What Is Diabetic Retinopathy?
There are two types of Diabetic Retinopathy: Nonproliferative Diabetic Retinopathy (NPDR) and Proliferative Diabetic Retinopathy (PDR). NPDR, commonly known as “Background Retinopathy,” is an early 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 case of visual loss in diabetes. Vision loss may be mild to severe, but even in the worst cases, peripheral vision continue to function.
Macular Ischemia occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives sufficient blood supply to work properly.
PDR is present when abnormal new vessels (neovascularization) begin growing on the surface of the retina or optic nerve. The main cause of PDR is widespread closure of retinal blood vessels, preventing adequate blood flow. The retina responds by growing new blood vessels in an attempt to supply blood to the area where the original vessels closed. Unfortunately, the new, abnormal blood vessels do not resupply the retina with normal blood flow. The new vessels are often accompanied by scar tissue that may cause wrinkling or detachment of the retina. PDR may cause more sever vision loss than NPDR because it can affect both central and peripheral vision. Proliferative Diabetic Retinopathy causes visual loss in the following ways: Vitreous Hemorrhage: The fragile new vessels may bleed into the vitreous, a clear jelly-like substance that fills the center of the eye. If the Vitreous Hemorrhage is small, a person might see only a few new dark floaters. A very large hemorrhage might block out all vision. Vitreous Hemorrhage alone does not cause permanent vision loss. When the blood clears, visual acuity may return to its former level unless the macula is damaged. Traction Retinal Detachment: When PDR is present, scar tissue associated with neocavascularization can shrink, wrinkling and pulling the retina from its normal position. Macular wrinkling can cause visual distortion. More severe vision loss can occur if the macula or large areas of the retina are detached. Neovascular Glaucoma: Occasionally, extensive retinal vessel closure will cause new, abnormal blood vessels to grow on the iris (colored part of the eye) and block the normal flow of fluid out of the eye. Pressure in the eye builds up, resulting in Neovascular Glaucoma, a sever eye disease that causes damage to the optic nerve.
How Is Diabetic Retinopathy Treated?
The best treatment is to prevent the development or 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. Laser surgery is often recommended for people with Macular Edema, PDR and Neovascular Glaucoma.
