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How Diabetes Can Damage Your Vision

by Michael Healy
diabetes and your vision

According to the American Diabetes Association, diabetes is the leading cause of vision loss in adults aged 18-64.

Contributing to a number of serious eye issues, including diabetic retinopathy, macular edema, cataracts, and glaucoma, diabetes slowly causes damage to your vision and can ultimately lead to blindness.

Fortunately, research has shown that managing your diabetes and getting regular eye exams are very effective in preventing vision loss and protecting your eyesight.

What is diabetes?

Diabetes is a group of diseases that affects how your body uses blood glucose (also known as blood sugar). Glucose is the main source of energy for your body and your brain. 

Glucose requires a hormone called insulin to be able to get from your blood into your cells so it can be used for energy. In the case of diabetes, the body isn’t able to produce enough insulin—or isn’t able to use insulin effectively—meaning glucose stays in your blood.

Over time, high levels of blood sugar can lead to a number of progressive and serious health issues, including increased risk of heart attack or stroke, kidney disease, nerve damage, circulation issues, and a number of different eye diseases.

Currently, the National Institute of Health estimates that over 34 million Americans have diabetes. An additional 88 million, or 35% of, U.S. adults have prediabetes, or elevated blood sugar levels that put them at more of a risk for developing diabetes.

Diabetes related eye disease

While high blood glucose levels are not likely to damage vision in the short term, they can cause increased pressure, changing fluid levels, or swelling in the eyes. When left untreated, high blood glucose levels slowly damage the blood vessels in the eyes. While damage to the blood vessels in the eyes begins during prediabetes, it often takes years to progress to the point where the condition becomes symptomatic and develops into one of the following eye diseases.

Diabetic retinopathy

Diabetic retinopathy is the most common cause of diabetes-related eye health and blindness. The condition develops when high glucose levels cause damage to the blood vessels in the retina (the cells in the back of the eye responsible for sensing light and sending images to the brain).

As these blood vessels start to swell, blood flow is reduced and vision can become progressively blurry. This condition, known as nonproliferative retinopathy, is the most common form of diabetic retinopathy and often progresses through three stages: mild, moderate, and severe.

In some people, retinopathy can develop into a more severe form known as proliferative retinopathy. Proliferative retinopathy occurs when blood vessels become so damaged that they totally close off and blood is unable to flow through them. As a result, the body grows new blood vessels in the retina. However, these new blood vessels are much weaker, often leak blood into the retina, and contribute to the development of scar tissue – all of which affect your ability to see and lead to more serious problems.

Diabetic retinopathy usually affects both eyes.

Macular edema

Often developing as a result of nonproliferative retinopathy, macular edema is swelling in the macula, the area of the retina responsible for detailed vision required for things like reading, driving, and other activities that require seeing fine details.

Characterized by blurry or wavy vision at the center of your field of vision that ranges from mild distraction to total vision loss, diabetes-related macular edema requires immediate attention and can be treated to stop and, in some cases, reverse vision loss.


Similar to the damage caused to blood vessels in the retina and macula, diabetes-related swelling and damaged blood vessels in between the eyeball and the cornea (the clear outer layer at the front of your eye that helps to focus light so you can see clearly) contributes to the cataracts in people with diabetes.

The Centers for Disease Control (CDC) estimates that over 30% of diabetic adults over age 45 also have cataracts.


People with diabetes are twice as likely to develop glaucoma, a disease that gradually increases pressure on the optic nerve and can lead to loss of vision and blindness if not treated early.

While doctors are still unsure of the exact cause of diabetes-related glaucoma, there is a strong indication that increasing amounts of the fluid in the eyes (known as aqueous humor) is unable to flow out of the eye—primarily as a result of damaged blood vessels. This buildup of aqueous humor increases pressure within the eye and specifically on the optic nerve, resulting in loss of vision.

Diabetes-related glaucoma typically affects both eyes but can be more noticeable in one eye than the other.

Warning signs of diabetes-related vision issues

Obviously, being diagnosed with diabetes is the leading warning sign associated with developing a diabetes-related vision issue. However, of the over 125 million Americans living with diabetes or prediabetes, less than 25% have been diagnosed with a type of diabetes. 

Since diabetes-related eye issues start to develop when people are prediabetic and rarely become noticeable until much later, it’s important to be aware of the main signs and symptoms associated with these eye diseases.

The main signs and symptoms of diabetes-related eye disease can include:

  • Blurred, wavy, or cloudy vision
  • Spots, holes, or floaters in a person’s vision
  • Reduced intensity of colors/yellowing of vision
  • Increased sensitivity to light
  • Noticing a halo of light around lights
  • Poor night vision
  • Vision changes that require stronger eyeglass prescription

Preventing or slowing diabetes-related eye issues

Although diabetes has no official cure, there are several steps that are essential for managing your diabetes and staying healthy, these include:

  • Keeping blood glucose levels within normal ranges
  • Managing blood pressure and cholesterol levels
  • Maintaining a healthy weight
  • Eating a heart healthy diet
  • Exercising on a regular basis
  • Taking medicine as prescribed

Additionally, while eye problems tend to be more common in people who have diabetes, early detection, and early treatment have proven to be very effective in treating and preventing diabetes-related vision loss. In fact, getting an annual eye exam can prevent 95% of diabetes-related vision loss.

Remember, your eye doctor is the only doctor who can diagnose the eye diseases mentioned above—and the earlier they are discovered, the more effective treatment will be.

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