Associations of complete blood count-derived inflammatory markers with tear film instability: a cross-sectional study.

PURPOSE: To examine whether complete blood count-derived inflammatory indices are associated with markedly shortened average non-invasive tear break-up time (NIBUT) in adults undergoing routine health examinations. METHODS: This cross-sectional study included 999 adults. Average NIBUT was calculated from three consecutive automated measurements; ≤5 s was prespecified as a markedly shortened tear-film stability phenotype, not a diagnostic criterion for dry eye disease. Six inflammatory indices were assessed in separate regression models adjusted for age, sex, body mass index, smoking, and alcohol consumption, with Benjamini-Hochberg false discovery rate correction. RESULTS: Among 999 participants, 669 (67.0%) had average NIBUT ≤5 s. In fully adjusted analyses of 996 participants, higher neutrophil-to-platelet ratio (OR, 1.34; 95% CI, 1.05-1.70; q = 0.034), systemic inflammatory response index (SIRI; OR, 1.76; 95% CI, 1.18-2.64; q = 0.018), and systemic immune-inflammation index (SII) per 100-unit increase (OR, 1.11; 95% CI, 1.04-1.19; q = 0.015) were associated with markedly shortened average NIBUT. SIRI and SII were most consistent across sensitivity analyses. Among 404 participants with Ocular Surface Disease Index data, platelet-to-lymphocyte ratio and SII were associated with an exploratory symptom-plus-sign composite outcome after false discovery rate correction; SII was the only marker significant in both analyses. CONCLUSIONS: Markedly shortened average NIBUT was associated with a systemic inflammatory context characterized most consistently by higher SIRI and SII. These findings support further investigation of systemic inflammatory profiling as a complementary phenotyping dimension in tear-film instability.