Comparisons of oscillatory potentials and 30 Hz flicker electroretinograms for discriminating eyes with diabetic retinopathy from normal eyes.

Purpose: To compare the amplitudes and implicit times of the oscillatory (OPs) of the full-field electroretinograms (ERGs) to those of the 30 Hz flicker ERGs in differentiating eyes with diabetic retinopathy (DR) from normal eyes.

Study Design: Single-center observational study.

Methods: Full-field ERGs were recorded in 55 patients with Type 2 diabetes mellitus (DM) and 20 normal control subjects. The amplitudes and implicit times of the OPs and of the 30 Hz flicker ERGs were measured. Optical coherence tomography angiography (OCTA) was used to record 3×3 mm enface images of the retina from which the vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained. The receiver operating characteristic (ROC) curves were used to determine the ability of each ERG parameter to discriminate diseased eyes from normal eyes. The significance of the correlations between each ERG parameter and the VD of the SCP and DCP was determined.

Results: The area under the ROC curves (AUCs) was significantly larger for the implicit times than for the amplitudes of each ERG component (P<0.005). There were no significant differences in the AUCs between the OPs and 30 Hz flicker ERGs in differentiating eyes with DM or DR from normal eyes. The implicit time of the 30 Hz flicker ERG had the highest significant correlation coefficient with the VD of the DCP (r = - 0.31, P <0.001).

Conclusions: The OPs and 30 Hz flicker ERGs have equal ability in differentiating eyes with DR from normal eyes but with better ability for the implicit times than the amplitudes. The implicit time of the 30 Hz flicker ERG is the most sensitive parameter that is correlated with the reduction of VD among the full-field ERG components.