What is the function of tear film?

The function of tear film is primarily to keep the eye moist and protect against infection. The tear film is composed of three layers: the lipid layer, the aqueous layer, and the mucin layer. These layers work together to maintain moisture on the surface of the eye, which is essential for comfort and clear vision. Moisture from the tear film prevents dryness and irritation, which can occur if the eyes do not have adequate lubrication.

Additionally, the tear film contains antimicrobial properties and enzymes that help to protect the eye from infections. By serving as a barrier, it reduces the risk of pathogens entering the eye, which is crucial for maintaining ocular health.

While the other options mention important functions related to vision, they do not accurately represent the primary role of the tear film. For example, tear film does not have a direct impact on color vision, night vision, or nutrient provision to the cornea, though it is essential for overall visual comfort and health.