The major functions of the tear film are to: (1) maintain a smooth surface for light refraction, (2) lubricate the eyelids, (3) supply the cornea with nutrients by transporting oxygen and a limited number of other nutrients to the avascular cornea, (4) provide white blood cells with access to the cornea and conjunctiva, (5) remove foreign materials from the cornea and conjunctiva, (6) defend the ocular surface from the pathogens via specific and nonspecific antibacterial substances, and (7) protect the ocular surface from free-radical insults with antioxidants such as ascorbic acid, lactoferrin, uric acid, and cysteine.
|Title of host publication||Encyclopedia of the Eye, Four-Volume Set|
|Number of pages||6|
|Publication status||Published - 2010 Jan 1|
- Dry eye
- Tear-film function
- Tear-film structure
ASJC Scopus subject areas