Topcon Research Institute, Itabashi, Japan.
Jpn J Ophthalmol. 2011 Jan;55(1):49-56. doi: 10.1007/s10384-010-0906-x. Epub 2011 Feb 18.
To compare retinal reflectance changes (RCs) elicited by transcorneal electrical stimulation (TES) to those elicited by electrical stimulation of the optic chiasma (OX).
Two eyes of two cats were studied under general anesthesia. Biphasic electrical pulses at 20 Hz were applied for 5 ms in TES, and monophasic pulses were applied for 50 μs at 100 Hz in OX stimulation. Fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s, beginning 2 s before and ending 20 s after the electrical stimulation. To improve the signal-to-noise ratio, the images of ten consecutive recordings were averaged. Two-dimensional topographic maps of the RCs were constructed by subtracting images before the stimulation from those after the stimulation. The electrically evoked potentials (EEPs) were recorded at the OX. The effect of an intravitreal injection of tetrodotoxin (TTX) on the RCs elicited by electrical stimulation was also determined.
After electrical stimulation, RCs were observed at the optic disc, retinal arteries, and retinal veins. The two-dimensional maps of the RCs elicited by both TES and OX stimulation were similar. The latency of the RCs ranged from 2.0 to 4.0 s, and the peak occurred 6 to 9 s after the onset of the ES. The intensity of the RCs was correlated with the amplitude of EEP elicited by TES stimulation. The RCs disappeared after the TTX injection in both TES and OX stimulation.
TES activates principally the retinal ganglion cells, and a change in the blood flow is initiated thereafter.
比较经角膜电刺激（TES）和视神经交叉处电刺激（OX）引起的视网膜反射变化（RCs）。
在全身麻醉下研究两只猫的两只眼睛。在 TES 中施加 20 Hz 的双相电脉冲，持续 5 ms，在 OX 刺激中施加 100 Hz 的单相脉冲，持续 50 μs。用近红外光（800-880nm）观察眼底图像，每 25ms 记录一次，共 26s，在电刺激前 2s 开始，结束后 20s 结束。为了提高信噪比，将连续十次记录的图像平均。通过从刺激后的图像中减去刺激前的图像来构建 RCs 的二维地形图。在 OX 处记录电诱发电位（EEPs）。还确定了眼内注射河豚毒素（TTX）对电刺激引起的 RCs 的影响。
电刺激后，在视盘、视网膜动脉和视网膜静脉处观察到 RCs。由 TES 和 OX 刺激引起的 RCs 的二维图谱相似。RCs 的潜伏期范围为 2.0 至 4.0s，在 ES 开始后 6 至 9s 达到峰值。RCs 的强度与 TES 刺激引起的 EEP 的振幅相关。TTX 注射后，在 TES 和 OX 刺激中 RCs 均消失。
TES 主要激活视网膜神经节细胞，随后引发血流变化。
