PARIS • People suffering vision loss may one day have new corneas and lenses grown from their own cells, and be spared the invasive transplants required today, according to new research.

One research team said it had managed to engineer corneas from stem cells in the lab, while another regenerated lenses inside the human eye, in papers published in the journal Nature on Wednesday.

To work perfectly, the cornea and lens must be absolutely transparent. Sometimes, due to disease or ageing, these become opaque and need to be replaced with a donor or artificial transplant. Such procedures are not foolproof, and in some cases the transplants are rejected by the recipient's body.

Stem cells offer hope as they can be taken from the patient's own body, minimising rejection risk.

Stem cells are primitive cells that, as they mature, differentiate into the various specialised cells that make up the different organs.

Until a few years ago, the only way to obtain stem cells was to harvest them from human embryos, a controversial practice. But now scientists have developed induced pluripotent stem cells, or iPSCs, which are mature cells turned back to an earlier, versatile state from which they can re-diversify.

For the first study, scientists in the United States and China developed a new way to remove and replace damaged eye lenses in people with cataracts. The current surgical method leaves a large incision which can easily become inflamed.

In the new procedure, a team extracted the lens through a much smaller hole than the existing procedure requires, and also left behind many more naturally occurring, lens-creating stem cells called LECs. These were stimulated into building a new lens. The method was successful in rabbits and macaques, and later in 12 children.

For the second paper, researchers in Japan and Cardiff used human iPSCs to create eye cells which they grew into healthy corneas in a lab dish and implanted into rabbits.

AGENCE FRANCE-PRESSE