In what marks important progress toward a future where defective vision could be treated with lab-grown eyeball components, an international team of scientists has used human stem cells to build layers of eye tissue that was then implanted into rabbits to restore vision. With promising early results, the researchers say their findings could usher in trials where such transplantations are put to the test in humans.

Stem cells have shown exciting potential in improving the vision of patients with degenerative eye disorders for years. In 2010, scientists reported the creation of the first early-stage retina engineered with human embryonic stem cells. Then in 2012, two legally blind patients experienced improvements to their vision after receiving transplants of retinal cells, also derived from human embryonic stem cells.

But what sets this latest achievement apart is that scientists from Osaka and Cardiff University's were able to use human stem cells to reproduce something closer to the complex nature of the entire eyeball. Using induced pluripotent stem cells, or cells derived directly from adult cells, they were able to cultivate multiple cell lineages of the eye, including the lens, cornea and conjunctiva.

Transplanting the tissues into rabbits with induced corneal blindness saw the front of the eye repaired and vision restored. The team says that this success could lead to clinical trials of similar transplants to repair damaged vision in humans.

"This research shows that various types of human stem cells are able to take on the characteristics of the cornea, lens and retina," says Professor Andrew Quantock, co-author of the study. "Our work not only holds potential for developing cells for treatment of other areas of the eye, but could set the stage for future human clinical trials of anterior eye transplantation to restore visual function."

The research was published in the journal Nature.