ERG Critical Flicker Frequency Assessment in Humans
Scotopic and photopic critical flicker frequency (CFF) were measured in normal subjects between the ages 20–28 and 50–58 years. Flicker electroretinograms (ERG) were recorded with stimulus frequencies from 4 to 16 Hz for scotopic intensities and 25–72 Hz for photopic intensities. ERG responses were quantified by the fast Fourier transform (FFT) magnitude. CFF was determined by fitting a line to the log-FFT-response peak vs. frequency. The slope of the older group was very similar to that of the younger group. The younger group displayed a consistent trend of higher CFF at all intensities tested.