Humayun M S, de Juan E, Dagnelie G, Greenberg R J, Propst R H, Phillips D H
Department of Ophthalmology, Johns Hopkins University, Baltimore, MD, USA.
Arch Ophthalmol. 1996 Jan;114(1):40-6. doi: 10.1001/archopht.1996.01100130038006.
To evaluate the feasibility of bypassing damaged photoreceptors and electrically stimulating the remaining viable retinal layers to provide limited visual input to patients who are blind because of severe photoreceptor degeneration.
In the operating room with the patient under local anesthesia, focal electrical stimulation of the retinal surface with brief biphasic pulses was performed using small probes inserted through the sclera. The procedure was performed in five subjects who had little or no light perception. Three subjects had retinitis pigmentosa, one had age-related macular degeneration, and one had unspecified retinal degeneration from birth.
Stimulation elicited visual perception of a spot of light (phosphene). Subjects who previously had useful vision accurately localized the phosphenes according to the retinal area stimulated. Two subjects could track the movement of the stimulating electrode by reporting movement of the elicited phosphene, and could perceive two simultaneous phosphenes on independent stimulation with two electrodes. In a resolution test, one of the subjects with no light perception in his left eye resolved phosphenes at 1.75 degrees center-to-center distance (ie, 4/200 OS visual acuity).
Local electrical stimulation of the retinal surface in patients blind from outer retinal disease results in focal light perception that seems to arise from the stimulated area. Such findings in an acute experiment warrant further research into the possibility of prolonged retinal stimulation, improved resolution, and ultimately, an intraocular visual prosthesis.
评估绕过受损光感受器并电刺激剩余存活视网膜层，从而为因严重光感受器变性而失明的患者提供有限视觉输入的可行性。
在手术室中，患者处于局部麻醉状态，通过插入巩膜的小探头，用短暂的双相脉冲对视网膜表面进行局部电刺激。该手术在五名几乎没有或没有光感的受试者身上进行。三名受试者患有视网膜色素变性，一名患有年龄相关性黄斑变性，一名患有先天性未明确的视网膜变性。
刺激引发了光斑（光幻视）的视觉感知。以前有有用视力的受试者根据受刺激的视网膜区域准确地定位了光幻视。两名受试者能够通过报告诱发光幻视的移动来追踪刺激电极的移动，并且在使用两个电极进行独立刺激时能够感知到两个同时出现的光幻视。在分辨率测试中，一名左眼无光感的受试者能够分辨中心距为1.75度（即，视力为4/200 OS）的光幻视。
对因外层视网膜疾病而失明的患者进行视网膜表面局部电刺激会导致局灶性光感知，这种感知似乎来自受刺激区域。急性实验中的这些发现值得进一步研究长期视网膜刺激、提高分辨率以及最终研发眼内视觉假体的可能性。
