Tårfilm

Tårfilm, also known as tear film, is a complex tribological fluid that covers the surface of the eye. It is a dynamic layer composed of three distinct strata: an outer lipid layer, a middle aqueous layer, and an inner mucin layer. The primary function of tårfilm is to maintain a smooth optical surface for clear vision, protect the cornea from pathogens and desiccation, and lubricate the eyelids during blinking.

The lipid layer, secreted by the meibomian glands in the eyelids, is the outermost layer and helps to reduce evaporation of the aqueous component. The aqueous layer, produced by the lacrimal glands, constitutes the bulk of the tårfilm and provides hydration and nutrients. The mucin layer, secreted by goblet cells in the conjunctiva, is the innermost layer and adheres to the corneal surface, promoting the stable spread of the aqueous layer.

Disruptions to the composition or stability of tårfilm can lead to dry eye disease, a common condition characterized by discomfort, visual disturbances, and potential damage to the ocular surface. Factors such as age, environmental conditions, hormonal changes, and certain medical conditions can affect tårfilm production and quality. The proper maintenance of tårfilm is crucial for ocular health and comfortable vision.