LITTLE CORRELATION OF THE PATTERN ELECTRORETINOGRAM (PERG) AND VISUAL-FIELD MEASURES IN EARLY GLAUCOMA

Pattern-electroretinograms (PERG) to checkerboard reversal at 16/s. 0. 8 degrees and 15 degrees check size and visual fields (Octopus G1) wer e retrospectively analyzed in 40 eyes of 30 patients with early glauco ma. The mean visual field defect was calculated separately for the cen tral 26 degrees x 34 degrees covered by the PERG stimulus (MDc) and th e more peripheral area (MDp) surrounding the stimulus. Deeper field lo ss was correlated with a reduced pattern electroretinogram amplitude ( p < 0.01 for both MDp and MDc), indicating that the pattern electroret inogram deteriorates as glaucoma advances. If the analysis was confine d to those 18 eyes (16 patients) that had no field defect within the a rea covered by the PERG stimulus (normal MDc but abnormal MDp), 13 of these had an abnormal PERG amplitude (p < 0.001). The results suggest that the PERG can reveal impairment of ganglion cell function that is not detected by conventional perimetry.