The two broad objectives of the proposed research are, 1) to further delineate the processes involved in the regulation of corneal thickness, and 2) to more fully describe the flow of aqueous humor into and out of the eye. 1) With regard to the cornea, the effect of surfactants on both the epithelium and endothelium will be examined using physiological and anatomical approaches; as the effect of hypertonic solutions on the epithelium will be determined also. The major emphasis, however, will lie in determination of the transport and passive properties of the corneal bounding membranes as a function of temperature. Some of these studies will be made in the living in vivo eye. The influence of various substances normally found in aqueous humor will be examined on corneal deturgescence rates, as well as the formation of cellular junctions during endothelial regeneration. A delineation of the relative roles of the epithelium and endothelium on corneal thickness will be made. 2) Aqueous humor dynamics will be examined using intraocular or intravenous infusion with different solutes (e.g., fluorescein and horseradish peroxidase) which can be microscopically visualized. Tissue sections will be examined after perfusion of the in vivo eye for various times to localize the tracer molecular and examine its movement in the eye. Other studies will examine the penetration into the eye of intravenous radioactive solutes, at constant plasma concentrations, at either short (up to 20 minutes) or long periods (over 8 hours) and the data will be examined using a mathematical analysis to determine permeability characteristics of the ciliary epithelium. A correlation will be made between the physiological and anatomical changes following infusion of intracarotid or intravenous hypertonic solutions. An attempt will be made to directly measure the tissue hydrostatic pressure in the ciliary processes, as well as to determine xc in the living rabbit eye.