The discovery of human embryonic stem (ES) cell lines led to the development of the concept of transplanting stem cells with the potential to differentiate into blood cells, nerve cells and muscle cells. Not only the current standards for transplantation medicine, but the quality of medical services will definitely improve once human ES cells become available. If successful extracorporeal generation of tissues or organs by means of tissue culture is accomplished, it will facjlitate regeneration medicine, by which not only transplantation of cells, but also replacement of whole diseased organs or tissues may become a viable objective. Stem cell transplantations in the form of bone marrow transplantation have been extensively applied clinically. Significant advancements in research related to human skin and intestinal mucosal stem cells have already been attained. Following the recent identification of the presence of corneal stem cells, transplantation of the corneal epithelial stem cells has been initiated. The manufacture of corneal epithelial sheets by in eritro incubation of stem cells and their clinical application to transplantation was reported in 2000. Another ongoing project attempts to produce each of the three layers comprising the structure of the cornea separately, and to combine these to produce an artificial cornea. Further research in this area will enable corneal transplantations to use regenerated ES cells or autogenous stem cells while eliminating any reliance on eye bank stem cells.

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