Restoring Vision with Noninvasive Brain Stimulation: A Narrative Review

Vision impairment resulting from defects in the visual pathway was once considered irreversible. The main barrier is the limited plasticity of the visual system after the critical period. However, as our understanding of noninvasive brain stimulation (NIBS) deepens, its ability to enhance neural plasticity and regulate the neural system indicates a transformation in treatment and rehabilitation strategies. To verify the potential of NIBS in visual restoration, this review elaborates on the mechanisms underlying the immediate effects and aftereffects of NIBS with proofs from molecular, cellular, and systematic levels. The concept of neural oscillation is especially emphasized as it contributes greatly to cognition and can be interfered with by NIBS. Meanwhile, it discusses recent clinical findings on the use of NIBS, with or without visual perceptual learning, focusing on two key questions which have not been specified in previous reviews: (1) the duration of behavioral improvements, and (2) the optimal treatment period required for different visual functions and NIBS modalities. On the basis of the inconsistency in existing studies, this review is also devoted to optimizing the practical application of combining NIBS with VPL and concludes that the location, timing, and form of NIBS are crucial to achieving satisfying complementary effects.