Evaluation of electrochemically treated bulk electrodes for a retinal prosthesis by examination of retinal intrinsic signals in cats
Evaluation of electrochemically treated bulk electrodes for a retinal prosthesis by examination of retinal intrinsic signals in cats
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通过检查猫的视网膜固有信号来评估用于视网膜假体的电化学处理的散装电极
DOI：
10.1007/s10384-014-0319-3
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发表时间：
2015
期刊：
影响因子：
2.4
通讯作者：
Fujikado T.
中科院分区：
文献类型：
--
作者：
Kanda H;Mihashi T;Miyoshi T;Hirohara Y;Morimoto T;Terasawa Y;Fujikado T.
目的我们的目标是确定使用电化学处理的具有大电荷注入能力的体铂电极用于视网膜假体的可行性。方法对七只猫的七只眼睛进行了研究。使用放置在巩膜袋中的经过电化学处理的大块电极（φ= 500 µm）对较小的视网膜区域进行局部刺激。记录近红外（800-880 nm）光的眼底图像，并通过从刺激后拍摄的图像中减去刺激前拍摄的图像来构建电流引起的反射率变化的二维图。每个电极的阻抗均在 1 kHz 下测量。通过光学相干断层扫描测量电极引起的视网膜抬高程度。在组织学切片中测量插入电极阵列的巩膜厚度。结果反射率变化的直径（半峰全宽）短轴为 0.42 ± 0.22 mm [平均值 ± 标准差 (SD)]，长轴为 1.46 ± 0.82 mm。阈值电流随着残余巩膜厚度的减小而减小（R2=0.9215；P=0.0002）；它也随着视网膜高度的增加而降低（R2= 0.6259；P= 0.0111）。阈值电流也随着电极阻抗的增加而降低（R2= 0.2554；P= 0.0147）。结论经过电化学处理的多孔铂电极可以刺激局部视网膜区域。刺激视网膜所需的阈值电流受到残余巩膜厚度和电极与巩膜贴合紧密度的影响。
PurposeOur goal was to determine the feasibility of using electrochemically treated bulk platinum electrodes with large charge injection capacity for a retinal prosthesis.MethodsSeven eyes of seven cats were studied. Small retinal areas were focally stimulated with electrochemically treated bulk electrodes (φ= 500 µm) placed in a scleral pocket. Fundus images with near-infrared (800–880 nm) light were recorded, and a 2D map of the reflectance changes elicited by the electrical currents was constructed by subtracting the images taken before stimulation from those taken after stimulation. The impedance of each electrode was measured at 1 kHz. The degree of retinal elevation by the electrode was measured by optical coherence tomography. Scleral thickness where the electrode array was inserted was measured in histologic sections.ResultsThe diameter of reflectance changes (full width at half maximum) was 0.42 ± 0.22 mm [mean ± standard deviation (SD)] in minor axes and 1.46 ± 0.82 mm in major axes. The threshold current decreased with a reduction in the residual scleral thickness (R2= 0.9215;P= 0.0002); it also decreased with an increase in retinal elevation (R2= 0.6259;P= 0.0111).The threshold current also decreased with an increase in electrode impedance (R2= 0.2554;P= 0.0147).ConclusionsElectrochemically treated porous platinum electrodes can stimulate localized retinal areas. The threshold current necessary to stimulate the retina was influenced by residual scleral thickness and the electrode tightness of fit against the sclera.