Tear fluid is essential for ocular surface homeostasis, providing not only lubrication for the cornea and conjunctiva but also containing a complex mixture of proteins, antibodies, and enzymes that reflect the immune status of both the eye and the systemic body. Therefore, analyzing tear components has emerged as a significant tool for the early diagnosis of inflammatory and immune-mediated ocular diseases, including chronic conjunctivitis, Sjögren’s syndrome, and autoimmune ocular inflammation.<br />Biochemical Composition and Significance<br />Tear fluid contains:<br />• Antibodies (IgA, IgG) indicating local or systemic immune responses.<br />• Antimicrobial enzymes (Lysozyme, Lactoferrin) that protect against bacterial and fungal infections.<br />• Inflammatory cytokines (IL-1, IL-6, TNF-α) which reflect active inflammation.<br />Clinical Applications<br />1. Sjögren’s Syndrome: Reduced lactoferrin levels combined with elevated inflammatory cytokines in tears may serve as an early biomarker before clinical dry eye manifestations appear.<br />2. Chronic Immune-Mediated Conjunctivitis: Tear cytokine and antibody profiling can help determine disease severity and monitor therapeutic response.<br />3. Therapeutic Monitoring: Tracking changes in tear composition provides a non-invasive method to assess the efficacy of topical and systemic immune-modulating treatments.<br />Tear fluid is not merely a lubricating medium for the eye; it represents a precise diagnostic window into inflammatory and immune ocular disorders. Integrating tear analysis into early diagnostic protocols can significantly enhance patient care and reduce vision-threatening complications associated with chronic ocular inflammation.<br />