EurekAlert! reports on one line of work in regenerative medicine for the eye: "A special type of cell found in the eye has been found to be very important in regenerating the retina in zebrafish and restoring vision even after extensive damage. ... scientists believe they may be able to use these cells - known as Muller glial cells - to regenerate damaged retina in humans, according to a study published this month in the journal Stem Cells. ... researchers were able to develop the cells in vitro into all the types of neurons found in the retina. When tested in rat models with diseased retinas, the cells migrated into the retina and took on the characteristics of the surrounding neurons. The researchers are now looking at developing this approach for use in the human eye. In addition to growing the cells in the lab and transplanting them back into the eye, the researchers are looking at ways to stimulate growth and persuading the eye to repair itself using its own cells. ... Although Muller glial cells are present in the human eye, it is not clear whether they already automatically repair the retina in some people but not in others. It is possible that internal mechanisms exist in the normal adult retina that prevent these cells from dividing and replicating. ... Our next step is to identify which factor is responsible for blocking the regeneration."