Perceptual thresholds and electrode impedance in three retinal prosthesis subjects
Perceptual thresholds and electrode impedance in three retinal prosthesis subjects
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DOI：
10.1109/tnsre.2005.848687
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发表时间：
2005-06-01
影响因子：
4.9
通讯作者：
Humayun, MS
中科院分区：
文献类型：
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作者：
Mahadevappa, M;Weiland, JD;Humayun, MS
作为FDA批准的临床试验的一部分，三名因视网膜色素变性而失明的受试者被植入视网膜假体。植入物由眼外单元和眼内单元组成，眼外单元包含用于无线数据、功率和刺激电流生成的电子器件，眼内单元由硅橡胶基底内以4x 4模式排列的16个铂刺激电极组成。通过小大头钉将阵列固定在视网膜上。刺激器通过多线电缆连接到阵列，并由基于计算机的外部系统控制，该外部系统允许对每个电极进行精确控制。经过几个月的测试，从受试者的每个电极上获得了感知阈值和电极阻抗。从阵列和视网膜的光学相干断层成像确定电极与视网膜的距离。所有受试者的平均阈值范围为24-702 μ A（1 ms脉冲）。数据显示，接近视网膜在确定阈值和阻抗中起作用，但仅对于距离视网膜大于0.5 mm的电极。
Three test subjects blind from retinitis pigmentosa were implanted with retinal prostheses as part of a FDA-approved clinical trial. The implant consisted of an extraocular unit that contained electronics for wireless data, power, and generation of stimulus current, and an intraocular unit that consisted of 16 platinum stimulating electrodes arranged in a 4 x 4 pattern within a silicone rubber substrate. The array was held to the retina by a small tack. The stimulator was connected to the array by a multiwire cable and was controlled by a computer based external system that allowed precise control over each electrode. Perception thresholds and electrode impedance were obtained on each electrode from the subjects over several months of testing. The electrode distance from the retina was determined from optical coherence tomography imaging of the array and retina. Across all subjects, average thresholds ranged from 24-702 mu A (1-ms pulse). The data show that proximity to the retina played a role in determining the threshold and impedance, but only for electrodes that were greater than 0.5 mm from the retina.