diabetic retinopathy is a leading cause of blindness and a disease that is on the rise due to an increase in diabetes and an aging population.

Approximately 12 percent of new cases of blindness are caused by diabetic retinopathy. In fact, people with this eye disease are 25 to 29 times more likely than the general population to become blind within four years.

The longer you have diabetes and the less controlled your blood sugar is — the more likely you are to develop diabetic retinopathy. This condition is one in which glucose sticks to the tiny blood vessels that nourish the retina, weakening them and possibly causing them to bleed or leak fluid, distorting vision. “We want to get on top of things because once sugar sticks  it doesn’t unstick — once you get rust underneath your car, you can never get rid of it,” says Dr. Peter Lin, who contributed to the 2013 Canadian Diabetes Association (CDA) Clinical Practice Guidelines.

Nearly all patients with type 1 diabetes and 60 percent of those with type 2 diabetes develop some form of diabetic retinopathy in the first 20 years after the onset of diabetes. An estimated 2.4 million Canadians had diabetes in 2008, a number expected to grow to 3.7 million by 2018/19.

Although controlling blood sugar and blood pressure significantly lowers the risk for retinopathy to develop and progress, you can’t reverse the damage. Still, “if you eat healthy, exercise, and get your sugars down — you’ve just reduced future damage tremendously,” says Dr. Lin.

How diabetic retinopathy develops

In its early stages, known as nonproliferative retinopathy, the blood vessels in the retina — which acts like a film projector in the back of your eye, projecting images to your brain — begin to leak. With proliferative retinopathy, new abnormal blood vessels replace the old ones, then break and leak blood into the retina and into the center cavity of the eye, causing floaters.

Sometimes the leaking fluid swells the macula (the part of your retina that helps you to see colour), causing diabetic macular edema (DME). “Although DME most commonly causes reduced vision, severe proliferative disease is the condition that can cause complete blindness,” says ophthalmologist Dr. Phil Hooper, a lead author on the Canadian Ophthalmological Society’s Diabetic Retinopathy Guidelines.

"In Canada, only 32 percent of patients with type 2 diabetes meet the CDA guideline-recommended schedule of evaluation for diabetic retinopathy."

Screening is crucial

Dr. Hooper points out that people would only know they had the condition if they had central DME or proliferative retinopathy. “Otherwise, the disease can be quite advanced, yet the person is unaware there is a problem.” To detect diabetic retinopathy early, a regular eye examination that includes a dilated retinal exam by someone trained to recognize diabetic eye disease, namely an optometrist or ophthalmologist is recommended. In some cases, this screening examination may be accompanied by retinal photography, which captures an image of the back of the eye, and may provide a future reference to compare with during follow-up visits.  CDA guidelines recommend screenings take place annually for type 1 diabetes, upon diagnosis of diabetes, and then every one to two years for type 2.  In Canada, only 32 percent of patients with type 2 diabetes meet the CDA guideline-recommended schedule of evaluation for diabetic retinopathy.

No treatment is needed for nonproliferative retinopathy, unless macular edema is present, while laser therapy is used with proliferative or severe nonproliferative retinopathy. If a hemorrhage has led to lost vision, vitrectomy surgery can restore vision. Most cases of DME are treated with injections of medication into the eye.

“In the past, doctors may not have focused on the eye as much for diabetes because they were more afraid of heart attacks and strokes, which are much higher in numbers in people with

type 2 diabetes,” says Dr. Lin, who notes that the aging population means we are seeing more eye disease in Canadians who have diabetes.  “Our goal [now] is that diabetics never suffer from eye disease, kidney disease, heart disease, or stroke.”

Presented by the International Federation on Ageing - Feature Supported by Bayer