Brightness as a function of current amplitude in human retinal electrical stimulation.
Brightness as a function of current amplitude in human retinal electrical stimulation.
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DOI：
10.1167/iovs.08-2897
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发表时间：
2009-11
影响因子：
4.4
通讯作者：
Fine I
中科院分区：
文献类型：
--
作者：
Greenwald SH;Horsager A;Humayun MS;Greenberg RJ;McMahon MJ;Fine I
为了最终恢复视网膜退行性疾病患者的功能视力，南加州大学/第二视力医疗产品公司长期为盲人受试者植入由16个刺激电极组成的4 × 4阵列的视网膜外假体原型。为了准确地呈现视觉场景，视觉假体必须在一定亮度范围内传递亮度信息。为了实现这一点，单个电极产生的磷光烯的亮度应与亮度适当缩放，并且相同的亮度应在整个电极阵列中产生同等亮度的磷光烯。目的是研究视亮度是如何随着电极间刺激强度的变化而变化的。正如先前的研究所述，使用这种假体装置对神经视网膜的完整细胞进行电刺激，可以可靠地引发因视网膜色素变性而失明的人类受试者的视觉感知。在这里，在长期植入的人类受试者中，使用主观亮度评级和亮度匹配程序来测量电振幅范围内的表观亮度。发现视亮度可以描述为刺激强度的幂函数。同样的模型也可以预测电极间的亮度匹配。这些结果表明，一个相对简单的模型在电极上缩放电流，可能能够在整个阵列上产生同样明亮的磷光体。
With the goal of eventually restoring functional vision in patients with retinal degenerative diseases, USC/Second Sight Medical Products, Inc. chronically implanted blind human subjects with a prototype epiretinal prosthesis consisting of a 4 × 4 array of 16 stimulating electrodes. To accurately represent a visual scene, a visual prosthesis must convey luminance information across a range of brightness levels. To achieve this, the brightness of phosphenes produced by an individual electrode should scale appropriately with luminance, and the same luminance should produce equivalently bright phosphenes across the entire electrode array. The goal was to examine how apparent brightness changes as a function of stimulation intensity across electrodes. As described in previous studies, electrical stimulation of intact cells of the neural retina using this prosthetic device reliably elicits visual percepts in human subjects blinded by retinitis pigmentosa. Here, apparent brightness for a range of electrical amplitudes was measured using both subjective magnitude rating and brightness-matching procedures in chronically implanted human subjects. It was found that apparent brightness can be described as a power function of stimulation intensity. The same model can also predict brightness matching across electrodes. These results suggest that a relatively simple model for scaling current across electrodes may be capable of producing equivalently bright phosphenes across an entire array.
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影响因子：
4.4
作者：
de Balthasar, Chloe;Patel, Sweta;Fine, Ione
通讯作者：
Fine, Ione
DOI：
10.1109/tnsre.2005.848687
发表时间：
2005-06-01
影响因子：
4.9
作者：
Mahadevappa, M;Weiland, JD;Humayun, MS
通讯作者：
Humayun, MS
影响因子：
1.8
作者：
Humayun, MS;Weiland, JD;de Juan, E
通讯作者：
de Juan, E
影响因子：
--
作者：
Santos, A;Humayun, MS;Milam, AH
通讯作者：
Milam, AH
影响因子：
4.4
作者：
Rizzo, JF;Wyatt, J;Shire, D
通讯作者：
Shire, D