Fine structure of the normal eye tissue has been studied with a specific emphasis of dynamic functions of individual cell elements. Completed projects are: sliding of the epithelium in experimental corneal wound; corneal stroma cell; maturation of the lens cell; development of the optic nerve of the rat; structure of the muscles of the upper eyelid. Several pathological eye tissues have been studied by electron microscopy to elucidate the pathogenesis. Human materials for this project has been supplied by the Clinical Center of the National Institutes of Health, and studies were also performed on various experimental animals. Completed projects during this year are: early cytologic changes of Fraser cataract; swelling of the lens fibers in congenital cataract and galactose cataract; cataractous lenses of diabetic sand rats; ocular pathology induced by the suckling mouse cataract agent; extraocular muscules in myotonic dystrophy; Peters' anomaly; pigmentary dispersion syndrome; effect of hyperosmotic agents on the ciliary epithelium and trabecular meshwork; Menkes' kinky hair disease; optic neuropathy caused by vincristine; malignant melanoma of the skin metastatic to the eye; and homologous retinal outer segment immunization in primates.