The impact of dorsolateral prefrontal cortex stimulation on attention networks and saccadic performance in adults with amblyopia.

Amblyopia, characterized by monocular visual deficits and impaired binocularity, attention, and oculomotor control, is often considered untreatable in adulthood due to reduced neuroplasticity. Conventional therapies target children within the critical period. This study investigated transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (dlPFC) as a novel intervention to modulate attentional networks and saccadic performance in adults with amblyopia. Thirty adults (20--35 years) with unilateral amblyopia were randomized into active tDCS (anode: F3, cathode: F4; 2 mA; n = 15) or sham groups (n = 15). Participants received 10 sessions (20 min/day, 3x/week). Attentional performance (Attention Network Test - ANT) and saccadic metrics (eye-tracking: reaction time (RT), peak velocity, fixation duration) were assessed pre- and post-intervention. Active tDCS significantly improved all ANT components: alerting, orienting, and executive control, with reduced error rates and RT. Saccadic RT decreased, and fixation durations increased. Peak velocity remained unchanged. Anodal tDCS over the left dlPFC significantly enhances attentional efficiency and saccadic performance in adults with amblyopia. These findings highlight tDCS as a promising neuromodulatory tool for addressing cognitive and motor deficits in adult amblyopia, bridging a critical gap in non-invasive therapies beyond the critical period.