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.
Disease of the retina caused by diabetes is called diabetic retinopathy. Changes to the retina are caused by elevated blood sugar levels over an extended period of time, which can damage the blood vessels in the retina. This damage causes the blood vessels of the retina to become clogged and start to bleed, which can lead to bleeding and swelling of the retina. Over time, the clogging of the blood vessels causes the retina to be deprived of oxygen, as a result of which neovascularisation, i.e. the formation of new, fragile blood vessels prone to bleeding, can develop in the back of the eye. These fragile new blood vessels can cause bleeding within the eye, which can pose a threat to vision and require treatment.
Diabetic retinopathy usually develops gradually and can have no symptoms at all. Left untreated, retinopathy can cause permanent visual impairment. For this reason, people with diabetes should ensure they undergo fundus photography (photography of the backs of the eyes) regularly to check for changes to the retina and to catch any changes requiring treatment. Timely and good treatment of both elevated blood sugar levels and retinopathy that requires treatment can significantly reduce the risk of impairment and loss of vision.
Diabetic retinopathy is divided, based on the severity of the changes and their location, into the following categories: background retinopathy, severe background retinopathy or pre-proliferative retinopathy and proliferative retinopathy. The term maculopathy refers to any changes to the area of the back of the eye responsible for detailed vision. Maculopathy can occur at any of the stages of retinopathy.