Figure 2: Mean (±SEM) fERG functions, plotting log amplitude versus log modulation depth of the flicker stimulus, recorded from all 29 patients at baseline and at the various time points of the study. Note that mean fERG function was shifted uniformly to the left on the -axis after the first three months of supplementation and then remained stable. Arrows in the plot indicate the mean shift in fERG sensitivity observed by comparing the baseline with the follow-up fERG recordings (averaged across the different times). Asterisks indicate data points that were significantly ( ) different from baseline.