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.
Diabetes is a leading cause of blindness in Canada. People with diabetes are more likely to develop cataracts at a younger age and are twice as likely to develop glaucoma, but diabetes’ effect on the retina is the main threat to vision.
This is why screening early and often is so important for those with diabetes.
Diabetic eye damage
Called diabetic retinopathy, this effect of diabetes on the eyes is the most common cause of blindness in people under age 65 and the most common cause of new blindness in North America. It is estimated that approximately 2 million individuals in Canada (i.e. almost all people with diagnosed diabetes) have some form of diabetic retinopathy.
What is retinopathy?
Diabetes may affect all blood vessels in your body, including those inside your eye. Diabetic retinopathy occurs when there is a weakening or swelling of the tiny blood vessels in the retina of your eye, resulting in blood leakage, the growth of new blood vessels and other changes. If diabetic retinopathy is left untreated, blindness can result.
Effect of retinopathy
The effect of retinopathy on vision in people with diabetes varies widely, depending on the stage of the disease. Common symptoms can include blurred vision (often linked to blood glucose levels), flashes or sudden loss of vision. However, diabetes may cause other eye symptoms.
Fluid can leak into the center of the macula, the part of the eye where clear, detailed vision occurs. The fluid swells the macula and blurs the vision. Called macular edema, it can occur at any stage, although it is more likely to occur as the disease progresses. About one-half of people with proliferative retinopathy also have macular edema.
How is diabetic retinopathy treated?
In the early stages, diabetic retinopathy is monitored through eye health examinations. No treatment is needed for nonproliferative retinopathy, unless there is macular edema. Recommended treatment for those with proliferative or severe nonproliferative retinopathy, vitreous hemorrhage or macular edema, is laser therapy, which helps to shrink the abnormal blood vessels, and/or vitrectomy.
Can vision loss from diabetes be prevented?
Yes, in a routine eye examination, your doctor of optometry can diagnose potential vision threatening changes in your eye that may be treated to prevent blindness. However, once damage has occurred, the effects can be permanent. It is important to control your diabetes as much as possible to minimize your risk of developing retinopathy.
How do I know if I have retinopathy?
In early stages there may be no symptoms. Which is why it is vital to have regular eye exams. Symptoms, if present, can include:
- Blurred vision
- Flashes of light in the field of vision
- Sudden loss of vision
- Blotches or spots in vision
Who should be screened for retinopathy?
Anyone with diabetes! Individuals with diabetes (both type 1 and type 2) are at risk for diabetic retinopathy. People who have diabetes should be screened annually. As well as:
- Any individual older than 15 with type 1 diabetes should be screened annually beginning five years after the onset of diabetes.
- All individuals with type 2 diabetes should be screened at the time of diagnosis and every year after.
- Women with type 1 or type 2 diabetes or women who hope to become pregnant should be screened before conception, during the first trimester, as needed during pregnancy and within the first year post-partum and every year after.
How do I see an optometrist/eye doctor?
Anyone can see an optometrist; referrals from your family doctor are NOT required. There are many online resources to locate an optometrist. You can check out opto.ca to find an optometrist near you. You can also look in the phone book or ask your family doctor.
What is the cost?
In Ontario, for people living with diabetes, the cost of an eye exam by an optometrist or ophthalmologist is covered through OHIP. Should your optometrist feel more extensive diagnostic tests are needed for a comprehensive exam there may be a fee associated with those tests - as they are not covered by OHIP. However, if you choose, those tests can be performed by an ophthalmologist. Ophthalmologist fees for additional diagnostic tests are covered by OHIP.
Other informative resources:
- Canadian Diabetes Association
- Eye Connect: Diabetic Retinopathy from the CNIB
- Eye Health and Diabetes from the Government of Ontario
- Guidelines for the Collaborative Management of Persons with Diabetes Mellitus by Eye Health Council of Ontario