What is a primary component of tears that helps prevent dryness?

The primary component of tears that helps prevent dryness is the lipid layer. This layer is crucial because it forms the outermost surface of the tear film, which stabilizes the tear film and prevents evaporation. The lipid layer is typically produced by the meibomian glands situated in the eyelids. A healthy lipid layer helps maintain moisture on the surface of the eyes, reducing dryness and irritation.

When the lipid layer is deficient or disrupted, tears can evaporate too quickly, leading to dry eye symptoms. Other components of tears, such as the mucosal and aqueous layers, contribute to the overall tear film, but it is the lipid layer that plays the most significant role in providing a barrier against evaporation, thus being essential for maintaining eye comfort and health.