A decrease in the amount of dopamine in the retina could explain why people with diabetes often have visual problems or even go blind.

Reduced levels of this brain-signalling molecule have been seen in diabetes before, so Machelle Pardue at Emory University in Atlanta, Georgia, and her colleagues gave a dopamine precursor called L-DOPA to rat and mouse models of type 1 diabetes. They found that the molecule delayed the onset and slowed down the progression of early visual dysfunction, and improved the responses of the retina's light-sensing cells.

Treating dopamine deficiency could be a way to combat vision loss associated with type 1 diabetes, the authors say.

J. Neurosci. 34, 726–736 (2014)