Pioneering research raised hopes of a stem cell treatment for a form of blindness that affects thousands of children.
Scientists successfully implanted cells from healthy mice into animals with the hereditary disease Leber Congenital Amaurosis (LCA).
The implanted cells produced a protein called Crx which is needed to make healthy cone and rod photoreceptors, the light detectors at the back of the eye responsible for sight.
The cells were able to integrate with the retina to become new cone photoreceptors.
Further studies are needed to see if the technique really can help to restore vision.
Dr Jane Sowden, who led the UK research, said: "The newly developed cones look as good as new.
"This is an important step forward as cone photoreceptors are essential for reading vision and for colour vision, and loss of this type of cell has the biggest impact on sight."