Diabetic retinopathy. Artwork of the retina of the eye (ophthalmoscope view) in a diabetic patient. Diabetic retinopathy is caused by damage to the blood supply of the retina the lightsensitive membrane inside the back of the eye. The condition occurs as a complication of diabetes. Here, discolouration of the retina fundus (or blind spot, yellow) is seen. The red patches are haemorrhages, caused by blood leaking from blocked capillaries, with resulting reduction in blood flow to some areas of the retina. The yellow spots are fatty exudates, caused by increased permeabil ity of blood vessels. Retinopathy impairs sight and can lead to blindness.