Beneficial Effects of Natural Bioactive Compounds on Eye Health: A Narrative Review

Ocular diseases like age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma and cataracts are major causes of visual impairment all over the world and are closely linked to oxidative stress, inflammation and mitochondrial dysfunction. This narrative review critically summarizes the available evidence on how various natural bioactive compounds, such as carotenoids, polyphenols, flavonoids, omega-3 fatty acids and botanical extracts, can affect important molecular pathways associated with ocular degeneration. Their antioxidant, anti-inflammatory, anti-angiogenic and neuroprotective properties are given particular emphasis, especially regarding the Nrf2, NF-κB and VEGF signaling pathways. This review is different from past reviews that simply discuss the potential of bioactives in the general nutritional context; rather, it unfolds the disease-specific mechanisms and compound-specific molecular actions and gives special attention to recent advances in nano-delivery systems and precision nutrition strategies to increase the bioavailability and therapeutic targeting of these nutrients in the eyes. Moreover, it offers a framework for a comparison of evidence between preclinical and clinical studies, as well as identifying current translational gaps, including limited bioavailability and a lack of long-term clinical trials, and suggesting future directions such as genotype-guided nutrition and microbiome-informed interventions. In general, this review provides a mechanistic and translational overview of how dietary bioactive compounds relate to eye health and offers the perspective of their possible use in prevention and complementary treatment for vision-related diseases.