Curcumin in Ophthalmology: Mechanisms, Challenges, and Emerging Opportunities.

Ocular diseases affecting the anterior and posterior segments of the eye are major causes of global vision impairment. Curcumin, a natural polyphenol, exhibits anti-inflammatory, antioxidant, antibacterial, and neuroprotective properties, making it a promising candidate for ocular therapy. However, its clinical use is hindered by low aqueous solubility, poor bioavailability, and rapid systemic elimination. This review comprehensively highlights advances in curcumin delivery systems aimed at overcoming these challenges. Emerging platforms, including proniosomal gels, transferosomes, and cyclodextrin complexes, have improved solubility, permeability, and ocular retention. Nanoparticle-based carriers, such as hybrid hydrogels and biodegradable nanoparticles, enable sustained release and targeted delivery, supporting treatments for posterior segment diseases like diabetic retinopathy and age-related macular degeneration. For anterior segment conditions, including keratitis and dry eye syndrome, cyclodextrin-based complexes and mucoadhesive systems enhance corneal permeability and drug retention. Mechanistically, curcumin modulates key pathways, such as NF-κB and TLR4, reducing oxidative stress, angiogenesis, and apoptosis. Emerging strategies like photodynamic therapy and neuroprotective approaches broaden their application to eyelid conditions and neuroinflammatory ocular diseases. These advancements address curcumin's pharmacokinetic limitations, supporting its clinical translation into ophthalmic therapies. This work underscores curcumin's potential in ocular disease management and advocates clinical trials to validate its safety, efficacy, and therapeutic relevance.