What is Diabetic Retinopathy?
Diabetic Retinopathy is a problem faced by many people who have diabetes (but not all of them), and the chance of retinopathy increases with the duration of the diabetes. Diabetes damages tiny blood vessels that nourish the retina, causing vision changes. As diabetic retinopathy becomes more severe, new blood vessels begin to form on the retina that can break and cause severe vision loss. In the early stages the disease usually goes unnoticed, but as more and more blood vessels are damaged and new ones are formed, the chances of vision loss increases dramatically. According to the National Eye Institute, diabetic retinopathy is a leading cause of blindness in American adults. It is recommended that people with diabetes get a thorough eye examination once a year and maintain good control of their blood-sugar levels through diet, exercise, and regular visits to their primary care provider.
Who is at Risk for Diabetic Retinopathy?
Anyone with diabetes is at risk for developing this eye disease. This is why we will stress throughout this article that all diabetics should visit their eye care professional at least once a year, whether obvious symptoms are present or not. The longer you have diabetes, the more likely you are to develop diabetic retinopathy. In addition, the worse your blood-sugar control, the higher your odds of developing diabetic eye disease. According to the National Eye Institute, up to 40 percent of people diagnosed with diabetes already have some form of diabetic retinopathy.
If an expectant mother is diabetic, she is at risk for this eye disease. If you are pregnant or planning to become pregnant and have diabetes, you should see your eye doctor for a comprehensive eye exam as soon as you are pregnant or begin trying to conceive, and schedule follow-ups visits throughout the gestation period.
Stages of Diabetic Retinopathy
- Background Retinopathy: Small spots of blood appear on the surface of the retina.
- Mild Non-proliferative Retinopathy: Microaneurysms form (small swellings in the retina’s tiny blood vessels).
- Moderate Non-proliferative Retinopathy: Essential blood vessels become blocked. Larger ‘blot’ hemorrhages appear on the surface of the retina.
- Severe Non-proliferative Retinopathy: Even more blood vessels are blocked in the retina, and the blood vessels appear more curvy (tortuous). More spots and blots of blood appear, as well as white patches called “cotton wool spots.” If untreated, this may lead to…
- Proliferative Retinopathy: The growth of abnormal blood vessels on the retina that may bleed, leading to scarring and detachment of the retina. These problems can cause severe damage.
At any stage of diabetic retinopathy a separate condition may develop called macular edema. Macular edema occurs when the part of the retina that provides sharp central vision swells from leaking fluid. This usually causes blurred vision.
Diabetic Retinopathy Symptoms
Diabetic Retinopathy has no early warning signs because vision loss is not noticeable until damage has occurred. As the disease progresses, symptoms may include:
- Floaters in vision
- Vision loss
- Swollen blood vessels inside the eye
- Blood vessels leak fluid
- New blood vessels may appear in eye and begin leaking fluid
- Condition may improve for a short time, only to worsen again
- Difficulty seeing at night
- Shadows or missing areas in field of vision
- Severe vision loss in the proliferative stage
What Causes Diabetic Retinopathy?
The cause of diabetic retinopathy is unknown, but it is believed that the retinas of diabetic patients release a chemical that induces the changes that are seen in the retina. Diabetic retinopathy occurs when the blood vessels inside the retina are damaged and leak. This causes a lack of oxygen in the retina, which causes the retina to release VEGF (vascular endothelial growth factor). This VEGF chemical causes new, fragile blood vessels to grow, which leak even more. In general, diabetic retinopathy is caused by poorly controlled diabetes, and occurs in those who have had diabetes for a long time.
Diagnosing Diabetic Retinopathy
Unfortunately, this eye disease rarely shows symptoms until it has progressed. There is usually no pain and minimal vision trouble while it is in its non-proliferative stages. Still, diabetic retinopathy can be detected in its early stages with annual check-ups. If you have diabetes, you should visit the eye doctor as at least once a year for a complete eye examination with dilation.
Typically, a visual acuity test is given to determine how well you see at various distances. Your eye doctor will check your retina for leaking blood vessels; damaged nerve tissue; pale, fatty deposits on your retina; retinal swelling; or any other changes to the blood vessels.
When the retinopathy reaches the proliferative stage, abnormal blood vessels develop that can bleed, leading to blurred vision. If your eye doctor believes macular edema is present, a fluorescein angiogram may be performed. This test uses a special dye that is injected into the body and tracked and photographed as it flows through the retina and into any leaking blood vessels.
Diabetic Retinopathy Treatment
The first three stages of diabetic retinopathy usually do not require treatment by an eye doctor unless macular edema is present. The progression of diabetic retinopathy can be prevented by controlling blood sugar levels, blood pressure, and blood cholesterol. If you smoke, it is highly recommended that you quit.
Macula edema may be treated with a process called focal laser photocoagulation, which involves using lasers to seal off leakage and shrink leaking blood vessels. Sometimes more than one treatment is needed, but according to the NEI, “Focal laser treatment stabilizes vision. In fact, focal laser treatment reduces the risk of vision loss by 50 percent. In a small number of cases, if vision is lost, it can be improved.” Laser therapy for diabetic retinopathy has a 90 percent success rate when appropriate follow-up care is provided.
If blood leakage is severe, a vitrectomy may be used to clear out blood that has leaked into the vitreous humor. In this procedure, a small incision is made in the eye and vitreous gel that has been filled with blood is removed. The eye is then refilled with a saline solution. Some people stay in the hospital overnight after a vitrectomy, but most people return home the same day. Most people experience red, sensitive eyes and must wear an eye patch to protect the eye for a few days or weeks. Typically, medicated eye drops are prescribed to protect the eyes against infection and excessive inflammation.
Vitrectomy and laser treatment are considered safe and effective for treating diabetic retinopathy, and are better for patients than avoiding treatment. It is unrealistic for a person to think their eye disease will be cured after either procedure, as 5 percent of those with proliferative retinopathy have a chance of becoming blind within five years following treatment. Unfortunately, this figure includes those who receive treatment in a timely manner.
In some cases steroids are injected into the vitreous cavity in order to treat diabetic retinopathy. Triamcinolone is a steroid known to decrease macular edema and increase visual acuity. Unfortunately, these injections do not last as long as other treatment methods—they are effective, on average, for up to three months, after which another injection is needed. This treatment method can also cause cataracts, steroid-induced glaucoma, and endophthalmitis (an infection in the eye). Talk with your eye doctor about the various treatment methods available to you.
When to Contact Your Eye Doctor
If you have diabetes, contact your doctor immediately if you begin experiencing any of the following symptoms of diabetic retinopathy:
- You have blind spots
- You see floaters in your vision
- Your vision becomes blurry or hazy
- You begin to experience double vision
- Headaches develop
- Pain develops in one of your eyes
- Peripheral vision decreases
Preventing Diabetic Retinopathy
Prevention of retinopathy is the best way to avoid vision damage. Annual eye examinations by a qualified eye doctor are an absolute must. Some other steps that may help include maintaining well-controlled blood sugar levels, keeping blood pressure at normal values, eating a healthy diet with normal amounts of cholesterol, not smoking, and exercising regularly. Long-term blood sugar stability can be monitored with a test called Hemoglobin A1c. This blood test measures the overall blood sugar level for the previous three months.
If the symptoms of diabetic retinopathy have already developed, with attendant significant vision loss, talk with your eye doctor about low-vision services and devices that may help you keep your best possible vision. Talk with your eye doctor or health care provider about community resources that provide low vision counseling or training.
Complications of Diabetic Retinopathy
There are several complications that may develop if diabetic retinopathy goes undetected. These problems may include:
- Vision that worsens over time
- Inability to see fine print
- Inability to perform normal tasks
- Increased risk of infection after surgical treatments
- Additional eye diseases may develop, including macular edema, glaucoma, cataracts, and retinal detachment
Diabetic Retinopathy Statistics
There are some new statistics associated with diabetic retinopathy that every diabetic should know about.
- After five years of taking insulin for type 1 diabetes, there is a 25 percent chance of developing diabetic retinopathy. For type 2 diabetes, that number increases to 40 percent for those who are on insulin and 24 percent for those who are not.
- After fifteen to twenty years of taking insulin for type 1 diabetes, there is an 80 percent chance of developing diabetic retinopathy. For type 2 diabetes, that number increases to 84 percent for those on insulin and 53 percent for those who are not.
- As of 2011, it is estimated that 246 million people worldwide have diabetes and that 7 million more will be diagnosed with diabetes each year.
- The US Centers for Disease Control estimates that 12,000 to 24,000 new cases of blindness related to diabetic retinopathy occur each year.
- African American and Hispanic individuals are a greater risk (up to 50 percent more than other races) for developing diabetic retinopathy.
Talking to Your Eye Doctor
Here are some questions to ask your eye doctor about diabetic retinopathy:
- Is there a chance my vision can improve with treatment?
- What treatment options do I have?
- How severe is my condition?
- After examining my eyes, do you see signs of any other eye disease?
- How often should I schedule appointments with you?
- Before treatment, are there any specific steps I need to take?
- If my diabetes gets out of control, how long should I wait to see you?
- Are there any home remedies that might be beneficial to me?
- Can you help me create an appropriate diet plan?
- Are there any over-the-counter medications that can reduce my symptoms?
- Can you give me a referral for a low vision specialist?
- Do you know of any resources for low vision in our community?
- National Eye Institute, 2011 Facts About Diabetic Retinopathy http://www.nei.nih.gov/health/diabetic/retinopathy.asp
- J. Anshel, MD “Smart Medicine for Your Eyes” (SquareOne Publishers, 2011) 199-203
- American Optometric Association, 2011 Diabetic Retinopathy http://www.aoa.org/diabetic-retinopathy.xml
- PR Newswire Scientists for the First Time Regenerate Sections of Retinas and Increase Visual Function With Stem Cells Derived From Skin (May 12, 2011) http://www.prnewswire.com/news-releases/
- J. Weizer, MD, J. Stein, MD, MS “Reader’s Digest Guide to Eye Care” (Quantum Publishing Ltd, 2009) 87: 159