The human equivalent to the mouse cells, however, would have to be isolated from fetal retinas, posing the familiar problem of finding a source for the immature cells.

• 然而如果将小鼠研究结果换到人类身上，则将需要摘取胎儿的视网膜做为移植细胞，因此同样面临了未成熟细胞来源的困境。