Research and application of direct current in medicine: From cellular and molecular mechanisms to clinical application in ophthalmology.

Direct current (DC) is a direction-constant current, and the research on its biological mechanism is expanding from traditional physical therapy to the field of precision medicine. This comprehensive review systematically summarizes the physical properties of DC and its core biological effects (ion migration, electroosmosis, and electrophoresis) and focuses on the cellular mechanisms and clinical applications in tissue repair and regeneration (e.g., wound healing and angiogenesis) and neurological disease treatment (e.g., modulation of neuroplasticity by transcranial DC stimulation). This review focuses on the field of ophthalmology, where DC stimulation has been shown to promote orderly corneal repair, modulate aqueous humor dynamics to reduce intraocular pressure in patients with glaucoma, and ameliorate retinal degenerative diseases and central visual dysfunction. Although DC therapy in ophthalmology has shown unique advantages, including precise targeting, minimal invasiveness, synergistic drug enhancement, and regenerative potential, its clinical translation still faces challenges in safety control, precise targeted delivery, and individualized treatment. In the future, it is necessary to promote the integration of medical and engineering fields, explore electro-drug synergistic strategies, develop intelligent closed-loop systems, and standardize clinical protocols, so as to provide new solutions to break through the bottleneck of the treatment of refractory ocular disease.