Totally blind mice have had their sight restored by injections of light-sensing cells into the eye, UK researchers report.
The team in Oxford said their studies closely resemble the treatments that would be needed in people with degenerative eye disease. Similar results have already been achieved with night-blind mice.
Experts said the field was advancing rapidly, but there were still questions about the quality of vision restored.
Patients with retinitis pigmentosa gradually lose light-sensing cells from the retina and can become blind.
The research team, at the University of Oxford, used mice with a complete lack of light-sensing photoreceptor cells in their retinas. The mice were unable to tell the difference between light and dark.