Diabetic Macular Edema

Diabetic macular edema (DME) is a common complication of diabetic retinopathy (DR). DME is caused by damage to the blood vessels of the retina and is a leading cause of vision loss in the working-age population in the developed world.

When the blood vessels in the retina swell and leak, the leaking fluid can cause swelling in the macula, the central part of the retina at the back of the eye where sharp vision is determined. Macular edema – the swelling of the macula – can then result in blurred vision and can lead to permanent vision loss over time.

While DME can occur at any stage of diabetic retinopathy, DME is more likely to occur as the disease progresses.

It is estimated that vision impairment resulting from DME affects approximately 2.5% of the nearly 2.4 million Canadians with diabetes, or approximately 60,000 Canadians, making it a major cause of adult-onset vision loss.

Medical diagram of the human eye

Caption: Medical diagram of the human eye, highlighting the location of the iris, cornea, pupil, lens, vitreous gel, optic nerve, macula, fovea, and retina.


The first symptoms of DME are usually blurry vision and/or “floaters,” spots in the line of vision. Sometimes vision will clear without treatment and then symptoms will reoccur. Treatment should therefore be sought at the first sign of vision difficulties.

Visual impairment due to DME compromises patients’ ability to perform activities such as working, reading and driving and can lead to blindness.

CNIB partnered with Novartis Pharmaceuticals Inc. to raise awareness of the impact of DME. The campaign, called "Worth a thousand words: Preserve your vision," features this unique photo album of images​ that have been digitally altered to appear as they might be seen by someone living with DME or age-related macular degeneration (AMD). 

Risk Factors

While everyone with diabetes is at risk of developing DME, the progression of diabetic retinopathy can be assisted by controlling blood sugar (glucose) levels, blood pressure and blood cholesterol levels.

People with either Type 1 or Type 2 diabetes are at risk of developing diabetic retinopathy. Obesity and smoking are important risk factors for developing Type 2 diabetes. To protect against vision loss, everyone with diabetes should get a dilated eye exam once a year.

Diagnosis and Treatment

Treatment options are available that, particularly if the condition is discovered early, can prevent or slow down the progression of vision loss and in some cases improve vision.​

Getting more help

In addition to this web resource, CNIB provides vital rehabilitation services in communities across Canada, helping people with various types and levels of vision loss build the skills and confidence to lead full, active lives. Whether you’re looking to connect with others who have sight loss, looking for ways to stay active and independent, require more information about monitoring and maintaining your vision health, we can help.

The link below also provides more information