They have identified a chemical in the eye that triggers the dormant capacity of certain non-neuronal cells to transform into progenitor cells - a stem-like cell that can generate new retinal cells.

According to the researchers, the discovery offers new hope to people suffering from diseases that harm the retina, such as macular degeneration and retinitis pigmentosa.

"This study is very significant. It means it might be possible to turn on the eye's own resources to regenerate damaged retinas, without the need for transplanting outside retinal tissue or stem cells," said Dr. Dong Feng Chen, associate scientist at Schepens Eye Research Institute and Harvard Medical School, and the principal investigator of the study.

Scientists are already aware of Muller cells and they have generally assumed that they kept retinal tissue protected and clear of debris.

However, in recent years, researchers have reported that these cells sometimes exhibit progenitor cell behaviour and re-enter the cell cycle.

Progenitor cells are like stem cells but are more mature and are more limited in the number of cells types they can become.

However, until this study, researchers couldn't understand what triggers the transformation.

In the new study, Chen and her research team found that when the naturally occurring chemicals known as glutamate and aminoadipate were injected into the eye, the Muller cells began to divide and proliferate.