Researchers have created light-sensitive eye cells out of human stem cells.

"We have basically created a miniature human retina in a dish that not only has the architectural organization of the retina but also has the ability to sense light," study leader M. Valeria Canto-Soler, Ph.D., an assistant professor of ophthalmology at the Johns Hopkins University School of Medicine, said in a news release. "Advances opportunities for vision-saving research and may ultimately lead to technologies that restore vision in people with retinal diseases."

The phenomenon of vision relies on different types of cells working in tandem to turn light into what can be perceived as an image. The researchers noted that they did not create an entire functional eye.

"Is our lab retina capable of producing a visual signal that the brain can interpret into an image? Probably not, but this is a good start," Canto-Soler said in the new release.

The iPS cells are adult cells that have been programed back to their primary state in which they have the ability to grow into almost any kind of cell.  The researchers decided to try turning them into "light-sensitive retinal tissue."

The retinal growth (which took place in a petri dish)corresponded with  the a human fetus in the womb.

 "We knew that a 3-D cellular structure was necessary if we wanted to reproduce functional characteristics of the retina," Canto-Soler said in the news release, "but when we began this work, we didn't think stem cells would be able to build up a retina almost on their own. In our system, somehow the cells knew what to do."

When the retinal tissue had developed to the equivalent of 28 weeks in the womb the researchers tested it to see if it could "sense and transform" light signals.

They placed an electrode on a photoreceptor and gave it a pulse of light; the cell reacted with a biochemical pattern similar to what would be seen in a human eye.

The finding could help lead to treatments for disorders of the retina such as retinitis pigmentosa.