Castillo-Astorga Raul, Del Valle-Batalla Lucia, Mariman Juan José, Plaza-Rosales Ivan, de Los Angeles Juricic Maria, Maldonado Pedro Esteban, Vogel Marlene, Fuentes-Flores Romulo
Escuela de Medicina, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Departamento de Kinesiología, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Front Hum Neurosci. 2023 Feb 3;17:1056432. doi: 10.3389/fnhum.2023.1056432. eCollection 2023.
Amblyopia is the interocular visual acuity difference of two lines or more with the best correction in both eyes. It is treated with ocular occlusion therapy, but its success depends on neuroplasticity, and thus is effective in children but not adults. Transcranial Direct Current Stimulation (tDCS) is suggested to increase neuroplasticity.
To determine if combined intervention of bilateral tDCS and ocular occlusion improves visual function in adults with amblyopia.
A double-blind randomized, controlled pilot trial was conducted in 10 volunteers with amblyopia. While applying ocular occlusion and performing a reading task, participants received bilateral tDCS ( = 5) or sham stimulation ( = 5), with the anodal tDCS electrode in the contralateral visual cortex and the cathodal in the ipsilateral visual cortex in relation to the amblyopic eye. Visual function (through visual acuity, stereopsis, and contrast sensitivity tests) and visual evoked potential (with checkerboard pattern stimuli presentation) were evaluated immediately after.
A total of 30 min after treatment with bilateral tDCS, visual acuity improved by 0.16 (± 0.025) LogMAR in the treatment group compared with no improvement (-0.02 ± 0.02) in five controls ( = 0.0079), along with a significant increase in the amplitude of visual evoked potentials of the amblyopic eye response ( = 0.0286). No significant changes were observed in stereopsis and contrast sensitivity. No volunteer reported any harm derived from the intervention.
Our study is the first to combine anodal and cathodal tDCS for the treatment of amblyopia, showing transient improved visual acuity in amblyopic adults.
弱视是指双眼最佳矫正视力相差两行或更多。通常采用眼遮盖疗法进行治疗，但其治疗效果取决于神经可塑性，因此该疗法对儿童有效，对成人则无效。经颅直流电刺激（tDCS）被认为可以增强神经可塑性。
确定双侧tDCS与眼遮盖联合干预是否能改善成人弱视患者的视觉功能。
对10名弱视志愿者进行了一项双盲随机对照试验。在进行眼遮盖并执行阅读任务时，参与者接受双侧tDCS（n = 5）或假刺激（n = 5），阳极tDCS电极置于与弱视眼相对的对侧视觉皮层，阴极置于同侧视觉皮层。之后立即评估视觉功能（通过视力、立体视和对比敏感度测试）和视觉诱发电位（采用棋盘格图案刺激呈现）。
与5名接受假刺激的对照者视力无改善（-0.02±0.02）相比，双侧tDCS治疗30分钟后，治疗组的视力提高了0.16（±0.025）LogMAR（P = 0.0079），同时弱视眼反应的视觉诱发电位幅值显著增加（P = 0.0286）。立体视和对比敏感度未观察到显著变化。没有志愿者报告该干预带来任何不良影响。
我们的研究首次将阳极和阴极tDCS联合用于治疗弱视，结果显示成人弱视患者的视力得到了短暂改善。
