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Types of diabetic eye problems

"Diabetic eye" is written on a sheet of paper with a stethoscope lying on top.

Individuals with diabetes, whether it’s Type 1 or Type 2, are well aware of how blood sugar can affect your health and body function. One of the most common effects diabetes has is on your eyes and vision.

Eye problems from diabetes can include:

Below, we talk more about each of these effects diabetes can have on your eyes, plus which symptoms to look out for.

Diabetes and eyes

While the different types of diabetes can be differentiated by how much insulin the body produces (Type 1 produces no insulin while Type 2 produces very little), both types cause high blood sugar. The high levels of sugar damage blood vessels that are responsible for taking oxygen-rich blood from the heart and lungs to other tissues in the body.

Diabetes can damage the small blood vessels in the eye that nourish the retina — the thin, light-sensitive membrane in the back of the eye. Considering how crucial the retina is to vision, having it affected by damaged blood vessels leads to several diabetic eye issues.

Blurred vision

Blurred vision is typically one of the first diabetic eye symptoms experienced. Fortunately, the symptom is temporary and can be reversed by controlling your blood sugar levels.

Prolonged changes to blood glucose (sugar) levels can cause the lens inside the eye to become swollen, leading to blurry vision.

Depending on the degree of the blurry vision due to lens swelling, you may need a temporary change to your eyeglasses prescription to see clearly until your vision returns to normal.

Once blood glucose levels are well controlled, it can take up to six weeks for the lens changes to resolve and your vision (and refractive error) to return to normal. 

SEE RELATED: Diabetes and blurred vision

Diabetic retinopathy

Diabetic retinopathy is a diabetic eye disease that occurs when blood vessels in the retina swell, leak fluid or bleed due to damage done by high blood sugar levels. It’s also possible for new, abnormal blood vessels to grow in the eye due to diabetes, or for existing blood vessels to close off and make it impossible for blood to get to the retina.

While early stages of diabetic retinopathy may not cause obvious symptoms, it’s important that any changes in vision be addressed by scheduling an eye exam. If left untreated, diabetic retinopathy can cause permanent vision loss.

Symptoms of diabetic retinopathy include:

  • Blurred vision

  • Vision that becomes blurry, then suddenly returns to clear

  • Sudden appearance of or considerable increase in eye floaters

  • Poor night vision

  • Blank spots or dark shadows in your field of vision

The longer you have diabetes, the more likely your chances are of experiencing diabetic retinopathy. Similarly, the longer symptoms go untreated, the more serious they become. 

Annual eye exams make it possible to catch symptoms of diabetic retinopathy and establish treatment early.

Glaucoma

If you have diabetes, your risk of developing glaucoma is twice that of non-diabetics, according to the Glaucoma Research Foundation

Glaucoma is a potentially blinding eye disease that’s usually caused by increased pressure inside the eye.

As previously mentioned, diabetes can cause the growth of abnormal blood vessels inside the eye. These blood vessels are fragile and can leak easily. 

If abnormal blood vessels grow in the anterior part of the eye near the iris, they can block the structure through which fluid (that’s continually produced inside the eye) must drain to maintain normal eye pressure. When this occurs, pressure inside the eye increases, potentially causing glaucoma and vision loss. 

SEE RELATED: Are you at risk for diabetic eye disease?

Macular edema

Diabetes and diabetic retinopathy can cause a condition called macular edema.

The condition is characterized by fluid collecting in the macula — the part of the retina that provides our most detailed vision. This collection of fluid is caused by leaking blood vessels, which result from diabetic retinopathy.

The primary symptom of diabetic macular edema is painless blurry vision. 

Prolonged or severe macular edema from diabetes can result in permanent loss of visual acuity.

Cataracts

Cataracts are the most common diabetic eye problem. 

According to the National Institute of Health, people with diabetes are up to five times more likely to develop cataracts than non-diabetics, and cataracts tend to occur earlier in life if you have diabetes. 

Symptoms of diabetic cataracts include:

  • Blurry vision

  • Seeing halos around lights

  • Increased glare

  • Slightly reduced color vision

It appears that diabetes increases the risk of oxidative and osmotic (fluid balance) changes in the lens of the eye that result in cataract formation.

Keep up with routine eye exams

If you are diabetic or are at risk of diabetes, it’s critical to have a yearly eye exam so your eye doctor can check on the health of your eyes. 

All of the diabetic eye problems listed above can be avoided by controlling your blood sugar and by having routine eye exams to ensure your eyes remain as healthy as possible.

READ MORE: Diabetic eye exam: What it is and when you should have one

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Gary Heiting, OD

Gary Heiting, OD, is a former senior editor of AllAboutVision.com. Dr. Heiting has more than 30 years of experience as an eye care provider, health educator and consultant to the eyewear ... Read more