Purpose: To analyse the parameters of frequency domain and time domain of the OPs in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).
Methods: OPs from 9 eyes of BRVO, 9 eyes of CRVO and 40 normal control eyes were tested. The frequency spectra of the OPs were derived through Fast Fourier Transform (FFT). The mean frequency spectra, the total power, the maximum magnitude, the maximum power and the dominant frequency in frequency domain of the OPs from the eyes of BRVO, CRVO and the normal control group were compared with each other. The OPs waveforms were reconstructed with the OPs frequency spectra data by counter-FFT. In time domain, the latencies, the amplitudes and the sum of the amplitudes of the four wavelets of OPs were measured and compared in the above subjects.
Results: There were no statistically significant differences in the magnitudes of frequency spectra, the total power, the maximum magnitude and the maximum power in the frequency range from 110 to 250 Hz between BRVO and normal subjects. However, in BRVO, the dominant frequency decreased significantly, the latencies of the first to the third OPs wavelet prolonged significantly, the amplitudes of the first and the second OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly. Comparing the results of CRVO with those of normal subjects, there were statistically significant decrease in the magnitudes of frequency spectra from 150 to 180 Hz, there were statistically significant decrease in the total power, the maximum magnitude, the maximum power and the dominant frequency in the frequency range from 110 to 250 Hz, the latencies of the first to the fourth OPs wavelet prolonged significantly, the amplitudes of the first to the third OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly.
Conclusion: Some parameters of OPs in frequency domain and time domain are abnormal in branch retinal vein occlusion and in central retinal vein occlusion, which is more marked in the latter.