Patients sleeping in a low-lit room may find that the changes in diabetic macular oedema (DME) are reversed, claims a study in Eye.

Dr G.B. Arden et al., School of Community and Health Sciences, City University, London, UK, conducted an investigation on 40 patients with mild non-proliferative diabetic retinopathy (DR) and early, untreated non-sight threatening DME. For six months all patients slept with a mask that illuminated the eyelid of a single closed eye with a 505 nm light.

The exclusion criteria were the presence of any concomitant eye disease and the primary outcome was the change in OCT retinal thickness where oedema was present.

Of the 40 patients observed, 34 completed the investigation. For study and fellow eyes the mean baseline OCT macular cube thickness was equivalent. It was found that the study eyes presented with a greater thickness in the central subfield zone 1 compared to the fellow eyes.

Intraretinal cysts were found in 28 eyes, compared to 9 found in the fellow eyes. Only 19 study eyes presented with cysts at 6 months, whilst 20 fellow eyes had cysts. In study eyes the worst affected ETDRS zone and the central subfield zone 1 experienced a reduction in thickness by 12μm.

In study eyes visual acuity, achromatic contrast sensitivity and microperimetric thresholds improved and in the fellow eyes they deteriorated