Blood-Ocular Barrier Dysfunction in Uveitis: A Bidirectional Model Linking Pathogenesis, Clinical Monitoring, and...

Uveitis is a heterogeneous group of intraocular inflammatory diseases and an important cause of visual impairment worldwide. Although current treatments mainly target inflammation, many patients develop chronic or recurrent disease, suggesting that inflammation control alone may not fully restore intraocular homeostasis. Increasing evidence highlights the blood-ocular barrier (BOB), including the blood-retinal barrier and blood-aqueous barrier, as a key regulator of the intraocular microenvironment. This review aims to summarize the bidirectional interaction between intraocular inflammation and blood-ocular barrier dysfunction in uveitis, and to highlight the clinical significance of barrier dysfunction in disease monitoring and management. In addition, this review discusses the potential value of incorporating barrier assessment into dynamic disease evaluation and relapse-aware management strategies. Recent studies suggest that inflammation and BOB dysfunction are bidirectionally linked. Inflammatory mediators disrupt barrier integrity, while barrier breakdown facilitates immune cell infiltration and further amplifies inflammation, forming a self-reinforcing cycle that may drive disease persistence. Importantly, BOB dysfunction also has clinical implications. Findings such as aqueous flare, macular edema on optical coherence tomography, and vascular leakage on fluorescein angiography reflect barrier status and can serve as dynamic indicators for disease monitoring. Persistent abnormalities despite reduced inflammatory cell activity may indicate incomplete barrier recovery or subclinical inflammation, helping to explain discordant clinical findings and the relapse-prone nature of uveitis. Rather than viewing BOB dysfunction solely as a pathological consequence of inflammation, this review highlights the potential clinical value in disease assessment and management. Barrier-related findings may provide additional information beyond conventional inflammatory evaluation, particularly in cases where inflammatory cell activity appears controlled, but underlying barrier alteration persists. Incorporating barrier assessment into monitoring may help interpret discordant clinical findings, improve evaluation of disease control, and support a more relapse-aware management strategy in uveitis. In addition, therapeutic approaches aimed at restoring barrier integrity may provide a more comprehensive strategy for achieving sustained remission and reducing recurrence risk.