Let’s cut to the chase. High blood sugar levels can cause permanent damage to your eyesight—putting you at higher risk for blurry vision, cataracts, glaucoma, retinopathy and other eye-related issues. Perhaps the scariest blood sugar vision statistic comes from the World Health Organization (WHO)—close to 1 million people are blind due to diabetes.

High blood sugar levels are the calling card of diabetes and pre-diabetes. Recent statistics estimate that 463 million people across the globe are living with diabetes and that statistic is projected to climb to 700 million by 2045.

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As if that isn’t frightening enough, here in the United States, the Centers for Disease Control and Prevention (CDC) claims that about 1 in 10 Americans have diabetes, with approximately 1 in 5 people unaware that they even have the disease. Add to that fact this one: the CDC advises that another 96 million American adults (38%) have prediabetes, including 26.4 million aged 65 or older.

Let’s face facts. When it comes to your eyesight, high blood sugar levels are problematic. Fortunately, there are preventative steps you can take, and the first step is figuring out what your blood sugar levels are, so you can learn how to properly manage them.


How Can Blood Sugar Affect Vision?

The answer to that question is in all kinds of ways—and none of those ways are good.

Identifying blood sugar levels—and following up with blood sugar management, as needed—starts with one of two kinds of tests; and if you’re diabetic, your doctor may recommend a combination of the two as part of ongoing management of high blood glucose levels.

The first is a fasting blood sugar (or glucose) blood test that identifies your current glucose level. Results are normal at 99 mg/dL or below.

The second test is an A1c blood sugar (glucose) test, sometimes known as an HbA1c test, which does not require fasting and measures the amount of sugar in your blood as an average over the past three months. For those reasons, many experts find that this test demonstrates a more accurate reading of how your body metabolizes glucose over time. A normal (or healthy) A1c level is below 5.7%. Prediabetes is identified at 5.7% to 6.4% and turns into diabetes once your blood glucose reaches 6.5%.

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Most eye issues related to blood sugar are often the result of the long-term damage caused by high glucose levels, so some of these issues are often related specifically to diabetes (and pre-diabetes). As we mentioned earlier, a large number of people who have high blood sugar levels don’t know it. (Yes, that’s another reason to get your glucose levels tested.)

Although the answer to the question “how can blood sugar affect vision” is far from a love letter, still, let us count the ways. Here are five eye problems that are associated with blood sugar issues.

  1. Blurry Vision—If you’re not seeing things clearly, this can be the result not only of high sugar levels, but it also could indicate low or fluctuating glucose levels, especially if you already have diabetes. It could be a matter of getting those fluctuations properly addressed so your glucose levels can be reduced and returned back to a healthier range. Blurry vision may actually be one of the first hints that you have a blood sugar problem, giving you a chance to better manage the issue. Don’t ignore this symptom, don’t try to self-diagnose, and don’t wait. Go see an eye doctor who can help you figure out the problem, likely with a dilated eye exam. Your blurry vision, while still potentially serious, might not actually be related to blood sugar. Find out! Read more here.
  1. Cataracts—Your eyes have an internal lens that acts as a camera, allowing you to focus on an image and see properly. Cataracts distort your vision, making things look foggy or filmy or cloudy. More than 50% of Americans over 65 have cataracts. But there is also a strong link between unmanaged high blood sugar levels and cataracts. Left untreated over time, high glucose levels damage the tiny blood vessels in the back of your eyes, causing the lens to swell and the enzymes in the lens to convert glucose into excessive sorbitol, which in turn creates that cloudy vision. People with diabetes tend to get cataracts earlier and those cataracts can progress more quickly. Surgery to remove cataracts—and replace the damaged lens with a healthy artificial one—is the way to reverse the problem. However, if your blood sugar is not under control, your doctor may not want to proceed with this surgery as it can cause complications in healing and increase the risk of infections.
  1. Glaucoma—This chronic and progressive eye disease is a result of damage to the optic nerve, with loss of vision first impacting the edges of your visual field and moving toward your central vision over time. If you catch the problem in time, prescription eye drops may be able to stop glaucoma from progressing. However, if you don’t, the loss of vision cannot be reversed. There are numerous factors that can cause glaucoma, and high sugar blood levels over time is just one of them. High sugar levels can wreak havoc with the retina’s blood vessels and result in new abnormal ones which can cause an increase in eye pressure, thus leading to glaucoma. People with diabetes are twice as likely to develop glaucoma compared to those without diabetes, says the Glaucoma Research Foundation. Dilated eye exams which allow your eye doctor to check your eye pressures and optic nerve should be conducted at least once a year and a field of vision test is also something to be considered. More info here.
  1. Diabetic Retinopathy—The retina is the lining found at the back of your eye. A healthy retina senses light and translates that into signals that your brain uses for you to see. Retinopathy occurs when the small blood vessels in your retina are damaged, in the case of diabetic retinopathy as a result of high blood glucose levels. When this disease first starts, you may or may not experience symptoms, which is why having regular dilated eye exams is so important, especially if you are having trouble managing your blood sugar levels. But with this condition, the beginning is not like the end. When ignored, diabetic retinopathy can lead to glaucoma, retinal detachment, and even blindness if poorly managed. This article and this one explain that early intervention can help you prevent severe eye problems later on.
  1. Diabetic Macular Edema—Some research has shown that diabetes is a risk factor for developing age-related macular degeneration (AMD), an eye disease that can result in severe central vision loss. Diabetic macular edema, however, is a specific complication of diabetic retinopathy. The macula is the part of your retina responsible for helping you read, drive and recognize faces. Unmanaged high glucose levels can result in swelling in the macula and over time diabetic macular edema can result in partial vision loss or even blindness. Learn more about diabetes-related eye problems here.


What Can You Do to Protect Your Eyesight from Blood Sugar Issues?

Whether you have or haven’t yet gotten to the point where your blood sugar is high or your vision is being negatively impacted because your blood sugar has reached a problematic level, there are things that you can do to reduce your risk of serious eye problems related to high blood glucose levels.

Here are three to start:

  1. Schedule regular eye exams. Your eye doctor can recommend how often you should put those exams on your schedule, but likely it’s no less than once a year—especially if you’re having blood sugar vision (that’s slang for the eye problems we’ve been discussing), and possibly twice a year if you’re having vision troubles. Among other things, your doctor should conduct a dilated eye exam, which will allow him or her to check for common eye problems like the ones we’ve just discussed.
  2. Test your blood sugar levels. It’s just good practice to test your blood sugar levels at least twice a year—four times if you’re having problems that would require closer monitoring of those levels. And here’s why: your blood sugar levels go up and down depending, in part, on your dietary habits and exercise routine. While in an ideal world, you would consistently be working to keep your blood sugar levels in check, sometimes you need a proverbial kick in the pants to remind you that overindulging in simple carbs or eating ice cream every night are not the best habits. Your doctor can order an A1c blood test or you can self-test at home. For example, at OmegaQuant, we now offer simple HbA1c finger-prick blood test to help you manage your blood glucose levels. Learn more here.
  3. Improve your diet. Once you know the results of your HbA1c levels, from there you’ll know whether you need to take steps to help lower or maintain (or in less common circumstances, increase) your blood sugar levels. Engaging in healthy dietary habits is one of the core components of achieving—and maintaining—healthy blood sugar levels. And, a healthy, well-balanced, nutrient-rich diet, combined with regular exercise can also help you maintain a healthy weight. All of these are important for avoiding blood sugar eye-related problems and protecting your vision for the long-term.

This article offers a few additional tips to help prevent diabetes-related eye problems. For example, the author advises that it’s not just your blood sugar that you may need to lower, but also your blood pressure and cholesterol. You should also protect your eyes from the sun’s harmful rays by wearing sunglasses; and because smoking can damage your blood vessels, stop (and certainly don’t start) smoking.

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These statements have not been evaluated by the Food and Drug Administration. This test is not intended to diagnose, treat, cure, prevent or mitigate any disease. This site does not offer medical advice, and nothing contained herein is intended to establish a doctor/patient relationship. OmegaQuant, LLC is regulated under the Clinical Laboratory improvement Amendments of 1988 (CLIA) and is qualified to perform high complexity clinical testing. The performance characteristics of this test were determined by OmegaQuant, LLC. It has not been cleared or approved by the U.S. Food and Drug Administration.

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