Correlation between N2 amplitude of multifocal ERGs and retinal sensitivity and retinal nerve fiber layer thickness in glaucomatous eyes.

Abstract

To determine whether there are significant correlations between the N2 amplitude of the multifocal electroretinograms (mfERGs) and the retinal sensitivity and retinal nerve fiber layer (RNFL) thickness in glaucomatous and normal eyes. Thirty-eight glaucomatous and 11 normal eyes were studied. The mfERGs were elicited by red stimuli presented on a blue background. The responses from the central five elements within a 20° stimulated area were analyzed. The retinal sensitivity was determined by Humphrey Field Analyzer and the RNFL thickness by spectral-domain optical coherence tomography. The correlations between the N2 amplitude and the retinal sensitivity and the RNFL thickness were calculated. The N2 amplitude was significantly smaller in the glaucomatous eyes than the normal eyes in all areas (P < 0.05). There was a significant correlation between the N2 amplitude and the retinal sensitivity (1/Lambert linear unit) of the HFA for the superior retina (r = 0.36, P = 0.01), for the central retina (r = 0.54, P < 0.0001), and for the inferior retina (r = 0.51, P = 0.0001). There were significant correlations between the N2 amplitude and the RNFL thicknesses in the superior retina (r = 0.49, P = 0.0003), the central retina (r = 0.79, P < 0.0001), and the inferior retina (r = 0.52, P = 0.0001) for both normal and glaucomatous eyes. These results indicate that the activity of the retinal ganglion cells contribute to the amplitude of the N2 of the mfERGs and thus can be used as an objective monitor of retinal ganglion cell function.