Tear Film Layer

The tear film is a thin, multi-component fluid layer that covers the ocular surface (cornea and conjunctiva). It plays essential roles in protecting the eye from environmental insults, lubricating the ocular surface, maintaining a smooth refractive interface for vision, and preserving corneal and conjunctival health. Traditionally described as three distinct layers—lipid (outermost), aqueous (middle), and mucin (innermost)—current research suggests these layers are highly interactive, forming a dynamic gel-like structure rather than strictly segregated strata. Disruption or deficiency in any component can lead to dry eye disease or other ocular surface disorders.