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Yoshiaki Shimada; The late foveal response component in slow flash multifocal electroretinogram: A parametric study. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4885.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the characteristics of the late foveal response component (lfrc, Kariman et al. 2016) that presents only on the fovea on the first slice of the second-order kernel (K2.1) in multifocal electroretinograms (mfERGs) obtained with a slow base rate.
mfERGs with 103 hexagonal stimulus elements were recorded under a base rate of 18.75 Hz and a net recording time of 3 min 38 seconds using bipolar contact lens electrodes from four healthy subjects. The intensity of the stimulus (Isti) was changed parametrically, i.e., 0.16, 0.33, 0.67, 1.33, 2.67, 5.33, 10.67 cds/m2. Responses on the centermost 7 hexagons (with a diameter of 3.0-4.1°) were summed into a foveal mfERG.
At Istim 0.33 cds/m2, measurable lfrc on K2.1 of foveal mfERGs was recorded initially from all subjects. The amplitude (0.5 ± 0.1 microV) was between the start (37.7 ± 5.5 ms) and the end (62.3 ± 1.3 ms) peaks. Istim 5.33 cds/m2 maximized lfrc (2.1 ± 0.4 microV between 43.7 ± 2.0 ms and 55.2 ± 3.0 ms). At the highest Istim 10.67 cds/m2, Ifrs was reduced keeping the peak times unchanged (1.7 ± 0.6 microV between 43.5 ± 0.8 ms and 55.0 ± 5.3 ms).
Although the lfrc obtained with a 18.75 Hz base-rate differed in form from the lfrc with a 75 Hz base-rate, the timing of the potential change around at 50 ms was common. Dim flashes evoked the lfrc with an early start peak and a late end peak. At high Istim values, the behavior of lfrc was nonmonotonic, saturated with 5.33 cds/m2 and then decreased with 10.67 cds/m2.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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