The principal objective of the present proposal is to determine whether the standing-gradient osmotic theory can explain the observed phenomenon of solute and solvent transport known to take place across the corneal endothelium and other epithelia. The precise knowledge about the mechanism of mechanisms responsible for the maintenance of the corneal transparency is of paramount importance in the eventual prevention of blindness of corneal origin. This proposal is to examine in depth the theoretical foundations of solute-solvent coupling and the resulting fluid transport across this preparation. In order to achieve this goal the velocity and concentration profiles and the tonicity of the fluid transported as the functions of parameters such as: permeability, length and width of the intercellular channel, rate of transport and its direction, and location of transport sites in the intercellular channel and junction will be obtained by computations based on: a) the standing-gradient osmotic flow model; b) the two-membrane model, and c) electro-osmotic model. In addition to these three, other theories that could explain the transport phenomenon will be critically examined. For the standing-gradient, the problem will be approached by employing the three dimensional equations of continuity for the solute and solvent movement in the intercellular channel in order to obtain the governing differential equations. The solutions for these will be pursued by two different approaches; a) Numerical analysis employing computer techniques, and b) perturbation method using a series expansion. For the two-membrane model, the conventional volume and solute flow equations will be adopted and/or modified for this problem. In the case of electroosmosis, proper equations governing the solute and solvent flows will be developed and the solutions will be obtained by either an analytical method, if possible, or by numerical procedure.