Nutraceutical Intervention of Probiotics in Vision Science: A Systematic Review of Evolving Perspective

Probiotics are active elements of the gastrointestinal tract that, when administered in adequate quantities, confer prolonged health efficacy on host organisms by enhancing the equilibrium of their gut microbiota (GM). This GM regulates numerous aspects of human wellness and is required for sustaining metabolic equilibrium. A gut-eye axis is a bidirectional mechanism that suggests an interaction between intestinal microbiota and the eyes, which is robust to microbial cultures like ocular surface microbiota (OSM). This review integrated PubMed, Scopus, and Web of Science through a systematic approach and probed the therapeutic efficacy of the human microbiota against the gut-eye homeostasis, which enables the invasion and growth of bacteria in the ocular region, triggering inflammation and deranging regional intestinal immune stability, molecular resemblance, and the subsequent decrease of acceptability concerning ocular antigens. Immunomodulation of the microenvironment and improving the human gut microbiota (HGM) are keys to reducing infections. Probiotics with antibacterial properties, unlike microorganisms that induce eye infections, may significantly reduce infections, making them a potential alternative to antibiotics. The antibacterial activity of probiotic strains significantly reduced bacterial growth, suggesting clinical promise for some chronic neurodegenerative diseases related to commensal bacteria, particularly through immune modulation, nutritional competition, or inhibitory chemical production. Well-designed clinical experiments in future could explore the antimicrobial spectrum of each strain and how probiotics respond to different pathogens. With optimal delivery methods, an evaluator will likely pave the way for personalized probiotic intervention.