Diabetes and the Eyes

If you have diabetes, your blood glucose, or blood sugar, levels are too high. Over time, this can damage your eyes. The most common problem is diabetic retinopathy. It is a leading cause of blindness in adults.

Your retina is the light-sensitive tissue at the back of your eye. You need a healthy retina to see clearly. Diabetic retinopathy damages the tiny blood vessels inside your retina.

Diabetes is a disease that affects the body’s ability to produce or use insulin effectively to control blood sugar (glucose) levels. Although glucose is an important source of energy for the body’s cells, too much glucose in the blood for a long time can cause damage in many parts of the body, including the heart, kidneys, blood vessels and the small blood vessels in the eyes.

You may not notice it at first. Symptoms can include:

• Blurry or double vision
• Rings, flashing lights, or blank spots
• Dark or floating spots

• Pain or pressure in one or both of your eyes
• Trouble seeing things out of the corners of your eyes

Treatment often includes laser treatment or surgery, with follow-up care. Two other eye problems can happen to people with diabetes. A cataract is a cloud over the lens of your eye. Surgery helps you see clearly again. Glaucoma happens when pressure builds up in the eye, damaging the main nerve. Eye drops or surgery can help.

Diabetic Retinopathy

When the blood vessels in the eye’s retina (the light sensitive tissue lining the back of the eye) swell, leak or close off completely — or if abnormal new blood vessels grow on the surface of the retina — it is called diabetic retinopathy.

Symptoms of diabetic retinopathy can include:

• Blurry vision or double vision
• Flashing lights, which can indicate a retinal detachment
• A veil, cloud, or streaks of red in the field of vision, or dark or floating spots in one or both eyes, which can indicate bleeding
• Blind or blank spots in the field of vision
• Fluctuating vision in response to changing blood glucose levels; vision can change from day to day, or from morning to evening.
• Blurred central vision from macular edema can interfere with reading.
• Decreased visual acuity can interfere with seeing the markings on an insulin syringe or the display on a standard blood glucose monitor.
• Irregular patches of vision loss or ‘blind spots’ can make it difficult to judge the size of food portions on a plate.
• Decreased depth perception, in combination with decreased visual acuity, can make it difficult to see curbs and steps, or walk to the diabetes clinic.

People who are at greater risk of developing diabetic retinopathy are those who have diabetes or poor blood sugar control, women who are pregnant, and people with high blood pressure, high blood lipids or both.