A new study suggests that illumination during the hours of darkness might prevent retinal damage in diabetes.

One of the major complications of diabetes is a form of blindness called diabetic retinopathy. This results from damage to the retina - the layer of tissue at the back of the eye which responds to light. In diabetes, the blood supply to the eye is impaired and this has an impact on the rods (the cells responsible for night vision) which have a high demand for oxygen.

Researchers at the University of Cardiff, Wales, have found that night time illumination can reduce the rods' demand for oxygen. The work was done with seven patients with type 2 diabetes and eight healthy controls. It opens up the possibility that some kind of transmission of light through closed eyelids, during sleep, could protect the retina from damage by reducing the oxygen requirements of the rod cells.

Source

Lancet 29th June 2002