Department of Ophthalmology, University of South Florida, 13330 USF Laurel Dr, Tampa, FL, 33612, USA.
Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
Doc Ophthalmol. 2021 Apr;142(2):213-231. doi: 10.1007/s10633-020-09797-6. Epub 2020 Oct 15.
To investigate how light stimulus conditions of varying spatial sizes affect components of the flash and long-flash electroretinogram (ERG) in normal subjects.
Three stimulus conditions were generated by a Ganzfeld stimulator: a white flash on white background (WoW), a red flash on a blue background (RoB) and an L+M-cone isolating on-off (long flash) stimulus (Cone Iso). ERGs were recorded from six subjects (5 M, 1 F) with DTL electrodes to full-field (FF), 70°, 60°, 50°, 40°, 30° and 20° diameter circular stimuli. Amplitudes and peak times for a-, b-, d- and i-wave, and PhNR were examined. PhNR amplitudes were estimated in two different ways: from baseline (fB) and from preceding b-wave peak (fP).
With decreasing stimulus size, amplitudes for all ERG waveform components attenuated and peak times increased, although the effect varied across different components. An exponential fit described the relationship between amplitudes and size of stimulated retinal area well for most components and conditions (R= 0.75-0.99), except for PhNR(fB) (R= - 0.16-0.88). For peak times, an exponential decay function also fitted the data well (R= 0.81-0.97), except in a few cases where the exponential constant was too small and a linear regression function was applied instead (a-wave Cone Iso, b- and i-wave WoW). The exponential constants for RoB amplitudes (b-wave, PhNR(fB), PhNR(fP)) were larger compared to their counterparts under WoW (p < 0.05), while there was no difference between the constants for a-wave amplitudes and peak times and for PhNR peak times. The exponential constants of amplitudes vs. area under WoW and Cone Iso were remarkably similar, while under RoB PhNR(fB) showed larger constants compared to either a- or b-wave (p < 0.05).
ERG components change in a predictable way with stimulus size and spectral characteristics of the stimulus under these conditions. This predictability could allow a modified version of these sets of stimuli to be tested for clinical applicability.
研究不同空间大小的光刺激条件如何影响正常受试者的闪光和长闪光视网膜电图（ERG）的成分。
使用全视野（FF）、70°、60°、50°、40°、30°和 20°直径圆形刺激物，通过 Ganzfeld 刺激器生成三种刺激条件：白色背景上的白色闪光（WoW）、蓝色背景上的红色闪光（RoB）和 L+M-锥体开/关（长闪光）刺激（Cone Iso）。使用 DTL 电极从 6 名受试者（5 名男性，1 名女性）中记录 ERG。检查 a-、b-、d-和 i-波以及 PhNR 的幅度和峰时。PhNR 幅度以两种不同方式估计：从基线（fB）和从前面的 b-波峰（fP）。
随着刺激大小的减小，所有 ERG 波形成分的幅度都减弱，峰时增加，尽管不同成分的影响不同。除了 PhNR(fB)（R=−0.16-0.88）外，大多数成分和条件下的指数拟合都很好地描述了幅度与刺激视网膜区域大小之间的关系（R=0.75-0.99）。对于峰时，指数衰减函数也很好地拟合了数据（R=0.81-0.97），除了在少数情况下指数常数太小而应用线性回归函数的情况（Cone Iso 的 a-波、WoW 的 b-和 i-波）。RoB 幅度的指数常数（b-波、PhNR(fB)、PhNR(fP)）大于 WoW 下的对应常数（p<0.05），而 a-波幅度和峰时以及 PhNR 峰时的指数常数没有差异。WoW 和 Cone Iso 下的幅度与面积的指数常数非常相似，而 RoB 下的 PhNR(fB)与 a-或 b-波相比显示出更大的常数（p<0.05）。
在这些条件下，ERG 成分随刺激大小和刺激的光谱特征以可预测的方式变化。这种可预测性可以允许对这些刺激集的修改版本进行测试以确定其临床适用性。
