Performance of photovoltaic arrays in-vivo and characteristics of prosthetic vision in animals with retinal degeneration.
Performance of photovoltaic arrays in-vivo and characteristics of prosthetic vision in animals with retinal degeneration.
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DOI：
10.1016/j.visres.2014.09.007
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发表时间：
2015-06
期刊：
影响因子：
1.8
通讯作者：
Palanker, Daniel
中科院分区：
文献类型：
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作者：
Lorach, Henri;Goetz, Georges;Mandel, Yossi;Lei, Xin;Kamins, Theodore I.;Mathieson, Keith;Huie, Philip;Dalal, Roopa;Harris, James S.;Palanker, Daniel
视网膜变性过程中光感受器的丢失会导致失明，但通过对剩余的视网膜神经元进行电刺激，信息可以重新引入视觉系统。视网膜下光伏阵列将脉冲照明转换为脉冲电流，以刺激视网膜内神经元。由于所需的辐照度超过自然亮度级别，因此使用不可见的近红外光(915 Nm)来避免畏光效果。我们用不同像素大小的阵列和不同数量的光电二极管表征了对假体刺激的皮质反应的阈值和动态范围。对于具有140微米像素的设备，刺激阈值大约是70微米像素的一半，并且对于两种像素大小，使用2个二极管的阈值低于每个像素使用3个二极管的阈值。在所有情况下，这些阈值都比眼睛安全限值低两个数量级以上。在高刺激频率(>；20 Hz)下，皮质反应呈现闪烁融合。可以通过改变脉冲持续时间或辐照度来实现超过一个数量级的动态范围。然而，对比敏感度非常有限。即使只有几个照亮的像素，也可以检测到皮质反应。最后，我们证明，记录视网膜下阵列图案照明时的角膜电位可以监控每个像素产生的电流，从而评估植入物性能随时间的变化。
Loss of photoreceptors during retinal degeneration leads to blindness, but information can be reintroduced into the visual system using electrical stimulation of the remaining retinal neurons. Subretinal photovoltaic arrays convert pulsed illumination into pulsed electric current to stimulate the inner retinal neurons. Since required irradiance exceeds the natural luminance levels, an invisible near-infrared (915nm) light is used to avoid photophobic effects. We characterized the thresholds and dynamic range of cortical responses to prosthetic stimulation with arrays of various pixel sizes and with different number of photodiodes. Stimulation thresholds for devices with 140µm pixels were approximately half those of 70µm pixels, and with both pixel sizes, thresholds were lower with 2 diodes than with 3 diodes per pixel. In all cases these thresholds were more than two orders of magnitude below the ocular safety limit. At high stimulation frequencies (>20Hz), the cortical response exhibited flicker fusion. Over one order of magnitude of dynamic range could be achieved by varying either pulse duration or irradiance. However, contrast sensitivity was very limited. Cortical responses could be detected even with only a few illuminated pixels. Finally, we demonstrate that recording of the corneal electric potential in response to patterned illumination of the subretinal arrays allows monitoring the current produced by each pixel, and thereby assessing the changes in the implant performance over time.
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影响因子：
1.8
作者：
Sutter, EE
通讯作者：
Sutter, EE
影响因子：
4
作者：
Wang, Lele;Mathieson, K.;Palanker, D. V.
通讯作者：
Palanker, D. V.
DOI：
10.1109/tbcas.2011.2144980
发表时间：
2011-10-01
影响因子：
5.1
作者：
Loudin, James D.;Cogan, Stuart F.;Palanker, Daniel V.
通讯作者：
Palanker, Daniel V.
影响因子：
4
作者：
Goetz GA;Mandel Y;Manivanh R;Palanker DV;Čižmár T
通讯作者：
Čižmár T
影响因子：
16.6
作者：
通讯作者：
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