Scientists plan to carry out clinical trials in humans with worsening vision, following "exciting" research on mice to treat blindness.

Mice which had lost sight after suffering retinal degeneration, were able to detect light after having stem cell transplants.

While researchers cautioned that restoring sight in people was some way off, they have proposed to move on to human trials after further animal testing.

The mice in the study were transplanted with stem cells which had been grown into small patches of light-sensitive retina - the thin layer of tissue lining the back of the eye.

The research is said to be the first time photoreceptors - the light-sensitive neurons in the eye - have been successfully transplanted to host cells and sent visual signals to the host retina and brain.

Report author Michiko Mandai said: "Transplanting retinal tissue instead of simply using photoreceptor cells allowed the development of more mature, organized morphology, which likely led to better responses to light."

The Japanese study, published in Stem Cell Reports, showed mice who had implants were able to make associations with light, provided that a substantial amount of the transplant was located in the correct place.

The authors said this showed the new cells in the retina not only responded to light but also that the information travelled to the brain and could be used to learn.

Professor Robert MacLaren, Professor of Ophthalmology at the University of Oxford, said the research gave hope for people with poor sight.

He said: "This study is exciting because it shows that a complicated part of the central nervous system, such as the retina, could potentially be regenerated from something as simple as a skin cell.

"Furthermore, the engineered retinal tissue appears to be able to make connections to the brain after transplantation.

"Clinical treatments are still a long way off but, for patients with retinal degeneration, this provides some hope for the future."