Evaluation of phosphenes elicited by extraocular stimulation in normals and by suprachoroidal-transretinal stimulation in patients with retinitis pigmentosa
Evaluation of phosphenes elicited by extraocular stimulation in normals and by suprachoroidal-transretinal stimulation in patients with retinitis pigmentosa
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DOI：
10.1007/s00417-007-0563-z
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发表时间：
2007-10-01
影响因子：
2.7
通讯作者：
Tano, Yasuo
中科院分区：
文献类型：
--
作者：
Fujikado, Takashi;Morimoto, Takeshi;Tano, Yasuo
研究背景确定诱发电光幻视的有效参数对视网膜假体的研制至关重要。方法对8例正常人进行经角膜电刺激（transcorneal electrical stimulation，TcES）诱发的瞳孔反射（pupillary reflex，PR）进行了不同频率下的测量，并与正常人进行了比较。在6名正常人中，研究了经巩膜电刺激（TsES）引起的局部光幻视与脉冲参数之间的关系。本文对两例有光感的RP患者进行了STS诱发的光幻视检查。通过选定的通道施加双相脉冲（阴极优先，持续时间：0.5或1.0 ms，频率：20 Hz）。结果TcES诱发的PR最大，频率为20 Hz。最亮的光幻视是由TsES引起的，其脉冲串为10个以上脉冲，持续时间为0.5-1.0 ms，频率为20 - 50 Hz。在RP患者中，患者1和患者2分别用0.3-0.5 mA（0.5 ms）和0.4 mA（1.0 ms）的电流引发局部光幻视。结论持续时间为0.5- 1.0ms、频率为20-50 Hz的双相脉冲串（>= 10个脉冲）可有效地诱发正常人的光幻视。有了这些参数，STS是一种可行的方法，即使在RP的晚期阶段使用视网膜假体。
Background To determine the efficient parameters to evoke electrical phosphenes is essential for the development of a retinal prosthesis. We studied the efficient parameters in normal subjects and investigated if suprachoroidal-transretinal stimulation (STS) is effective in patients with advanced retinitis pigmentosa (RP) using these efficient parameters.Methods The amplitude of pupillary reflex (PR) evoked by transcorneal electrical stimulation (TcES) was determined at different frequencies in eight normal subjects. The relationship between localized phosphenes elicited by transscleral electrical stimulation (TsES) and the pulse parameters was also examined in six normal subjects. The phosphenes evoked by STS were examined in two patients with RP with bare light perception. Biphasic pulses (cathodic first, duration: 0.5 or 1.0 ms, frequency: 20 Hz) were applied through selected channel(s). The size and shape of the phosphenes perceived by the patients were recorded.Results The maximum PR was evoked by TcES with a frequency of 20 Hz. The brightest phosphene was elicited by TsES with a pulse train of more than 10 pulses, duration of 0.5-1.0 ms and a frequency of 20 to 50 Hz. In RP patients, localized phosphenes were elicited with a current of 0.3-0.5 mA (0.5 ms) in patient 1 and 0.4 mA (1.0 ms) in patient 2. Two isolated or dumbbell-shaped phosphenes were perceived when the stimulus was delivered through two adjacent channels.Conclusion Biphasic pulse trains (>= 10 pulses) with a duration of 0.5-1.0 ms and a frequency of 20-50 Hz were efficient for evoking phosphenes by localized extraocular stimulation in normal subjects. With these parameters, STS is a feasible method to use with a retinal prosthesis even in advanced stages of RPs.