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How High Blood Sugar Impacts The Eyes and Vision

If you have diabetes, it is important to understand the connection between high blood sugar and your eyes. Diabetes and high blood sugar levels can cause many different health problems that show up in the body. Unfortunately, this includes a person’s vision and eye health. 

High blood glucose levels can cause significant damage to the tiny blood vessels in the back of the eyes. These blood vessels can start to get impacted even for people with prediabetes, who aren’t diagnosed with diabetes yet. This damage can lead to fluid leaking from blood vessels and swelling. 

Millions of people around the globe have diabetes and need to manage their health properly to avoid serious health problems. Some examples of health complications include the need to amputate limbs, kidney problems, and even blindness. You may be surprised to learn that diabetes is the main cause of blindness in adults between the ages of 20 and 74. 


Glaucoma is one of the main causes of irreversible blindness. It happens when the optic nerve starts to degrade faster than usual, due to an abnormally high amount of pressure. Our optic nerve carries important information from our eyes to the brain. 

Unfortunately, diabetic eye disease can increase the likelihood of someone developing glaucoma. If you have had diabetes for a long time you are more likely to get affected. Older people and those with poorly managed blood sugar levels or high blood pressure are at an even higher risk. 

For people with diabetic eye disease, negative changes in blood glucose levels eventually lead to weakened and damaged blood vessels in the retina. These changes can eventually lead to the development of glaucoma. 

Blurry Vision 


Diabetes can also lead to blurry vision if blood sugar levels are not properly managed. High blood sugar can cause the lens of the eye to swell up and make it harder to see clearly. Getting blood sugar back into a healthy range can help fix blurry vision. 

This can be anywhere from 70 mg/dL to 130 mg/dL before eating a meal and less than 180 mg/dL an hour or two after starting a meal. It’s always a good idea to ask your doctor what your ideal range should be instead of relying on general averages. 

Blurry vision could also be a sign of something more serious. For this reason, it’s important to contact your eye doctor immediately when experiencing blurry vision. 


As you can see, there are plenty of good reasons to manage your blood sugar levels well. Doing so can help you avoid a host of health problems that come with diabetes, including those that affect your eyes and vision. Protecting the eyes can be possible by living a healthy lifestyle that reduces the harmful health problems that come with diabetes. 

If you are an adult with type 1 diabetes, it is recommended to have a full dilated eye exam within five years of getting diagnosed. For adults with type 2 diabetes, a complete eye exam soon after diagnosis is recommended. For those that are pregnant or planning to become pregnant, a dilated eye exam is also a good idea.