The gut-eye axis in inflammatory bowel disease: shared immune mechanisms and targeted therapies

Inflammatory bowel disease (IBD) is recognized not only as a disease confined to the intestinal tract, but also as a systemic immune-mediated disorder. Among its diverse extraintestinal manifestations, ocular complications, which range from self-limiting episcleritis to severe and sight-threatening uveitis and scleritis, represent a critical clinical challenge that profoundly impacts patient quality of life. This review synthesizes the epidemiological landscape and clinical spectrum of ocular manifestations in IBD, framing their pathogenesis through the emerging concept of the gut-eye axis. We critically examine the shared mechanistic pathways driving this bidirectional relationship, including the systemic dissemination of circulating inflammatory cytokines, aberrant lymphocyte homing, cross-reactive autoantibodies, shared genetic susceptibilities, and microbiota dysbiosis, which collectively compromise the blood-ocular barrier. Furthermore, we outline targeted therapeutic strategies, highlighting that while systemic anti-TNF agents remain the cornerstone for severe and refractory ocular inflammation, gut-selective biologics like vedolizumab necessitate careful application due to the risk of extraintestinal exacerbation. Finally, we underscore the indispensable role of multidisciplinary management and highlight future research trajectories.