Fig 1.
The schematic diagram of mfERG setup for experiment 1 and 2.
The spatial frequency (SFs) gratings were presented on a 22-inch LCD display. The global flash mfERG stimulation was driven by VERIS Science 6.0.6d19. The mfERG signal was amplified X 100,000 with a bandpass of 10–300 Hz.
Fig 2.
Spatial frequency stimuli presented to subjects 1 for mfERG.
Spatial frequencies of 0.24, 1.2, 2.4 and 4.8 cycle per cpd was presented. Only ring 1 to 3 were shown in the figure.
Fig 3.
Schematic diagram for grouping the mfERG responses and the waveform of MOFO mfERG.
Left: Both DC and IC responses were pooled into concentric rings with eccentricity from ring 1 (0°) to ring 6 (19.20°)Right: Schematic diagram for DC amplitude and implicit time, IC amplitude and implicit time of global flash mfERG.
Fig 4.
The global flash mfERG response to spatial frequency.
(A) The typical global flash mfERG waveform measured from one subject with 4 spatial frequencies grating for six different retinal regions. (B) Normalized amplitudes of DC and IC response to spatial frequency of all subjects. The normalized amplitudes of DC and IC were achieved by dividing the amplitudes by the maximum value in each ring.
Fig 5.
Absolute amplitudes of DC (mean ± SEM) with SF of 0.24cpd to 4.8cpd of ring 1 to 6. The DC responses were generally increased with SF in all regions. Those marked with an asterisk ‘‘*” are statistically different from the 0.24cpd.
Fig 6.
Absolute amplitudes of IC (mean ± SEM) with SF of 0.24cpd to 4.8cpd of ring 1 to 6. In ring 1 and 2, the IC responses were similar. While from ring 3 to 6, the IC responses behaved differently from the central retina. Those marked with an asterisk ‘‘*” are statistically different from the 0.24cpd while with an asterisk“#” are statistically different between 4.8cpd and 2.4cpd.
Fig 7.
The typical global flash mfERG waveform from one subject for high and low spatial frequency under defocus.
Upper panel: (A), (B) and (C) are responses from 0.24cpd under defocus of-2D, plano and +2D respectively. Lower panel: (D), (E) and (F) are response from 4.8cpd under under defocus of-2D, plano and +2D respectively.
Table 1.
Summary of amplitude (mean ± SEM) of DC and IC under different defocus conditions with 0.24cpd or 4.8cpd from ring 1 to 6.
Fig 8.
Percentage change of DC and IC with imposing defocus under 0.24cpd or 4.8cpd.
(A) Percentage change of DC amplitudes (mean ± SEM) with imposing defocus under 0.24cpd or 4.8cpd across the region. (B) Percentage change of IC amplitudes (mean ± SEM) with imposing defocus under 0.24cpd or 4.8cpd across the region. Left panel is 0.24cpd and right panel is 4.8cd. Those marked with an asterisk ‘‘*” are statistically different between +2D and -2D defocus.