Cells derived from the sclera and the choroid of 15 donors proliferated to attain a 10(8)-fold increase in the number of cells within 4 months. At each passage, groups of cells differentiated into cells with neuronal morphology, expressing neuronal markers confirmed by immunocytochemistry and RT-PCR analyses, such as beta-tubulin-III, neurofilament, and tau. Parallel to neuronlike formation, glialike cells, revealed by expression of vimentin and P0, were generated in large amounts