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How High Blood Sugar Can Damage Your Eyes

How High Blood Sugar Can Damage Your Eyes

In 2018, about 34.2 million Americans — 10.5% of the population — had been diagnosed with diabetes, according to the Centers for Disease Control and Prevention (CDC). The disease is characterized by high blood sugar levels, either because the body can’t produce enough of the hormone insulin to move the sugar from the blood into the cells, where it’s used for energy (Type 1), or the cells have become resistant to insulin’s effects (Type 2).

Type 2 is the most preventable form, as well as the most common, including about 90-95% of cases. Risk factors for developing Type 2 include a poor diet and a sedentary lifestyle.

At Retina Specialists, our team of expert ophthalmologists regularly performs diabetic eye exams to evaluate, diagnose, and treat diabetes complications that affect the eyes.

If you have diabetes or are at risk for developing it, here’s how elevated blood sugar can damage your eyes and why diabetic eye exams are so important.

How high blood sugar can damage your eyes

High sugar levels can lead to serious complications that can rob you of sight if not treated. Diabetic retinopathy is a major cause of blindness, affecting more than one in four American adults living with diabetes.

It begins when supporting blood vessels start leaking into the tissue of the retina, the light-sensitive tissue at the back of your eye. These can cause the macula, the central 2% of the retinal tissue that provides your clear central vision, to swell (macular edema). That can lead to blurred vision, especially in your central vision.

As the disease progresses, vessels start to close themselves off, starving the macula of oxygen and other nutrients. To compensate for the deficiencies, new vessels grow rapidly on the retina’s surface, leading to scar tissue, a detached retina, and/or loss of sight.

Glaucoma is a collection of eye disorders that damage the optic nerve. High blood sugar interferes with the eye’s drainage system; the fluid pressure inside your eye increases until it leads to nerve damage. Glaucoma is a sneaky disease — it usually doesn’t produce any symptoms until there’s significant damage to the tissues. That’s why scheduling routine eye exams is so important; caught early enough, the damage can be prevented.

What to ask at your next diabetic eye exam

When you come into Retina Specialists for your yearly diabetic eye exam, your ophthalmologist evaluates both your visual acuity (how nearsighted or farsighted you are) and your eye health, paying particular attention to the structures that diabetes typically damages. 

These exams are a good time to learn more about how diabetes affects your eyes and what you can do to prevent complications. Some good questions to ask are:

What is my intraocular pressure (IOP)?

They may use an air puff test, a penlike tonometer that rests against the cornea, or an automated device, but the ophthalmologist always checks your IOP. That’s because increasing pressure stemming from improper drainage is an early sign of glaucoma.

Normal levels are considered 12-21 mgHg (millimeters of mercury), and your IOP can vary from one visit to the next, or even one day to the next. Anything over 21 is considered high, and the doctor will probably start you on pressure-lowering drops to prevent damage to the eye. Knowing your numbers can keep your eyes safe.

Do my retina and optic nerve look normal?

The doctor dilates your eyes for your exam to allow them to see all the internal structures, including all the way at the back of the eye. Since diabetes may damage both the retina and the optic nerve, you want to make sure they’re still healthy.

Are there lifestyle changes I can make to help protect my eyes?

As we’ve said, Type 2 diabetes is preventable, and most of that prevention comes from your lifestyle choices. Your doctor will have a unique view on the relationship between the disease and your eyes, so getting their opinion on how to prevent problems is a good idea.

If you’re a diabetic but haven’t had a comprehensive eye exam in more than a year, it’s time to come into Retina Specialists so we can do a thorough checkup. Call us at any of our five Texas offices — in Dallas, DeSoto, Plano, Mesquite, and Waxahachie.


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