Researchers in Japan say they have succeeded in growing the world's first artificial eyeball.

They said the process could help develop treatments for people with eye problems.

The scientists at Tokyo University have been experimenting with tadpoles in an effort to develop treatments for the blind.

They removed cells from frog embryos and then implanted them in the tadpoles.

'No rejection'

The leader of the team, biologist Makoto Asashima, said a cell was first soaked in a special medium and was then transplanted into a tadpole whose left eye had been removed.

A week later the researchers confirmed that the eyeball was connected to the optic nerves and there was no sign of it being rejected.

Professor Asashima said the process could have applications for human beings and could lay the groundwork for providing treatments for the visually impaired.

Other scientists have yet to assess the significance of the experiment.