Diabetic retinopathy

Overview

Diabetic retinopathy is a retinal problem that affects people with high blood sugar. It is a diabetes complication that affects eyes. If your blood sugar routinely reaches unhealthy levels, the blood vessels in your eyes may become damaged, abnormal blood vessels may grow and scar tissue may form and damage your retina and your eyesight. This condition is known as diabetic retinopathy, the leading cause of blindness in the.

At first, diabetic retinopathy may cause no symptoms or only mild vision problems. Eventually, it can cause blindness.

The condition can develop in anyone who has type 1 or type 2 diabetes. The longer you have diabetes and the less controlled your blood sugar is, the more likely you are to develop this eye complication. If you have diabetes, see an ophthalmologist for a full eye exam yearly. Finding and treating problems early may save your sight. If your vision changes suddenly or becomes blurry, spotty or hazy, schedule an exam by one of our ophthalmologists right away.

Symptoms

You might not have symptoms in the early stages of diabetic retinopathy. As the condition progresses, diabetic retinopathy symptoms may include:

• Spots or dark strings floating in your vision (floaters)
• Blurred vision
• Fluctuating vision
• Impaired colour vision
• Dark or empty areas in your vision
• Vision loss

Diabetic retinopathy usually affects both eyes.

When to see a doctor

Protecting yourself against diabetes is the best way to avoid retinopathy. If you are already diabetic, regular eye exams, controlling your blood sugar, and blood pressure are essential to preventing this disease.

Careful management of your diabetes is the best way to prevent vision loss. If you have diabetes, see your eye doctor for a yearly eye exam with dilation — even if your vision seems fine. Pregnancy may worsen diabetic retinopathy, so if you’re pregnant, your eye doctor may recommend additional eye exams throughout your pregnancy.

Contact your eye doctor right away if your vision changes suddenly or becomes blurry, spotty or hazy.

Causes

Diabetic retinopathy

Over time, too much sugar in your blood can lead to the blockage of the tiny blood vessels that nourish the retina, cutting off its blood supply. As a result, the eye attempts to grow new blood vessels. But these new blood vessels don’t develop properly and can leak easily.

There are two types of diabetic retinopathy:

• Early diabetic retinopathy.In this more common form — called nonproliferative diabetic retinopathy (NPDR) — new blood vessels aren’t growing (proliferating).

When you have NPDR, the walls of the blood vessels in your retina weaken. Tiny bulges (microaneurysms) protrude from the vessel walls of the smaller vessels, sometimes leaking fluid and blood into the retina. Larger retinal vessels can begin to dilate and become irregular in diameter, as well. NPDR can progress from mild to severe, as more blood vessels become blocked.

Nerve fibres in the retina may begin to swell. Sometimes the central part of the retina (macula) begins to swell (macular oedema), a condition that requires treatment.

• Advanced diabetic retinopathy.Diabetic retinopathy can progress to this more severe type, known as proliferative diabetic retinopathy. In this type, damaged blood vessels close off, causing the growth of new, abnormal blood vessels in the retina, and can leak into the clear, jelly-like substance that fills the centre of your eye (vitreous).

Eventually, scar tissue stimulated by the growth of new blood vessels may cause the retina to detach from the back of your eye. If the new blood vessels interfere with the normal flow of fluid out of the eye, pressure may build up in the eyeball. This can damage the nerve that carries images from your eye to your brain (optic nerve), resulting in glaucoma.

Risk factors

Anyone who has diabetes can develop diabetic retinopathy. Risk of developing the eye condition can increase as a result of:

• Duration of diabetes — the longer you have diabetes, the greater your risk of developing diabetic retinopathy
• Poor control of your blood sugar level
• High blood pressure
• High cholesterol
• Pregnancy
• Tobacco use
• Being African-American, Hispanic or Native American

Complications

Diabetic retinopathy involves the abnormal growth of blood vessels in the retina. Complications can lead to serious vision problems:

• Vitreous haemorrhage.The new blood vessels may bleed into the clear, jelly-like substance that fills the centre of your eye. If the amount of bleeding is small, you might see only a few dark spots (floaters). In more-severe cases, blood can fill the vitreous cavity and completely block your vision.

Vitreous haemorrhage by itself usually doesn’t cause permanent vision loss. The blood often clears from the eye within a few weeks or months. Unless your retina is damaged, your vision may return to its previous clarity.

• Retinal detachment.The abnormal blood vessels associated with diabetic retinopathy stimulate the growth of scar tissue, which can pull the retina away from the back of the eye. This may cause spots floating in your vision, flashes of light or severe vision loss.
• New blood vessels may grow in the front part of your eye and interfere with the normal flow of fluid out of the eye, causing pressure in the eye to build up (glaucoma). This pressure can damage the nerve that carries images from your eye to your brain (optic nerve).
• Eventually, diabetic retinopathy, glaucoma or both can lead to complete vision loss.

Prevention

You can’t always prevent diabetic retinopathy. However, regular eye exams, good control of your blood sugar and blood pressure, and early intervention for vision problems can help prevent severe vision loss.

If you have diabetes, reduce your risk of getting diabetic retinopathy by doing the following:

• Manage your diabetes.Make healthy eating and physical activity part of your daily routine. Try to get at least 150 minutes of moderate aerobic activity, such as walking, each week. Take oral diabetes medications or insulin as directed.
• Monitor your blood sugar level.You may need to check and record your blood sugar level several times a day — more-frequent measurements may be required if you’re ill or under stress. Ask your doctor how often you need to test your blood sugar.
• Ask your doctor about a glycosylated haemoglobin test.The glycosylated haemoglobin test, or haemoglobin A1C test, reflects your average blood sugar level for the two- to three-month period before the test. For most people, the A1C goal is to be under 7 percent.
• Keep your blood pressure and cholesterol under control. Eating healthy foods, exercising regularly and losing excess weight can help. Sometimes medication is needed, too.
• If you smoke or use other types of tobacco, ask your doctor to help you quit. Smoking increases your risk of various diabetes complications, including diabetic retinopathy.
• Pay attention to vision changes.Contact your eye doctor right away if you experience sudden vision changes or your vision becomes blurry, spotty or hazy.

Remember, diabetes doesn’t necessarily lead to vision loss. Taking an active role in diabetes management can go a long way toward preventing complications.

Diagnosis

Diabetic retinopathy is best diagnosed with a comprehensive dilated eye exam. For this exam, drops placed in your eyes widen (dilate) your pupils to allow your doctor to better view inside your eyes. The drops may cause your close vision to blur until they wear off, several hours later.

During the exam, your eye doctor will look for:

• Abnormal blood vessels
• Swelling, blood or fatty deposits in the retina
• Growth of new blood vessels and scar tissue
• Bleeding in the clear, jelly-like substance that fills the center of the eye (vitreous)
• Retinal detachment
• Abnormalities in your optic nerve

In addition, your eye doctor may:

• Test your vision
• Measure your eye pressure to test for glaucoma
• Look for evidence of cataracts

Tests

• Comprehensive Eye Exam– During your exam, your eye care professional dilates your eyes and evaluates your vision for several factors. If necessary, additional tests/procedures may be used to confirm your diagnosis.
• Fluorescein Angiography– This test helps your doctor see changes in the structure or function of your retinal blood vessels. To perform this test, your doctor injects a fluorescent yellow dye into a vein in your arm or hand, then photographs your retina as the dye outlines your blood vessels. Your doctor can use the images to pinpoint blood vessels that are closed, broken down or leaking fluid
• Indocyanine Green Angiography (ICG)– This test uses an injectable dye and special cameras to find blood circulation issues in the choroid. The choroid is a layer of blood vessels under the retina.
• Optical Coherence Tomography (OCT)– This imaging technique provides cross-sectional views of your retina. This helps your physician see if there is any abnormal swelling in your retina. The images of the retina show the thickness of the retina, which will help determine whether fluid has leaked into retinal tissue. Later, OCT exams can be used to monitor how treatment is working.
• Ultrasound Imaging– This safe, painless test uses high-frequency sound waves to produce detailed images of the inside of your eye. This helps your doctor identify retinal damage.

Treatment

Treatment, which depends largely on the type of diabetic retinopathy you have and how severe it is, is geared to slowing or stopping progression of the condition.

Early diabetic retinopathy

If you have mild or moderate nonproliferative diabetic retinopathy, you may not need treatment right away. However, your eye doctor will closely monitor your eyes to determine when you might need treatment.

Work with your diabetes doctor (endocrinologist) to determine if there are ways to improve your diabetes management. When diabetic retinopathy is mild or moderate, good blood sugar control can usually slow the progression.

Advanced diabetic retinopathy

If you have proliferative diabetic retinopathy or macular oedema, you’ll need prompt surgical treatment. Depending on the specific problems with your retina, options may include:

• This laser treatment, also known as focal laser treatment, can stop or slow the leakage of blood and fluid in the eye. During the procedure, leaks from abnormal blood vessels are treated with laser burns.

Focal laser treatment is usually done in your doctor’s office or eye clinic in a single session. If you had blurred vision from macular oedema before surgery, the treatment might not return your vision to normal, but it’s likely to reduce the chance the macular oedema may worsen.

• Panretinal photocoagulation.This laser treatment, also known as scatter laser treatment, can shrink the abnormal blood vessels. During the procedure, the areas of the retina away from the macula are treated with scattered laser burns. The burns cause the abnormal new blood vessels to shrink and scar.

It’s usually done in your doctor’s office or eye clinic in two or more sessions. Your vision will be blurry for about a day after the procedure. Some loss of peripheral vision or night vision after the procedure is possible.

• This procedure uses a tiny incision in your eye to remove blood from the middle of the eye (vitreous) as well as scar tissue that’s tugging on the retina. It’s done in a surgery centre or hospital using local or general anaesthesia.
• Injecting medicine into the eye.Your doctor may suggest injecting medication into the vitreous in the eye. These medications, called vascular endothelial growth factor (VEGF) inhibitors, may help stop growth of new blood vessels by blocking the effects of growth signals the body sends to generate new blood vessels.

Your doctor may recommend these medications, also called anti-VEGF therapy, as a stand-alone treatment or in combination with Panretinal photocoagulation. While studies of anti-VEGF therapy in the treatment of diabetic retinopathy are promising, this approach is not yet considered standard.

Surgery often slows or stops the progression of diabetic retinopathy, but it’s not a cure. Because diabetes is a lifelong condition, future retinal damage and vision loss are still possible.

Even after treatment for diabetic retinopathy, you’ll need regular eye exams. At some point, additional treatment may be recommended.

Alternative medicine

Several alternative therapies have suggested some benefits for people with diabetic retinopathy, but more research is needed to understand whether these treatments are effective and safe.

Be sure to let your doctor know if you are taking any herbs or supplements. They have the potential to interact with other medications, or cause complications in surgery, such as excessive bleeding.

It’s vital not to delay standard treatments to try unproven therapies. Early treatment is the best way to prevent vision loss.

Coping and support

The thought that you might lose your sight can be frightening, and you may benefit from talking to a therapist or finding a support group. Ask your doctor for referrals.

If you’ve already lost vision, ask your doctor about low-vision products, such as magnifiers, and services that can make daily living easier.