Frequency Domain Electroretinography in Retinitis Pigmentosa versus Normal Eyes.
OBJECTIVE
To compare electroretinogram (ERG) characteristics in patients with retinitis pigmentosa (RP) and normal subjects using frequency domain analysis.


METHODS
Five basic ERG recordings were performed in normal subjects and patients with a clinical diagnosis of RP according to the ISCEV (International Society of Clinical Electrophysiology of Vision) protocol. Frequency domain analysis was performed by MATLAB software. Different frequency domain parameters were compared between the study groups.


RESULTS
Peak frequency (Fmod) of flicker and oscillatory responses in RP patients showed significant (P<0.0001) high pass response as compared to normal controls. Peak frequency (Fmod) of the other responses was not significantly different between the two groups.


CONCLUSIONS
In addition to conventional ERG using time domain methods, frequency domain analysis may be useful for diagnosis of RP. Oscillatory and flicker responses may be analyzed in frequency domain. Fast Fourier transform may reveal two distinct high pass responses (shift to higher frequencies) in Fmod. Time and frequency domain analyses may be performed simultaneously with many modern ERG machines and may therefore be recommended in RP patients.
Department of Medical Physics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Homa
H
Hassan-Karimi
Ebrahim
E
Jafarzadehpur
Bahram
B
Blouri
Hassan
H
Hashemi
Arash Zare
AZ
Sadeghi
Ali
A
Mirzajani