In diabetic patients, damage to the eyes (diabetic retinopathy) is classified in 4 stages: mild, nonproliferative retinopathy, moderate, severe and finally proliferative retinopathy, which left untreated will result in blindness. Monitoring glucose levels in the blood (glycaemia) aiming for an HbA1c level of 7% and maintaining blood pressure below 140/80 mm Hg reduce the risk of diabetic retinopathy appearing.
In the case of severe retinopathy, there are effective treatments to prevent blindness, which are helpful even before the vision deteriorates. In the case of proliferative or nonproliferative but severe retinopathy, laser treatment can reduce the risk of blindness or of a severe reduction in visual acuity by half, without reducing an existing visual deficit.
Laser treatment is also recommended for some forms of macular oedema. Vitrectomy (removal of the damaged portion of the vitreous body) is suited to some cases of complicated proliferative retinopathy.
Compared with laser treatment, intravitreal drug injections have a less favourable and less well established risk-benefit balance.
Patients should be given regular eye check-ups, even when their eyesight is good.
©Prescrire February 2010
"Preventing blindness due to diabetic retinopathy" Prescrire Int 2010; 19 (105): 35-38.