Eye Problems Caused by Diabetes

Reviewed by: HU Medical Review Board | Last reviewed: March 2021.

Type 2 diabetes is a condition that is caused by high blood glucose (sugar). Both type 1 and type 2 diabetes may lead to a group of vision problems called diabetic eye disease. Over time, diabetes can damage the internal structures that allow you to see, leading to poor vision or even blindness.

The most common long-term eye-related complications of diabetes include:1-4

  • Cataracts
  • Glaucoma
  • Diabetic retinopathy
  • Dry eye disease
  • Macular edema

How does diabetes affect the eyes?

Diabetes affects the eyes in several ways. Sometimes the vision changes are temporary, but gradually, high blood glucose creates long-term changes to the tissues of the eye.

For instance, high blood glucose can cause swelling in the eye or change fluid levels in the short-term, which can cause blurry vision. This type of vision problem is usually temporary and goes away as blood glucose becomes normal.

When blood glucose stays high for a long time, it begins to damage the tiny blood vessels in the back of the eye. This can lead to higher pressure inside the eye, swelling, scarring, and leaking fluid in the eye.

People who have untreated high blood glucose and high blood pressure are more likely to develop diabetic eye diseases. Having high blood cholesterol and smoking increase the risk even more. The longer you have diabetes, even if it is treated, the more likely you are to develop vision problems.1

What are cataracts?

The front part of the eye, the lens, gives us sharp vision, when working properly. However, sometimes the lens gets cloudy, making it harder to see detail. Cloudy lenses are called cataracts. People with diabetes are more likely to develop cataracts and develop cataracts at younger ages than people without diabetes.1

What is glaucoma?

People with diabetes are 2 times more likely to develop glaucoma than those without diabetes. Glaucoma is an eye disease that damages the optic nerve, which is like a “cable” that connects the eye to the brain. Glaucoma can lead to gradual vision loss and is the second leading cause of blindness worldwide. There are often no early symptoms or warning signs of glaucoma. It is treated with eye drops.2

What is diabetic retinopathy?

The retina is the inner lining of the back of the eye. It senses light and connects to the optic nerve to send signals to the brain, which is how you see. Diabetes damages the blood vessels that feed the retina, causing a condition known as diabetic retinopathy. About 1 in 3 people with diabetes who are 40 and older have at least some signs of diabetic retinopathy. Diabetic retinopathy is the leading cause of blindness in adults in the United States.1,2

What is dry eye disease?

Dry eye disease is just like it sounds. The surface of the eye becomes dry, and this can lead to vision problems. Up to half of those with diabetes develop chronic dry eye. People with diabetes, glaucoma, and peripheral neuropathy are more likely to also have dry eye disease.4

What is diabetic macular edema?

Macular edema is another vision problem related to the retina. The part of the retina (at the back of the eye) that helps you see faces is called the macula. When diabetes damages the delicate blood vessels of the macula, it destroys sharp vision. Macular edema most often develops in people who have diabetic retinopathy.1

Signs of diabetic eye disease

Many times, there are no warning signs that vision loss and other eye problems are developing. That is why it is so important to get a dilated eye exam at least once a year when you have diabetes. If you notice any of these changes, see a doctor as quickly as possible if you hace:1

  • Blurry or wavy vision or flashes
  • Frequent vision changes
  • Dark areas or vision loss
  • Problems distinguishing colors
  • Floaters (spots or dark strings that float across your vision)

If you change your diabetes medicines or care plan, you may have blurry vision for a few days or weeks. This type of blurry vision tends to go away as your blood glucose gets closer to normal.1

Treating eye disease quickly

The good news is that diabetic eye problems may often be slowed or prevented altogether. The best ways to keep your eyes healthy are:1

  • Manage your blood glucose, high blood pressure, and cholesterol levels
  • Get regular dilated eye exams
  • See an optometrist or ophthalmologist quickly if you notice any sudden vision changes
  • Quit smoking

Early, regular treatment can prevent or greatly delay vision loss and blindness.1

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