Nov 2, 2020

Diabetes and Vision Loss: Your Questions Answered

Diabetes is a metabolic disease that causes high blood sugar. Over time, diabetes can damage your eyes and cause different eye diseases, such as diabetic retinopathy, diabetic macular edema, glaucoma, and cataracts leading to poor vision or even blindness.

Common questions about diabetes and eye health

How does diabetes affect my eyes?

High blood glucose, also called blood sugar, damages blood vessels in the body including in the retina at the back of the eye. The retina is responsible for sensing light and creating light signals that your brain turns into images. Damaged blood vessels in the retina can leak fluid and can also encourage new blood vessels to grow which are unorganized and leaky. If not managed, this can cause scarring and high pressure in the eye, leading to vision loss.

What eye diseases are caused by diabetes?

There are four main eye diseases associated with diabetes:

  • Diabetic Retinopathy: This is when the retina is damaged by leaky blood vessels. It’s the most common cause of vision loss in people with diabetes. In early stages you may not have any symptoms, but if the disease isn’t caught in time blood vessels can continue to grow on the retina leading to vision loss.
  • Diabetic Macular Edema: This is when the macula, the small part of the retina that is responsible for central and detail vision swells. This can lead to vision loss or blindness and it usually develops in people who already have diabetic retinopathy.
  • Glaucoma: There are different types of glaucoma but all of them are caused by damage to the optic nerve, the nerve fibres that send light signals from the retina to the brain. Most cases of glaucoma are caused by high pressure in the eye and if untreated can lead to vision loss or blindness. A person with diabetes has double the chance of developing glaucoma as someone without diabetes.
  • Cataracts: Cataracts are caused by a clouding over of the lens, a part of the front of the eye that helps focus light onto the retina. This clouding can lead to blurring and vision loss. People with diabetes have about twice the chance of getting cataracts, although it isn’t clear how diabetes and high blood sugar cause this.
Image of four graphics, each displaying signs of vision loss in persons with no eye disease (far left), diabetic retinopathy (left), glaucoma (right), cataracts (far right)

Will I develop diabetic eye disease?

Anyone with diabetes can develop a diabetic eye disease and your risk goes up the longer you’ve had diabetes. Your chances of developing an eye disease increase if you have high blood sugar or blood pressure that isn’t treated.

If you already have diabetes, pregnancy can affect your eye health, and diabetic retinopathy often develops faster or gets worse during pregnancy. Get regular eye exams during your pregnancy to protect your vision. Diabetes that occurs only during pregnancy, called gestational diabetes, usually doesn’t impact your eye health.

How do I know if I have a diabetic eye disease?

There are often no symptoms at the early stages of diabetic retinopathy, glaucoma, or cataracts. That’s why it’s important to get regular eye exams because damage might be occurring without you noticing any change in your vision. Some symptoms of diabetic eye disease include:

  • Blurry or wavy vision
  • Dark areas or vision loss
  • Poor colour perception
  • Spots, also called floaters
  • Flashes of light
  • Eye pain

Call a doctor right away if you notice any sudden changes to your vision, including floaters or flashes of light.

If you have diabetes, it’s important to have an annual eye exam to diagnose any eye disease early. These eye exams are simple tests that are usually covered by provincial health insurance. During the test, your eye care provider will use eye drops to dilate your eyes so they can look at the back of your eye. They will also test your vision and eye pressure.

Can I protect my eyes and prevent vision loss?

The best ways to prevent vision loss from diabetes are to:

  • Manage your blood sugar, blood pressure, and cholesterol
  • Get help to quit smoking
  • Have regular eye exams

Managing diabetes reduces the risk of eye damage and testing regularly can help catch any problems early so that you can get the right treatments to prevent vision loss.

Are there treatments for diabetic eye diseases?

There are treatments for most diabetic eye diseases that may help slow down or even prevent vision loss. One of the first things you can do if you are diagnosed with a diabetic eye disease is to try and manage your diabetes, including your blood sugar to prevent further vision loss.

Depending on the type of eye disease you have and how far it has progressed, your eye care provider may suggest other treatment options, including medicines such as eye drops or injections, or surgeries such as laser treatment or cataract surgery.

Is there anything that can help me if I’ve already lost some vision?

If you have lost vision because of diabetes talk to your doctor or eye care provider. You may be referred to a low vision specialist or rehabilitation specialist who may recommend eyeglasses, adaptive technology devices, or mobility training to help you stay active.

This content was adapted from the NIH National Institute of Diabetes and Digestive and Kidney Diseases website.

Learn more

Access our Diabetic Retinopathy Resource page

Access our Glaucoma Resource page

Access our Cataracts Resource page

Check out this video for a brief description of diabetic retinopathy:

Share your voice

Living with diabetes and vision loss? Complete this survey to help tell policy makers what it’s like to live with vision loss and why it’s crucial that new treatments are made available and accessible to all Canadians.

Have an eye health related question? Contact FBC’s Health Information Line at 1.888.626.2995 or

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