Uveitis and Scleritis as Early Signals of Undiagnosed IBD: A Tiered Screening Framework to Reduce Diagnostic Delay.

Uveitis and scleritis are well-recognized extraintestinal manifestations of inflammatory bowel disease (IBD). Although ocular involvement typically follows IBD diagnosis, a meaningful subset of patients presents to ophthalmologists before intestinal disease is recognized, sometimes years earlier. Despite this, no standardized ophthalmologic screening protocols exist to guide early detection. We synthesized cohort studies, meta-analyses, and Mendelian randomization evidence on the ocular-intestinal temporal relationship in IBD. Patients with uveitis or scleritis have approximately double the risk of a subsequent IBD diagnosis (adjusted HR 1.44-2.25), with median diagnostic intervals exceeding two years and often longer in pediatric populations (>5 years). Mendelian randomization studies provide genetic evidence supporting a causal effect of IBD on uveitis. In a large pediatric cohort (n = 2,555), ocular manifestations preceded IBD in approximately 20% of cases. Uveitis occurs more frequently in Crohn's disease than in ulcerative colitis, and no ophthalmology guideline provides actionable screening criteria for IBD. We propose a tiered, risk-stratified framework to identify undiagnosed IBD in ophthalmology settings: (Tier 1) universal gastrointestinal symptom screening for non-infectious or recurrent uveitis and all scleritis; (Tier 2) targeted laboratory evaluation, including fecal calprotectin in high-risk patients; and (Tier 3) low-threshold gastroenterology referral for positive screens or persistent clinical concern. Lower referral thresholds are appropriate in pediatric populations. This framework is proposed to complement clinical judgment and requires prospective validation before adoption as standard practice. By recognizing ocular inflammation as an early systemic signal, ophthalmologists are uniquely positioned to reduce diagnostic delay and improve interdisciplinary care in IBD.