The phospholipids, sterols, essential fatty acids, bound lipids, unbound lipids and lipoproteins will be studied in the membranes of thin layers of fibers at the anterior and posterior surfaces of bovine, porcine and rabbit ocular lenses. These thin cellular layers control the influx and efflux of Na ion K ion and other solutes, while the bulk of the lens fibers show little resistance to ion or solute movement. The anterior layer is largely responsible for active transport through a ATPase or other pump while the posterior surface is mostly passive. The studies will be made on normal lenses, on lenses after the anterior or posterior surfaces have been exposed separately to membrane disrupting agents, on EFA deficient lenses and on cataracts. The results of the lipid analyses will be correlated with changes in lens permeability, swelling, ATPase activity and lipid metabolism.