| Namespace | MPheno.ontology | Obsolete | false |
| description | any functional anomaly of the thin acelullar fluid layer that covers the anterior surface of the mammalian eye and has a variety of constituents that are essential for the maintenance of the avascular transparent corneal epithelium; this film keeps the cornea wet, thus allowing gas exchange between the air and the epithelium, it cleans debris from the transparent surface, providing a clear optical path to the retina, and protects the ocular surface from invasion by bacteria and viruses; the tear film also provides essential metabolites such as retinol, which serves to preserve the transparent nature of the epithelium |
