A study of zebrafish has led to a breakthrough which could result in treatments for blindness within five to ten years.
Scientists previously thought that the ability of the tropical fish to repair damage and disease in its own eyes was unique.
However, British researchers announced yesterday that they had found that the cell responsible for the retinal repair is present in human as well as fish eyes.
Muller glial cells can mutate into different kinds of cell, including those which make up the neurons found on the retina.
Although they appear in the human eye, they do not seem to be active, according to the researchers.
The team, from University College London (UCL), successfully grew the stem cells in the laboratory.
In the future, laboratory-grown cells could be implanted into human eyes, restoring the sight of those with retina damage.
Dr Astrid Limb, of UCL's institute of ophthalmology, said: "Our findings have enormous potential. They could help in all diseases where the neurons are damaged, which is basically nearly every disease of the eye."
These include macular degeneration, glaucoma and diabetes, which together account for three-quarters of registered blindness in the UK.