Dr. Leure-duPree is involved in comparative, developmental, and evolutionary studies of the visual system emphasizing synaptic organization of the retina by means of light and electron microscopy. Golgi studies (both light and electron microscopic) of the retina are also underway. He is also involved in the study of the biochemical, morphological, and electrophysiological effects of changes in dietary intake on ocular tissues, with emphasis on the neural retina, the retinal pigment epithelium (RPE) and liver. Light and electron microscopic observations are correlated with biochemical data, especially retinoid levels. The role of trace metals in the maintenance of normal RPE cell metabolism and maintenance of the integrity of the photoreceptor is also being investigated.