IL-17 at the eye - joint interface in psoriatic disease: mechanisms, clinical correlates, and therapeutic implications.

INTRODUCTION: Psoriatic arthritis (PsA) is an immune-mediated inflammatory disease in which the IL-23/Th17/IL-17 axis contributes to musculoskeletal and extra-musculoskeletal inflammation. Ocular manifestations, particularly dry eye disease (DED), uveitis, and less frequently episcleritis and scleritis, are increasingly recognized across psoriatic disease, although their pathobiology and relationship to systemic inflammatory pathways remain incompletely defined. AREAS COVERED: This narrative review examines evidence linking IL-17 to ocular disease in psoriatic disease, with emphasis on ocular surface inflammation. We summarize ocular involvement in PsA, review mechanistic and translational data across skin, enthesis, synovium, and the lacrimal - ocular surface unit, and appraise clinical data on IL-17-pathway inhibitors, including their established musculoskeletal and cutaneous efficacy and less consistent ocular effects. EXPERT OPINION: IL-17 may contribute to ocular surface inflammation in PsA, but this remains largely inferential because direct PsA-specific ocular data are scarce. IL-17A inhibitors are effective in musculoskeletal and cutaneous disease, yet ocular benefit cannot be assumed from systemic efficacy. Current evidence suggests limited impact on established DED and less consistent uveitis protection than monoclonal TNF inhibition. Prospective studies with adjudicated ocular endpoints and tear/conjunctival profiling are needed to define whether IL-17-responsive ocular phenotypes exist in PsA.