Diabetes and your vision

The current number of people living with diabetes in Canada is approximately 3.3 million. Type 2 diabetes is the most common form of the disease, accounting for 90% of cases. The prevalence of type 2 diabetes is increasing dramatically with current estimates confidently predicting a doubling of cases by 2025.

What is diabetes?

Diabetes is a chronic disease that prevents your body from making or using insulin, which in turn leads to increased sugar levels in your bloodstream, known as high blood sugar.

How does diabetes affect the eye?

Diabetes and its complications can affect many parts of the eye. Diabetes can cause changes in nearsightedness, farsightedness and premature presbyopia (the inability to focus on close objects). It can result in cataracts, glaucoma, paralysis of the nerves that control the eye muscles or pupil, and decreased corneal sensitivity.

Visual symptoms of diabetes include fluctuating or blurring of vision, occasional double vision, loss of visual field, and flashes and floaters within the eyes. Sometimes these early signs of diabetes are first detected in a thorough examination performed by a doctor of optometry. The most serious eye problem associated with diabetes is diabetic retinopathy.

What is retinopathy?

Over time diabetes can cause changes in the retina. Diabetic retinopathy occurs when there is a weakening or swelling of the tiny blood vessels that feed the retina of your eye, resulting in blood leakage, the growth of new blood vessels and other changes. When retinopathy advances, the decreased circulation of the blood vessels deprives areas of the retina of oxygen. Blood vessels become blocked or closed, and parts of the retina die. New, abnormal, blood vessels grow to replace the old ones.  If diabetic retinopathy is left untreated, blindness can result.

Can vision loss from diabetes be prevented?

Yes, in a routine eye examination, your optometrist can diagnose potential vision threatening changes in your eye that may be treated to prevent blindness. However, once damage has occurred, the effects are usually permanent. It is important to control your diabetes as much as possible to minimize your risk of developing retinopathy.

How is diabetic retinopathy treated?

In the early stages, diabetic retinopathy is monitored through eye health examinations. If necessary, it may be treated with intraocular injections of anti-VEGF therapy (Lucentis, Avastin) or laser therapy. A bright beam of light is focused on the retina, causing a laser burn that seals off leaking blood vessels. In other cases, retinal surgery may be necessary. Early detection of diabetic retinopathy is crucial, as treatment is much more likely to be successful at an early stage.

Are there risk factors for developing diabetic retinopathy?

Several factors that increase the risk of developing diabetic retinopathy include smoking, high blood pressure, drinking alcohol and pregnancy.

How can diabetes-related eye problems be prevented?

Monitor and maintain control of your diabetes. See your physician regularly and follow instructions about diet, exercise and medication. See your doctor of optometry for a thorough eye examination when you are first diagnosed with diabetes, at least annually thereafter and more frequently if recommended.