Previous efforts to do this have failed. According to MacLaren, the trick seemed to be to use stem cells that had stopped dividing and were beginning to actually turn into photoreceptors just before transplanting them into the host.

While it remains to be seen if this mouse experiment applies to humans, researchers say that creating supplies of transplantable cells in the lab should not be a problem. It's already possible to make human embryonic stem cells turn into photoreceptors, says Lanza. "So this study is suggesting that we already have the raw materials we need in the lab."

What's more, there is evidence to suggest that stem cell-like cells exist within adult eyes, says MacLaren. The hope is that they can be harvested from the patient and reimplanted once they have differentiated into photoreceptors.

The eye is largely ignored by the immune system, so the hope is that patients receiving transplants will not need to take immunosuppressant drugs. But if stem cells can indeed be harvested from the patient, then the risk of rejection would be reduced even more, says MacLaren.