabetic retinopathy assessment protocol.

Results: From the CV for each of the two measurements, the amplitude has a low reproducibility compared with the implicit time. Generally good consistency was obtained with both ERG parameters (ICCs = 0.48-0.92). Moderate correlations were found for the white-, red-, and blue-light stimulus in the area ratio and the constriction ratio, respectively (r = 0.44-0.62; P = 0.010-<0.0001). No correlation was observed between pupil and flicker parameters (r = 0.06-0.34; P = 0.646-0.051).

Conclusions: The RETeval device was suggested as a possible screening device to detect the visual afferent diseases by evaluating in combination with the ERG recording and the colored-light pupil response.

Figure 1

All waveforms of the 50 eyes (red line shows mean waveform).

Figure 2

Correlation between the area ratio and the constriction ratio. Moderate correlations are found for the white-light stimulus (right eye r = 0.62, P < 0.0001; left eye r = 0.46, P = 0.002), the red-light stimulus (right eye r = 0.45, P = 0.008; left eye r = 0.44, P = 0.010), and the blue-light stimulus (right eye r = 0.53, P = 0.001; left eye r = 0.48, P = 0.003).