Diabetes can affect blood vessels and organs throughout the body. It can particularly affect the eye causing a condition known as diabetic retinopathy. Diabetic retinopathy is a disease in which the retina is starved of oxygen and ultimately damaged. The condition develops when many years of high blood sugars, often aggravated by high blood pressure and cholesterol, causes severe injury to the blood vessels that supply oxygen to the retina. The vessels often begin to function poorly and can even leak fluid into the center of the retina, called the macula. Other complications include macular swelling, called macular edema, which can also lead to impaired vision. When treated properly, diabetic retinopathy and its effects are reversible; when ignored, it can lead to permanent vision loss and other health problems.
Who is most at risk for diabetic retinopathy?Anyone with Type I (juvenile onset) or Type II (adult onset) diabetes is at risk.
What are the symptoms?Diabetic retinopathy often has no early warning signs. At some point, though, you may develop macular edema, which blurs vision, making it hard to do things like reading and driving.. In some cases, your vision will get better or worse during the day. As new blood vessels form at the back of the eye, they can bleed (hemorrhage) and blur vision. The first time this happens it may not be very severe. In most cases, it will leave just a few specks of blood, or spots, floating in your vision. They often go away after a few hours. These spots are often followed within a few days or weeks by a much greater leakage of blood. The blood, too, will blur your vision. In an extreme case, one will only be able to tell light from dark in that eye. It may take the blood anywhere from a few days to months or even years to clear from the inside of the eye. In some cases, the blood will not clear. Also, you should be aware that large hemorrhages tend to happen more than once, often during sleep. Also, patients with diabetes tend to develop cataracts earlier.
How is it detected?It is very important that patients with Diabetes get a dilated exam at least once a year to screen for any retinal changes associated with this condition as early detection is the best protection against loss of vision. Pregnant women with diabetes should schedule an appointment in their first trimester because retinopathy can progress quickly during pregnancy. In our practice, patients typically have seen their optometrist or ophthalmologist (Eye M.D.) prior to being referred to us for a more specialized evaluation. More frequent medical eye examinations may be necessary after a diagnosis of diabetic retinopathy. Diabetic retinopathy is detected during an eye examination that includes:
- Visual acuity test: Eye chart test measures how well you see at various distances.
- Pupil dilation: Drops are placed into the eye to enlarge the pupil. This allows us to see more of the retina and look for signs of diabetic retinopathy. After the examination, close-up vision may remain blurred for several hours.
- Ophthalmoscopy: This is an examination of the retina in which the eye is examined by looking through a device with a special magnifying lens or using a bright light to look through a special magnifying glass to look at the retina.
- Optical Coherence Tomography (OCT): This device helps us better assess macular edema in high resolution and provides an objective way to monitor response to treatment.
- Fluorescein Angiography: Should we suspect that you need treatment for macular edema, we may ask you to have a test called fluorescein angiography, during which a special dye is injected into the arm and photographed as it passes through the blood vessels in the retina. This test allows us to find the leaking blood vessels and to target them during laser surgery.
What is Non-proliferative Diabetic Retinopathy?Nonproliferative diabetic retinopathy (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 or macular ischemia, or both.
What is Macular Edema and 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 (side) vision continues to function. Laser treatment can be used to help control vision loss from macular edema. Some patients benefit from the use of intraocular steroid injection. Newer treatments are being investigated such as use of anti-VEGF treatment in this condition. Macular ischemia occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives sufficient blood supply from working properly. Unfortunately, there are no effective treatments for macular ischemia.
What is Proliferative Diabetic Retinopathy?Proliferative diabetic retinopathy (PDR) is a complication of diabetes caused by changes in the blood vessels of the eye. If you have diabetes, your body does not use and store sugar properly. High blood sugar levels create changes in the veins, arteries, and capillaries that carry blood throughout the body. This includes the tiny blood vessels in the retina, the light-sensitive nerve layer that lines the back of the eye. In PDR, the retinal blood vessels are so damaged they close off. In response, the retina grows new, fragile blood vessels. Unfortunately, these new blood vessels are abnormal and grow on the surface of the retina, so they do not resupply the retina with blood. Occasionally, these new blood vessels bleed and cause a vitreous hemorrhage. Blood in the vitreous, the clear gel-like substance that fills the inside of the eye, blocks light rays from reaching the retina. A small amount of blood will cause dark floaters, while a large hemorrhage might block all vision, leaving only light and dark perception. The new blood vessels can also cause scar tissue to grow. The scar tissue shrinks, wrinkling and pulling on the retina and distorting vision. If the pulling is severe, the macula may detach from its normal position and cause vision loss. Laser surgery may be used to shrink the abnormal blood vessels and reduce the risk of bleeding. The body will usually absorb blood from a vitreous hemorrhage, but that can take days, months, or even years. If the vitreous hemorrhage does not clear within a reasonable time, or if a retinal detachment is detected, an operation called a vitrectomy can be performed. During a vitrectomy, the eye surgeon removes the hemorrhage and any scar tissue that has developed, and performs laser treatment to prevent new abnormal vessel growth. People with PDR sometimes have no symptoms until it is too late to treat them. The retina may be badly injured before there is any change in vision. There is considerable evidence to suggest that rigorous control of blood sugar decreases the chance of developing serious proliferative diabetic retinopathy. Visit our Diabetic Eye Disease page for information on treatment options.
For information and consultation regarding treatment for Diabetic Retinopathy, contact our main office at (405) 607-6699.