If you have diabetes, your body does not use and store sugar properly. High blood sugar levels can damage blood vessels in the retina, the nerve layer at the back of the eye that senses light and helps to send images to the brain. The damage to retinal vessels is referred to as diabetic retinopathy.
Diabetic retinopathy, the most common diabetic eye disease, occurs when blood vessels in the retina change. Sometimes these vessels swell and leak fluid or even close off completely. In other cases, abnormal new blood vessels grow on the surface of the retina.
Diabetic retinopathy usually affects both eyes. People who have diabetic retinopathy often don't notice changes in their vision in the disease's early stages. But as it progresses, diabetic retinopathy usually causes vision loss that in many cases cannot be reversed.
Nonproliferative diabetic retinopathy (NPDR)
NPDR is the earliest stage of diabetic retinopathy. In this stage, tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposits called exudates.
Many people with diabetes have mild NPDR, which usually does not affect their vision. When vision is affected it is the result of macular edema and/or macular ischemia.
Macular edema is swelling or thickening of the macula, a small area in the center of the retina that allows us to see fine details clearly. The swelling is caused by fluid leaking from retinal blood vessels. It is the most common cause of visual loss in diabetes. Vision loss may be mild to severe, but even in the worst cases, peripheral vision continues to function.
Macular ischemia occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives enough blood supply to work properly.
Proliferative diabetic retinopathy (PDR)
Proliferative diabetic retinopathy (PDR) mainly occurs when many of the blood vessels in the retina close, preventing enough blood flow. In an attempt to supply blood to the area where the original vessels closed, the retina responds by growing new blood vessels. This is called neovascularization. However, these new blood vessels are abnormal and do not supply the retina with proper blood flow. The new vessels are also often accompanied by scar tissue that may cause the retina to wrinkle or detach.
PDR may cause more severe vision loss than NPDR because it can affect both central and peripheral vision. PDR affects vision in the following ways:
You can have diabetic retinopathy and not be aware of it, since the early stages of diabetic retinopathy often don't have symptoms. As the disease progresses, diabetic retinopathy symptoms may include:
The best treatment is to prevent the development of retinopathy as much as possible. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss from diabetic retinopathy. If high blood pressure and kidney problems are present, they need to be treated.
People with diabetes should schedule examinations with CNY Eye Physicians & Surgeons at least once a year. More frequent medical eye examinations may be necessary after a diagnosis of diabetic retinopathy. Pregnant women with diabetes should schedule an appointment in the first trimester, because retinopathy can progress quickly during pregnancy. If you need to be examined for eyeglasses it is important that your blood sugar be consistently under control for several days when you see your ophthalmologist. Eyeglasses that work well when blood sugar is out of control will not work well when blood sugar is stable. Rapid changes in blood sugar can cause fluctuating vision in both eyes even if retinopathy is not present.
You should have your eyes checked promptly if you have visual changes that: affect either one or both eyes; last more than a few days; are not associated with a change in blood sugar. When you are first diagnosed with diabetes, you should have your eyes checked: within five years of the diagnosis if you 29 years old or younger; within a few months of the diagnosis if are 30 years old and older.