Diabetic Retinopathy
If you have diabetes mellitus, your body does not use and store sugar properly. In diabetes, high blood sugar levels can damage the blood vessels in the retina, the nerve layer at the back of the eye that senses light and helps send images to the brain. Damage to the retinal vessels is called diabetic retinopathy. There are two types: non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).
Symptoms
Non-proliferative diabetic retinopathy is an early stage condition. In NPDR, tiny blood vessels within the retina leak blood or fluid, causing the retina to become swollen. This swelling is called macular edema, and it is one of the primary causes of blurry vision in diabetics. Retinal blood vessels can also become completely closed, causing retinal tissue to die in some areas. This condition is called macular ischemia and it also results in blurry vision.
Proliferative diabetic retinopathy is a more advanced condition where abnormal new blood vessels begin to grow within the retina to supply blood to areas where the original blood vessels have become closed. Unfortunately, these blood vessels not only can cause severe bleeding within the eye (vitreous hemorrhage), but can also cause detachment and scarring of the retina (traction retinal detachment). Abnormal blood vessels can also grow on the iris (the colored part of the eye) and block the normal flow of fluid out of the eye, resulting in a painful rise in eye pressure (neovascular glaucoma).
Treatments
The best treatment is to prevent the development of diabetic retinopathy as much as possible by strict control of blood sugar and blood pressure. When diabetic retinopathy develops, laser treatment is used to selectively treat leaky blood vessels to decrease retinal swelling. Laser treatment can also be used to induce regression of abnormal new blood vessels. In cases of severe hemorrhage and/or detachment of the retina, microsurgery can be performed within the eye to remove blood and reattach the retina.