Understanding Tear Composition and Function in Dry Eye Disease

In this segment, the expert panel discusses the clinical importance of distinguishing basal tear production from reflex tearing when evaluating patients with dry eye disease. They explain that although both types of tears share many biochemical components, basal tears contain these elements in much higher concentrations, making them essential for epithelial health, nerve function, and overall ocular surface stability. Reflex tears, by contrast, simply wet the surface temporarily and often run down the cheek—giving patients the misleading impression that their eyes “can’t be dry.” The faculty note that this distinction frequently arises in patient conversations, especially when individuals believe that tearing rules out dryness. They use relatable examples, such as tearing from cutting onions or removing debris from the eye, to illustrate that reflexive tearing does not replace true basal tear function. The panel reflects on how treatment options for dry eye have expanded significantly over time, allowing clinicians to better address deficiencies in the tear film’s protective baseline components.