Condition Basics

What is diabetic retinopathy?

Diabetes can damage the small blood vessels in part of your eye. This part of the eye is called the retina. It detects light that enters the eye. Then it sends signals to your brain about what the eye sees.

When this type of eye damage happens, it's called diabetic retinopathy. It can lead to poor vision and even blindness.

What causes it?

Diabetes damages small blood vessels throughout the body. Diabetic retinopathy happens when high blood sugar damages the blood vessels of the retina. This is the part of the eye that sends images to your brain. Keeping your blood sugar in your target range lowers your risk of getting diabetic retinopathy.

What are the symptoms?

There are usually no symptoms of diabetic retinopathy until it starts to change your vision. When this happens, the disease is already severe. Changes in vision can be a sign of severe damage to your eye. These changes can include floaters, pain in the eye, blurry vision, or new vision loss.

How is it diagnosed?

An eye exam by an eye specialist (ophthalmologist or optometrist) is the only way to find diabetic retinopathy. Having a dilated eye exam regularly can help find retinopathy before it changes your vision. On your own, you may not notice symptoms until the disease is severe.

How is diabetic retinopathy treated?

Treatment can't cure diabetic retinopathy. But laser treatment, medicine, or surgery often works very well to prevent, delay, or reduce vision loss. You may need to be treated more than once as the disease gets worse. Keeping your blood sugar in your target range is always important and will help prevent retinopathy from getting worse.

Symptoms

There are usually no symptoms of diabetic retinopathy until it starts to change your vision. When this happens, the disease is already severe. Having your eyes checked regularly can find the disease early enough to treat it. Treatment can help prevent vision loss.

Symptoms of diabetic retinopathy and its complications may include:

• Blurred or distorted vision or trouble reading.
• Floaters or spots in your vision.
• Partial or total loss of vision. Or you might have a shadow or veil across your field of vision.
• Pain, pressure, or constant redness of the eye.

What Happens

Diabetic retinopathy can lead to poor vision and even blindness. Most of the time, it gets worse over many years.

At first, the blood vessels in the eye get weak. This can lead to blood and other liquid leaking into the retina from the blood vessels. This is called non-proliferative retinopathy. And this is the most common retinopathy. If the fluid leaks into the centre of your eye, you may have blurry vision. Most people with non-proliferative retinopathy have no symptoms.

If blood sugar levels stay high, diabetic retinopathy will keep getting worse. New blood vessels grow on the retina. This may sound good, but these new blood vessels are weak. They can break open very easily, even while you are sleeping. If they break open, blood can leak into the middle part of your eye in front of the retina and change your vision. This bleeding can also cause scar tissue to form. The scar tissue can pull on the retina and cause the retina to move away from the wall of the eye (retinal detachment). This is called proliferative retinopathy. Sometimes people don't have symptoms until it's too late to treat them. That's why having eye exams regularly is so important.

Retinopathy can also cause swelling of the macula of the eye. This is called macular edema. The macula is the middle of the retina, which lets you see details. When it swells, it can make your vision much worse. It can even cause blindness.

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When to Call a Doctor

Call your doctor now if you have diabetes and notice:

• New or sudden vision changes.
• Floaters in your field of vision. Floaters often appear as dark specks, globs, strings, or dots. A sudden shower of floaters may be a sign of a retinal detachment, which is a serious complication of diabetic retinopathy.
• A new visual defect, shadow, or curtain across part of your vision. This is another sign of retinal detachment.
• Eye pain or a feeling of pressure in your eye.
• New or sudden vision loss. Sudden partial or complete vision loss is a symptom of many disorders that can occur within or outside the eye, including retinal detachment or bleeding within the eye. Sudden vision loss is always a medical emergency.

Call your doctor for an appointment if:

• You have more and more trouble doing everyday tasks (like driving or reading) because of your eyesight.

Watchful waiting

Watchful waiting is not okay if you have diabetes and notice changes in your vision.

If you have type 2 diabetes, even if you don't have any symptoms of eye disease, you still need to have your eyes and vision checked regularly by an eye specialist (ophthalmologist or optometrist). If you wait until you have symptoms, it's more likely that complications and severe damage to the retina will have already happened. These may be harder to treat. You could end up with permanent vision loss.

If you have type 1 diabetes, are age 10 or older, and were diagnosed 5 or more years ago, you should have your eyes checked even if you don't have symptoms. If you wait until you have symptoms, it's more likely that complications and severe damage to the retina will have happened. These may be harder to treat. And the damage may be permanent.

Watchful waiting is not an option if you already have diabetic retinopathy but don't have symptoms or vision loss. You will need to go back to your ophthalmologist for frequent checkups (every few months in some cases) so that your doctor can closely monitor changes in your eyes. There is no cure for the disease. But treatment can slow its progression. Your ophthalmologist can tell you how often you need to be checked.

Exams and Tests

Diabetic retinopathy can be found during a dilated eye exam. This exam is done by an ophthalmologist or optometrist. An exam by your primary doctor, when your eyes aren't dilated, isn't the same. You need a full exam done by an ophthalmologist or optometrist.

Eye exams for people with diabetes can include:

• Visual acuity testing. This measures how well your eye can focus. It also checks how well you can see details at near and far distances.
• Ophthalmoscopy and slit lamp exam. These may be used to find clouding of the lens (cataract), changes in the retina, and other problems.
• Tonometry. This test measures the pressure inside the eye. It is used to help find glaucoma.

Regular dilated eye exams can help find eye diseases early. And they can prevent or delay vision loss.

Screening for diabetic retinopathy

If diabetic retinopathy hasn't been diagnosed, Diabetes Canada recommends that:

• People with type 1 diabetes who are age 15 and older should have a dilated eye exam within 5 years after diabetes is diagnosed. Then they should be tested every year. ^{footnote 1}
• People with type 2 diabetes should have an exam as soon as diabetes is diagnosed. Then they should be tested every year. ^{footnote 1}
• People who have type 1 or type 2 diabetes and who are planning to become pregnant should have an exam before they get pregnant, if they can. They should have an exam once during the first 3 months (first trimester) of pregnancy and within the first year after the baby is born. ^{footnote 2}

If your eye exam results are normal, you may need fewer follow-up exams.

People who are pregnant and have gestational diabetes aren't at risk for diabetic retinopathy. They don't need to be screened for it.

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Treatment Overview

You may need treatment for diabetic retinopathy if:

• It has affected the centre (macula) of the retina.
• Abnormal new blood vessels have started to appear. (This is called proliferative retinopathy.)
• Your side (peripheral) vision has been severely damaged.

There is no cure for diabetic retinopathy. But treatment works very well to prevent, delay, or reduce vision loss. The sooner the condition is found, the easier it is to treat. And it's more likely that vision will be saved.

Controlling your blood sugar levels is always important. This is true even if you've been treated for diabetic retinopathy and your eyes are better. In fact, good blood sugar control is even more important in this case. It can help keep retinopathy from getting worse.

Treatment options

Treatment options include:

Laser treatment (photocoagulation).

• Laser treatment usually works very well to prevent vision loss if it's done before the retina has been severely damaged. It may also help with macular edema.
• Severe proliferative retinopathy may be treated with a more aggressive laser therapy called scatter (pan-retinal) photocoagulation. It allows your doctor to limit the growth of new blood vessels across the back of your retina. Laser treatments may not always work in treating proliferative retinopathy.

Anti-VEGF (vascular endothelial growth factor) or an anti-inflammatory medicine.

Anti-VEGF medicines slow the growth of abnormal blood vessels in the retina. This growth is triggered by a protein called vascular endothelial growth factor (VEGF). Anti-VEGF medicines block the effects of VEGF.

• Sometimes injections of these types of medicine help to shrink new blood vessels in proliferative diabetic retinopathy.
• An anti-VEGF medicine, such as aflibercept or ranibizumab, might be used if the macula has been damaged by macular edema.
• Steroids may be injected into the eye. Sometimes an implant, such as Iluvien, may be placed in the eye. The implant releases a small amount of corticosteroid over time.

Surgical removal of the vitreous gel (vitrectomy).

• This surgery may help improve vision if the retina hasn't been severely damaged. It's done when there is bleeding (vitreous hemorrhage) or retinal detachment. These two problems are rare in people with early-stage retinopathy.
• This surgery is also done when severe scar tissue has formed. It can be used to treat macular edema.

Many people with diabetic retinopathy need to be treated more than once as the condition gets worse.

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Self-Care

Taking care of yourself

• Have regular eye exams. Tell your doctor about any changes in your vision.
• Keep blood sugar in your target range.
  • Eat a variety of healthy foods, and follow your meal plan so you know how much carbohydrate you need for meals and snacks.
  • It's important to stay as active as you can. Walking is a good choice. Bit by bit, increase the amount you walk every day. Try for at least 2½ hours of moderate to vigorous activity each week.
  • Be safe with medicines. Take your medicine exactly as prescribed. Call your doctor if you think you are having a problem with your medicine.
  • Check your blood sugar as often as your doctor recommends.
• Eat a low-salt diet. If you have high blood pressure, this may help lower it. You may also need to take medicines to reach your goals.
• Do not smoke. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
• Avoid risky activities. These include things like weight lifting and some contact sports. They may trigger bleeding in the eye through impact or increased pressure.
• Talk to your doctor if you are pregnant or planning to get pregnant. Retinopathy can get much worse during pregnancy. Planning ahead with your doctor and following the doctor's instructions can decrease this risk.

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