The Gut Microbiome and Ocular Health: Unravelling the Gut-Eye Axis

A new area of research termed as the “gut-eye axis” has revealed the crucial influences of gut microbiome in the ocular physiology and in the pathogenesis of various ocular conditions. This narrative review explores current evidence on how gut microbial communities and their metabolites can contribute to the onset and development of multiple ocular conditions such as age-related macular degeneration, Sjögren syndrome, uveitis, keratitis, diabetic retinopathy, glaucoma, dry eye syndrome and chalazion and the effects of diet and microbiota-directed therapies in ocular disease management and prevention. Recent studies have revealed significant alteration in the gut microbiome in individuals with ocular conditions emphasising the crucial role played by the gut eye axis in the onset and development of ocular pathologies. Mechanistically, gut dysbiosis disrupts immune homeostasis and compromises gut barrier integrity leading to endotoxemia and systemic inflammation. Current evidence suggests that a gut microbiota enriched with antioxidant bacteria such as Bacteroides and Erysipelotrichi and a microbiome-friendly diets rich in dark fish, fruits and vegetables, vitamins - A, B12, C, D and omega 3- and -6 fatty acids are associated with maintaining good ocular health and preventing diseases. Advances in gut-targeted therapeutic approaches including prebiotics, probiotics and faecal microbiota transplantation show considerable promise in restoring microbial homeostasis and improving clinical outcomes across a range of ocular diseases. However, further large-scale, multicentric longitudinal studies and advances in microbiome sequencing technologies are essential to validate these associations and refine diagnostic and therapeutic applications. A deeper understanding of the gut-eye axis provides novel insights into the crucial influences of gut microbiome in ocular physiology and pathogenesis of ocular conditions and supports the integration of nutrition and microbiome-targeted strategies to restore microbial balance and improve outcomes in ocular diseases.