The Efficacy of Repetitive Transorbital Alternating Current Stimulation (rtACS) in Patients With Optic Nerve Damage: A Systematic Review and Meta-Analysis.

Optic nerve disorders significantly contribute to visual impairment with irreversible visual deficits. Current treatments have limited efficacy in resolving chronic visual deficits, necessitating novel therapeutic strategies. Neurorehabilitation techniques, including repetitive transorbital alternating current stimulation (rtACS), have emerged as promising approaches to restore lost visual function through the ability to modulate brain activity. However, the evidence on the effectiveness of rtACS remains inconclusive, warranting a systematic review to assess its potential as a therapeutic intervention for optic nerve-related visual deficits. This study exclusively evaluated the effectiveness of rtACS for visual field restoration in patients with optic nerve damage, including only randomized controlled trials (RCTs) that met the strict eligibility criteria. A thorough screening and data extraction process was conducted by independent reviewers, followed by a meta-analysis to assess the statistical significance and heterogeneity of the included studies. The improvement in the visual field in the rtACS compared to the sham group was the primary outcome, and visual acuity improvement was the secondary outcome. This study included three RCTs that evaluated the effects of rtACS compared to sham control in treating optic nerve damage. In regard to visual field (VF), the results revealed a significant improvement in the detection accuracy of the rtACS group compared to the control group, with a pooled mean difference of 32.06 [95% CI: 19.2, 51.2] (p=0.001, I2= 0%). The near and far vision revealed no statistically significant difference between both groups. Based on the systematic review, the use of rtACS shows a promising effect in improving the detection accuracy of the VF for patients with optic nerve damage, with a significant benefit over sham control. However, the effects on other visual outcomes were minimal, and safety data was limited. Further high-quality trials are needed to corroborate the findings and provide a more comprehensive evaluation of its efficacy and safety for treating optic nerve-related visual deficits.