Nightlight Therapy

Going to sleep with a light on may help diabetics reduce their risk of developing a serious complication which can cause blindness, scientists said on Friday.

Diabetic retinopathy, which damages the retina of the eye, affects up to half of all diabetes sufferers. The disease damages tiny blood vessels in the light-sensitive tissue at the back of the eye, called the retina, which can cloud vision.

But Professor Neville Drasdo, of Cardiff University in Wales, said night-time illumination may help prevent the condition.

Diabetes causes damage by reducing the uptake of oxygen to body tissue, including the retina. Scientists suspect that oxygen deprivation to the inner layers of the retina during the hours of darkness could be related to diabetic retinopathy.

When Drasdo and his colleagues studied the impact of night-time light on seven patients with Type 2, or adult onset, diabetes and eight healthy volunteers they found it helped to counteract the impact of the darkness in the diabetes patients.

"The finding strengthens support for the suggestion that diabetic patients might benefit from sleeping with night-time illumination," Drasdo said in a letter to The Lancet medical journal.

Diabetic retinopathy has no early warning signs. The blood vessels can bleed and leave a few specks of blood or spots which may disappear but sometimes it does not clear.

Large hemorrhages can happen more than once and often occur during sleep.