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Blurry Vision and Beyond

How Diabetes Can Affect Your Eyes
By Dr. Shantan Reddy

Ideally, your fasting blood glucose (sugar) level should be between 70-99 mg/dL. If your blood sugar levels are between 100 – 125 mg/dL, you are in the prediabetic range and if your blood sugar reaches 126mg/dL, you are considered to be diabetic. This chronic condition is becoming more and more common. In fact, according to the CDC, nearly one in every three American adults is pre-diabetic. Whether you are considered prediabetic, or have diabetes, you are at an increased risk of developing other health conditions including heart disease, kidney disease or stroke. When blood sugar levels remain uncontrolled, it can also affect the health of your eyes causing blurry vision, cataracts, glaucoma, diabetic retinopathy or macular edema to develop, and in some cases, can even lead to blindness.  

While diabetes is a serious disease, your blood sugar can be controlled with medications, following a balanced diet, maintaining a healthy weight and staying active. Keeping your blood sugar levels within the recommended range, along with regular checkups with your primary care physician and an ophthalmologist, can reduce your risk of developing other complications. Board-certified ophthalmologist, Shantan Reddy, MD, shares how diabetes can affect your vision and provides tips to maintain good eye health.

Blurry Vision

Blurry vision is often one of the first signs you may have higher-than-normal blood sugar and/or diabetes. When your blood sugar level is elevated, it can cause the lenses of your eyes to swell, impacting your ability to see clearly. If you notice changes in your vision consult with an ophthalmologist who will perform a dilated eye exam to determine the cause. If the blurred vision is caused by high blood sugar, it’s important to get your blood sugar within the recommended range to prevent further damage. Once your blood sugar is under control it can take up to three months for your vision to return to normal.

Macular Edema

Macular edema is the most common eye condition linked to diabetes. Elevated blood sugar can weaken the blood vessels in your eyes. Over time they may begin to leak or grow abnormally. When this happens, fluid starts to accumulate in your macula, which is responsible for the majority of your vision. This causes the retina to swell, preventing the macula from functioning normally. In some cases, you may not have any symptoms initially, while for others, you may experience blurred vision or notice that colors appear dull or washed out. In order to prevent long-term, serious damage to your eyes and vision, it is important to have your eyes examined right away if you experience these symptoms. If macular edema is identified, a retina specialist can get you started on a treatment plan which can include injectable medications, laser or surgical procedures.


Your retina is made up of a group of cells located at the back of your eye and is an essential part of your vision. It works to absorb light entering the eye and turns it into images that your optic nerve sends to your brain. 

Elevated blood sugar levels can damage the small blood vessels in your retina leading to a condition called diabetic retinopathy. The longer your blood sugar remains elevated, the more likely you are to develop retinopathy. If left untreated, retinopathy can cause long-term damage to your eyes, including blindness.

Closely monitoring and keeping your blood pressure, blood sugar and cholesterol under control can help prevent diabetic retinopathy, or slow its progression.


Your eye is comprised of many intricate parts that work together so that you can see. The internal lens of your eye is what allows you to focus on objects. If the lens becomes cloudy, cataracts can develop which prevents your eye from focusing normally. This clouding can lead to symptoms such as blurred vision and glare. Anyone can develop a cataract, although they are more common with age. Individuals with diabetes are at an increased risk, and may get them earlier. If your blood sugar remains elevated, cataract symptoms are likely to worsen. Cataracts are normally treated with surgery, removing the cloudy lens and replacing it with an artificial one.


Glaucoma occurs when fluid within your eye is unable to drain properly, causing pressure to build up. This increased pressure can damage the blood vessels and nerves in your eyes which affect your vision. Glaucoma can develop in anyone, however, your risk is almost double if you are diabetic.

Some forms of glaucoma, or when it is in its earlier stages, may not cause any noticeable symptoms. If it is left undetected or untreated, it will worsen and lead to a variety of symptoms including blurred vision or vision loss. If you develop glaucoma, medications can be prescribed to lower your eye pressure and assist with drainage, while in some cases, surgery may be recommended.

If you are diabetic, you should closely monitor your eye health by completing a comprehensive eye exam each year which includes measuring your eye pressure.


While having diabetes or prediabetes can increase your chances of developing other conditions including those that affect your vision and eye health, working with your primary care physician to monitor and control your blood sugar can help prevent many serious complications. Staying up-to-date on your annual physicals can help to uncover underlying health concerns including elevated blood sugar levels, so that you can begin treatment before they progress. 

The average adult over the age of 40 should receive a comprehensive eye exam with an ophthalmologist every one to two years. If you have diabetes, yearly or more frequent eye exams may be recommended to more closely monitor your eye health. If you experience symptoms including blurred vision, black spots, flashes of light or floaters, it is considered emergent and you should be seen by an ophthalmologist right away.

For more information on our team of ophthalmologists, or to schedule a comprehensive eye exam, visit dupagemedicalgroup.com/services/ophthalmology/ or call 630-322-8300.

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