[Lacrimal film and the ocular surface]

Abnormalities of the ocular surface affect a large proportion of the general population. Symptoms depend on whether the lids, the corneoconjunctival surface, or the lacrimal layer are involved. The latter results from the balance of a fragile mixture of water, lipids, and mucus. Different circumstances can lead to the disruption of the lacrimal layer associated with dry-eye symptoms, eventually leading to inflammation. Alterations observed during dry-eye disease, meibomian dysfunction, allergic conjunctivitis, contact lens wear infectious conjunctivitis, or after refractive surgery are reviewed. Patient relief depends on a reliable analysis of the mechanism involved in the ocular surface disease.