Okawa Yoshitaka, Fujikado Takashi, Miyoshi Tomomitsu, Sawai Hajime, Kusaka Shunji, Mihashi Toshifumi, Hirohara Yoko, Tano Yasuo
Department of Applied Visual Science, Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan.
Invest Ophthalmol Vis Sci. 2007 Oct;48(10):4777-84. doi: 10.1167/iovs.07-0209.
To determine whether reflectance changes of the retina after electrical suprachoroidal-transretinal stimulation (STS) can be detected with a newly developed optical imaging fundus camera.
Ten eyes of 10 cats were studied. A small retinal area was focally stimulated with electric currents passing between an active electrode placed in the fenestrated sclera and a reference electrode in the vitreous. Biphasic pulses were applied for 4 seconds with a current up to 500 muA. Images of the fundus illuminated with near-infrared (800-880 nm) light were obtained every 20 msec for 26 seconds between 2 seconds before and 20 seconds after the STS. Twenty images of 20 consecutive experiments were averaged. A two-dimensional map of the reflectance changes was constructed by subtracting the images before the stimulation from those after the stimulation. STS-evoked potentials (EPs) were recorded from the optic chiasma.
Approximately 0.5 second after the onset of STS, reflectance changes were observed around the retinal locus, where the stimulating electrodes were positioned. The intensity of the reflectance changes was correlated with the intensity of the stimulus current. The area of the reflectance change increased as the current intensity increased and was correlated with the amplitude of the EPs (R(2) = 0.82).
Reflectance changes after STS were localized to the area around the electrode. The strong correlation between the area of the reflectance changes and the amplitude of the EPs suggested that the reflectance changes reflected the activity of retinal neurons elicited by electrical stimulation.
确定能否使用新开发的光学成像眼底相机检测脉络膜上腔-视网膜电刺激（STS）后视网膜的反射率变化。
对10只猫的10只眼睛进行研究。通过置于有孔巩膜的活性电极与玻璃体内的参考电极之间的电流，对视网膜的一个小区域进行局部刺激。施加双相脉冲4秒，电流高达500微安。在STS前2秒至后20秒期间，每隔20毫秒获取一次用近红外（800 - 880纳米）光照明的眼底图像，共26秒。对20次连续实验的20幅图像求平均值。通过将刺激后图像减去刺激前图像，构建反射率变化的二维图。从视交叉记录STS诱发的电位（EPs）。
STS开始后约0.5秒，在刺激电极所在的视网膜部位周围观察到反射率变化。反射率变化的强度与刺激电流强度相关。随着电流强度增加，反射率变化的面积增大，且与EPs的幅度相关（R² = 0.82）。
STS后的反射率变化局限于电极周围区域。反射率变化面积与EPs幅度之间的强相关性表明，反射率变化反映了电刺激诱发的视网膜神经元活动。
