The picture shows a black-and-white image of a healthy back surface of an eye. The area of sharp vision, the macula, can be seen as a dark area in the middle. The arteries entering the retina from the end of the optic nerve (papilla) on the right are shown in a lighter colour, while the veins are darker and thicker.
The retinal disease caused by diabetes is called diabetic retinopathy. Normally, diabetic retinopathy develops gradually, and it may be completely asymptomatic. That is why everyone with diabetes should have the back surfaces of their eyes regularly checked in order to establish changes in the retina and identify any changes that require treatment. If diabetic retinopathy goes untreated, it can cause a permanent vision impairment.
Depending on the severity and locations of the changes, diabetic retinopathy is classed into mild, moderate or severe background or Non-Proliferative Diabetic Retinopathy (NPDR) and severe or Proliferative Diabetic Retinopathy (PDR). Changes in the area of accurate vision of the fundus is called maculopathy, which can be related to retinopathy of any severity.
Retinal changes of some degree are manifest in nearly everyone with type 1 diabetes after a couple of decades. Approximately 30%–40% of cases include severe retinopathy.
In people with type 2 diabetes, retinal changes may occur already when diabetes is first diagnosed, if the first diagnosis was late. Severe retinopathy is rarer than in type 1 diabetes. Changes in the central part of the retina, called maculopathy, is more common in type 2 diabetes than in type 1 diabetes.