Nanomedicine-Based Ophthalmic Drug Delivery Systems for the Treatment of Ocular Diseases

Ocular diseases affect over 2.2 billion people globally, imposing a significant socioeconomic burden, with annual productivity losses estimated at US$411 billion. Conventional drug delivery methods-topical, local injection, and systemic administration-face challenges such as low bioavailability (<5%), rapid clearance, and physiological barriers like the cornea and blood-retinal barrier (BRB). Nanomedicine offers promising solutions by enhancing drug bioavailability, prolonging release, and enabling targeted delivery. This review explores nanomedicine-based ophthalmic drug delivery systems, including organic nanomaterials (eg, liposomes, polymer micelles, dendrimers), inorganic nanomaterials (eg, metal nanoparticles, quantum dots), and biological components (eg, exosomes). These systems improve drug penetration, reduce administration frequency, and minimize toxicity, addressing conditions like dry eye disease, keratitis, glaucoma, uveitis, age-related macular degeneration (AMD), diabetic retinopathy (DR), and retinal vascular occlusion (RVO). For instance, Ocular Therapeutix (OTX)-TP, a sustained-release intracanalicular implant combining poly (ethylene glycol)-based hydrogel with travoprost-loaded poly (lactic acid) microspheres, has shown therapeutic efficacy lasting up to three months in the management of glaucoma and ocular hypertension in Phase III clinical trial. Additionally, a liposomal formulation of verteporfin, approved for the treatment of neovascular AMD, administered intravenously and activated by laser photodynamic therapy, demonstrates a durable response, with a marked reduction in treatment frequency from an average of 3.5 sessions in the first year to only 0.1 by the fifth year post-diagnosis. Despite these advantages, challenges such as manufacturing costs, potential toxicity, and limited clinical translation persist. Future advancements in nanomedicine hold potential for personalized, non-invasive ocular therapies, revolutionizing ophthalmology.