Dry Eye Disease: Pathophysiology, Clinical Classification, and Diagnostic Biomarkers

Abstract

Context: Dry eye disease (DED) is a prevalent ocular disorder with a complex, multifactorial pathogenesis. This review aims to provide an up-to-date synthesis of DED, emphasizing novel diagnostic biomarkers, advanced imaging modalities, and strategies for personalized clinical management. Evidence Acquisition: A comprehensive literature search of PubMed and Scopus was conducted, focusing on studies reporting intrinsic and extrinsic risk factors, DED classification, established diagnostic methods, and emerging molecular biomarkers. Articles were included if they provided clinically relevant insights into the assessment and management of DED. Results: DED arises from a dynamic interplay of intrinsic factors (e.g., aging, autoimmune conditions) and extrinsic influences (e.g., environmental stressors, medications) and manifests as ocular discomfort, irritation, and visual disturbance. Classification into aqueous-deficient dry eye (ATD), evaporative tear deficiency (ETD), and mixed aqueous-evaporative tear deficiency (MAED) enables targeted evaluation and therapy. Standard clinical tools, including symptom questionnaires (OSDI, SPEED) and objective tests (tear film breakup time, tear osmolarity), remain essential, whereas advanced imaging techniques (meibography, confocal microscopy) and noninvasive methods (lipid layer interferometry, tear breakup analysis) enhance diagnostic precision. Emerging molecular biomarkers further extend current diagnostic frameworks and support more precise monitoring and management of DED. Metabolomic studies highlight matrix metalloproteinase-9 (MMP-9) as a key mediator of ocular surface inflammation, providing both diagnostic and therapeutic insight. Conclusions: A thorough understanding of the multifactorial etiology, clinical heterogeneity, and emerging biomarkers of DED is essential for effective patient management. Integrating traditional assessment tools with novel imaging and molecular diagnostics provides a pathway toward precision medicine in DED, optimizing outcomes and guiding future research.