A new study has revealed that stem cell treatment may be helpful in treating blindness.
According to the study, a pioneering treatment for progressive blindness has been proved safe three years after patients were injected with stem cells derived from human embryos.
The researchers said that more than half of the patients with macular degeneration - where the eye's light-sensitive cells are progressively destroyed - experienced a significant improvement in their eyesight, but none showed any adverse effects due directly to the transplant of the embryonic cells.
Doctors injected the stem cells into the eyes of 18 patients - nine with Stargardt's macular dystrophy and nine with dry, age-related macular degeneration - with the ultimate aim of repairing damaged photoreceptors in the retina at the back of the eye.
It was found that about half of the patients had an improvement in visual acuity of three lines or more, which corresponds to a doubling of the visual angle, and is generally accepted as clinically significant.
Follow-up testing found that 10 out of the 18 patients experienced substantial improvements in how well they could see.
The study was published in the journal The Lancet.