In a major breakthrough in the field of regenerative medicine, scientists have for the first time created a part of the eye critical for vision using animal stem cells, according to a study published Wednesday in the journal Nature.

The research could pave the way to new treatments for blindness and human eye diseases, and experts say it may even be possible to one day restore vision with transplanted retinas generated from a patient's own stem cells.

The researchers, led by Yoshiki Sasai of the RIKEN Center for Developmental Biology in Japan, conducted lab experiments using mice.  They started with pluripotent stem cells, the universal stem cells for nearly every specialized cell in an organism.  Until now, stem cells have mainly been viewed as a potential source of replacement tissue composed of a single type of cell, like muscle cells, for example.   The ability to generate a more complex set of cells, or even an entire organ, was thought to require intricate chemical interactions with neighboring tissues during gestation, and therefore impossible in the absence of the natural process of cell division and growth.

However, Sasai and colleagues used new techniques, and were able to set in motion the transformation of mouse embryonic stem cells into an optic cup -- the layered, three-dimensional structures that become the retina in an eye.

Most importantly, the cells did the work themselves, without being pushed into any particular shape.