Diabetes and Vision: How High Blood Sugar Affects Eyesight

How can you tell if diabetes is affecting your eyes

If you have diabetes, then you know how difficult it can be to keep up with all the variables involved. Everything you do, from general health to eating to exercising, all serve to help keep your blood sugar in check. Failure to do so can harm organs like your heart and kidneys, as well as nerves.

High blood sugar also has an effect on your eyesight. When it comes to diabetes and vision, you want to understand how diabetes affects your vision and be aware of your risk of diabetic eye diseases such as diabetic retinopathy and glaucoma. You also want to make sure that you’re visiting your ophthalmologist for annual comprehensive eye exams.

To understand how high blood sugar affects eyesight, we need to look at:

  • Diabetes and vision
  • Diabetic eye disease
  • Diagnosis and treatment

General health requires a lot more attention and effort if you have diabetes. Being aware of the danger that diabetes poses to your eyesight can motivate you to be more proactive in your overall health.

Diabetes and Vision

Diabetes inhibits your body’s capacity to effectively use or make insulin in order to control blood sugar (glucose) levels. High blood sugar levels can result in damage to several different parts of your body. This includes your:

  • Heart
  • Blood vessels
  • Kidneys

Along with these vital parts of your body, high blood sugar levels can also damage your eyes in a number of ways. This can include damaging the tiny blood vessels in your eyes and fluid accumulating on the retina. If left undiagnosed or untreated, you can experience irreparable damage to your vision or even blindness. 

Luckily for diabetics, around 90% of vision loss due to diabetes can be prevented if detected early. The problem is that 60% of diabetics aren’t getting the right kind of eye exams. Early detection is paramount if you want to prevent diabetes-related blindness. However, you need to make sure that you’re getting the right kind of exam or else you run the risk of developing diabetic eye disease.

Diabetic Eye Disease

Diabetic eye disease is not the name of an actual disease. Instead, it’s an umbrella term for a group of diabetes-related diseases that affect your vision. Diabetic eye disease includes:

  • Diabetic retinopathy
  • Cataracts
  • Diabetic macular edema
  • Glaucoma

It usually takes between 5 to 10 years to develop a diabetic eye disease. However, that doesn’t mean that you’re in the clear before then. Uncontrolled blood sugar can result in eye damage long before symptoms appear, and diabetic eye disease can result in severe sight loss or even blindness at any stage.

Diabetic Retinopathy

High blood sugar can cause serious damage to blood vessels throughout your body. Diabetic retinopathy is when diabetes-related damage occurs in the blood vessels of your eyes. This condition most often affects the retina, which lines the back of your eyes and detects light. 

Retinal damage can include:

  • Swelling
  • Leaking
  • Completely closing up
  • The growth of abnormal blood vessels on the retina

Diabetic retinopathy comes in two types: non-proliferative retinopathy (aka background diabetic retinopathy) and proliferative diabetic retinopathy. Non-proliferative retinopathy occurs when blood vessels in the retina rupture, putting you at risk of serious vision loss. 

Proliferative retinopathy occurs when your body attempts to replace the damaged blood vessels to prevent blood loss. This condition is less common than non-proliferative retinopathy, but it’s also more likely to cause impaired vision or even vision loss.

Diabetic Macular Edema

Diabetes and blurred vision often go hand in hand. One cause of blurred vision for diabetics is diabetic macular edema (DME), which is when fluids accumulate on the retina resulting in swelling and blurred vision. DME is actually the result of non-proliferative retinopathy. In this case, it specifically affects the macula, which is the center of the retina. 

Non-proliferative retinopathy doesn’t usually result in major vision loss. With that said, DME is one of the biggest threats to your vision if you’re diabetic. Make sure that you’re seeing your ophthalmologist regularly and getting the correct exams to check for DME.


Cataracts occur when the eye’s crystalline lens becomes clouded. This lens is located directly behind the pupil and helps the cornea direct light to the retina. There are multiple causes for cataracts, including aging, injury, and genetics just to name a few. In the case of diabetes, cataracts are the result of excess blood sugar.

The main symptoms of cataracts are dim or blurred vision which manifests as a constant filminess or glare when exposed to bright light. Keep in mind that you don’t need severely reduced vision to have a cataract. Any clouding of the lens is considered a cataract regardless of its severity.


Like diabetic eye disease, glaucoma is actually a term for a group of diseases. Glaucoma gradually impairs the eye’s optic nerve, which is what connects your eye to your brain. Symptoms of glaucoma include:

  • Poor night vision
  • Diminished peripheral vision
  • Frequent mild headaches
  • Redness in one or both eyes
  • Blurred vision
  • Eye pain

You can develop glaucoma at any age, though people over the age of 40 are at the highest risk. It’s estimated that around 150 million people have undiagnosed glaucoma. Diabetics are twice as likely to develop glaucoma than non-diabetics, so it’s extremely important that you get regular eye exams to catch it before it gets worse.

Diagnosis and Treatment

Vision loss is the key symptom of diabetic eye disease. Other symptoms can’t be diagnosed until vision loss has occurred, which is why it’s so important to have your eyes checked regularly. The best way to ensure this is to get an annual comprehensive eye exam. 

Comprehensive eye exams allow ophthalmologists to check for:

  • Changes in the lens of your eye
  • Changes in blood vessels
  • Nerve tissue damage
  • Changes to the macula

Early detection is essential when it comes to diabetic eye disease. It will allow for timely treatment and the crucial follow-up care that you need to protect yourself from vision loss. For the best defense, diabetics should be taking their medications as prescribed, eating healthy, and exercising.

Baptist Eye Surgeons is an ophthalmological practice in Knoxville, TN, and Morristown, TN. Visit our website to meet our doctors and learn more about our specialties, or give us a call at 865-579-3920 for more information or to schedule an appointment.

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