ABSTRACT
The cornea of the eye is a complex tissue, with morphological and physiological characteristics in consonance with the functions it has to perform for the organism. The corneal endothelium is known to play a key role in maintaining corneal transparency. The epithelium plays somewhat different roles in helping corneal deturgescence. The osmotic permeabilities of the corneal epithelium and endothelium are important for the understanding of the basic mechanisms of water permeation across them. A model for water relations in the cornea has been put together by S. D. Klyce and S. R. Russell, which incorporates the interactions of all corneal layers in an ensemble. To return to the model for endothelial fluid transport, one key element to consider has to do with the osmolarity values to be attributed to the different compartments and layers. The chapter argues that remarks on transendothelial and transepithelial water transfers apply to particular conditions in which the layers are isolated and operating under in vitro conditions.
