Ali M. Masmali, Sultan AL-Qhtani, Talha M. Al-Gasham, Gamal A. El-Hiti, Christine Purslow, Paul J. Murphy
DOI: http://dx.doi.org/10.1016/j.clae.2014.09.007
Contact Lens and Anterior Eye, Vol. 38, Issue 1,
Published online: October 8, 2014
xThe tear film has three main functions: maintenance of ocular surface health, creation of a smooth optical surface for clear vision, and protection of the eye from foreign bodies and infection. It consists of three main layers [1–4]. The outermost layer of the tear film is the lipid layer. This layer acts to limit evaporation of the aqueous component, as well as providing lubrication for eyelid movement and a smooth optical surface [5]. The middle layer consists principally of water, which contains ions and nutrients to supply the corneal and conjunctival epithlelia, as well as immunological proteins for ocular defence against infections [6].
