Diabetic retinopathy is a potential complication of both type 1 and type 2 diabetes. This disorder develops because fluctuating blood sugar levels can damage the blood vessels of the eye. People with diabetes are most at risk of this eye disease if their blood sugar levels are not well controlled, because chronically high levels of blood sugar promote inflammation. Blood vessels in the eyes are particularly vulnerable to this inflammation because of their small size and delicacy. Diabetic retinopathy symptoms can include blurred vision and black, floating spots in the field of vision. If the condition progresses, partial or full blindness can result.
Retinopathy, or retinal damage, is the most common eye disease that can affect people with diabetes. The retina is a thin layer of tissue located at the back of the eye, and it is the focal point at which images entering the eye are received and transmitted to the brain. Damage to the retina can prevent the reception and transmission of images, leading to vision loss and blindness. The main factor causing retinal damage is inflammation that is directly caused by high blood sugar, but other factors relating to blood sugar levels can lead to diabetic retinopathy symptoms. For example, abnormally high levels of sugar in cells can cause abnormal protein reactions, which can negatively affect many aspects of cell function.
Diabetic retinopathy develops in two stages, each of which has slightly different diabetic retinopathy symptoms. The first stage is called non-proliferative diabetic retinopathy, and the second is called proliferative retinopathy. Non-proliferative diabetic retinopathy can be further divided into mild, moderate and severe categories based on the severity of the eye damage.
Non-proliferative diabetic retinopathy develops when chronic high blood sugar levels lead to blood vessel inflammation and microaneurysms. These are small areas of swelling in the blood vessels of the retina. As the disease progresses to the moderate stage, retinal blood vessels become blocked, and in the severe stage, progressively more vessels are blocked. In the non-proliferative stage, diabetic retinopathy symptoms are not always present. When they do appear, symptoms typically are limited to blurred vision and the occasional presence of floating black spots in the field of vision.
In proliferative retinopathy, new blood vessels begin to grow in the retina in an attempt to repair the damage. These new vessels do not cause any symptoms, but they are fragile and prone to breaking. Further diabetic retinopathy symptoms can develop if these blood vessels break. Broken vessels can leak blood and can cause severe vision loss or even blindness.
Retinopathy symptoms take many years to develop, because in the early stages of the disease, retinal damage is asymptomatic. Sometimes, symptoms do not appear until irreparable damage has been done to the retina, causing vision loss that cannot be restored. For this reason, people with diabetes are encouraged to undergo annual eye checks to help maintain eye health and vision.