Blood-based inflammatory biomarkers: An overlooked tool for personalizing dry eye therapy - and the potential systemic effects of eye drop inactive ingredients

Dry eye disease (DED) is traditionally diagnosed and managed using symptom scores and ocular surface tests. However, mounting evidence links serum inflammatory markers, including CXCL9/10, CCL19/20, and TNF-α, to disease severity, suggesting that a simple blood draw could soon complement conventional chairside evaluations. Meanwhile, many commonly used artificial tears still contain benzalkonium chloride and other “inactive” excipients that can enter the systemic circulation and exacerbate inflammation. This review synthesizes current evidence on blood-based DED biomarkers, highlights data regarding the systemic absorption and toxicity of ophthalmic inactive ingredients, and presents a clinical vignette in which a patient with polypharmacy intolerance experienced rapid symptom relief after switching to a preservative-free, organic eye drop. These findings support a paradigm shift toward integrating blood-based testing and excipient minimization for more personalized and biocompatible care.