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J. R. Charlier, X. Zanlonghi, C. Malbrel; Evaluation of the Spatial Frequency Response of the Pattern Erg With a Sweep Technique. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1488.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the feasibility of a sweep technique for the evaluation of the spatial frequency response of the pattern ERG.
The study was performed on 14 normal subjects and 10 patients with optic nerve disease. A checkerboard pattern covering 50 degrees of visual angle was generated at a reversing frequency of 12 Hz. 22 decrements of pattern size were performed within 11 seconds with a spatial frequency ranging from 0.15 up to 2.5 cycles per degree (cpd). The pattern ERG was recorded with skin or HK loop electrodes. The data from a minimum of 5 sweeps was vector averaged. The magnitude and phase of the 1st harmonic response were plotted as a function of spatial frequency.
In normal subjects, the maximum magnitude was obtained around 0.3 cpd and the cut-off high spatial frequency (measured as the spatial frequency corresponding to 70 percent of the maximum response amplitude) was above 2.5 cpd. Patients with optic nerve disease presented a significant reduction of the cut-off high spatial frequency.
Preliminary results indicate that the sweep technique can provide an evaluation of the spatial frequency response of the pattern ERG in about 2 minutes. The high cut-off spatial frequency might be a useful quantification parameter.
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