Measurement of the oscillatory potential of the electroretinogram in the domains of frequency and time.

The dark-adapted and light-adapted electroretinograms of 13 subjects with 23 normal eyes were analyzed by means of Fourier spectrum. The oscillatory potentials in the time domain were filtered out from the electroretinogram after a corresponding bandpass was given in the frequency domain. The coefficient of variation of total power, dominant power and dominant frequency of the isolated oscillatory potentials in the frequency domain, summed amplitudes and area of the isolated oscillatory potentials, each amplitude and implicit time of the first four major oscillatory potential wavelets in the time domain were compared. The implicit time showed the smallest coefficient of variation; summed amplitudes of OP1 to OP4 showed smaller coefficients of variation than those of the area, the amplitude of each oscillatory potential wavelet, dominant frequency and dominant and total power. The coefficient of variation of these measurement parameters in light-adapted electroretinograms was smaller than those in dark-adapted electroretinograms.