Cation shifts in human retina-choroid.

Human ocular tissues from 50 donor eyes were elementally and morphologically analyzed in order to correlate the elemental content and distribution of Ca, Ba, Cr, Cu, Zn, and Se with ocular morphology, sex, race, irideal pigmentation, age, time of death, birth weight, presence and severity of diabetes, and other pathologies noted at autopsy. Initially, to facilitate the transport of donor tissue to the laboratory, the eyes were fixed in glutaraldehyde. Because our preliminary data revealed alterations in elemental content following chemical fixation of ocular tissues, all of the subsequent samples were analyzed in their fresh, hydrated (unfixed) condition as soon after enucleation as possible. Samples were elementally analyzed by X-ray fluorescence spectrometry (XRF) and proton-induced X-ray emission spectrometry (PIXE) using high resolution Si(Li) X-ray detectors. Tissue was morphologiscally examined by scanning electron microscopy and light microscopy histoichemistry.