Eye problems and diabetes introduction
If you have diabetes, regular visits to your ophthalmologist for eye exams are important to avoid eye problems. High blood sugar (glucose) increases the risk of diabetes eye problems. In fact, diabetes is the leading cause of blindness in adults age 20 to 74.
If you have eye problems and diabetes, don't buy a new pair of glasses as soon as you notice you have blurred vision. It could just be a temporary eye problem that develops rapidly with diabetes and is caused by high blood sugar levels.
High blood sugar in diabetes causes the lens of the eye to swell, which changes your ability to see. To correct this kind of eye problem, you need to get your blood sugar back into the target range (90-130 milligrams per deciliter or mg/dL before meals, and less than 180 mg/dL one to two hours after a meal). It may take as long as three months after your blood sugar is well controlled for your vision to fully get back to normal.
Blurred vision can also be a symptom of more serious eye problem with diabetes. The three major eye problems that people with diabetes may develop and should be aware of are cataracts, glaucoma, and retinopathy.
Cataracts and Diabetes
A cataract is a clouding or fogging of the normally clear lens of the eye. The lens is what allows us to see and focus on an image just like a camera. Although anyone can get cataracts, people with diabetes get these eye problems at an earlier age than most and the condition progresses more rapidly than in people without diabetes.
If you have a cataract, there is a cloudy area in the lens of your eye that results in the inability to focus light, and your vision is impaired. Symptoms of this eye problem in diabetes include blurred or glared vision.
During cataract surgery, the cloudy lens is removed or cleaned out and replaced by a clear man-made lens.
Glaucoma and Diabetes
When fluid inside the eye does not drain properly from a buildup of pressure inside the eye, it results in another eye problem with diabetes called glaucoma. The pressure damages nerves and the vessels in the eye, causing changes in vision.
Treatment of open-angle glaucoma -- the most common form of glaucoma -- requires lowering the eye's pressure by increasing the drainage of aqueous humor or decreasing the production of the fluid. Medications can accomplish both of these goals.
With open-angle glaucoma, there may be no symptoms of this eye problem at all until the disease is very advanced and there is significant vision loss. In the less common form of this eye problem, symptoms can include headaches, eye aches or pain, blurred vision, watering eyes, halos around lights, and loss of vision.
Treatment of this eye problem in diabetes can include special eye drops, laser procedures, medicine, or surgery. Surgery and laser treatments are directed at improving the eye's aqueous drainage. You can prevent serious eye problems in diabetes problems by getting an annual glaucoma screening from your eye doctor.
Diabetic retinopathy is one of the vascular (blood-vessel related) complications related to diabetes. This diabetes eye problem is due to damage of small vessels and is called a "microvascular complication." Kidney disease and nerve damage due to diabetes are also microvascular complications. Large blood vessel damage (also called macrovascular complications) includes complications like heart disease and stroke.
The microvascular complications have, in numerous studies, been shown to be related to high blood sugar levels. You can reduce your risk of these eye problems in diabetes complications by improving your blood sugar control.
Diabetic retinopathy is the leading cause of irreversible blindness in industrialized nations. The duration of diabetes is the single most important risk for developing retinopathy. So the longer you have diabetes, the greater the risk of this very serious eye problem. If retinopathy is not found early or is not treated, it can lead to blindness.
People with type 1 diabetes rarely develop retinopathy before puberty. In adults with type 1 diabetes, it is also rare to see retinopathy before five years' duration of diabetes. The risks of retinal damage increase with progressive duration of diabetes. Intensive control of blood sugar levels will reduce your risks of developing retinopathy. The DCCT, a large study of people with type 1 diabetes showed that people with diabetes who achieved tight control of their blood sugars with either an insulin pump or multiple daily injections of insulin were 50%-75% less likely to develop retinopathy, nephropathy (kidney disease), or nerve damage (all microvascular complications).
People with type 2 diabetes usually have signs of eye problems when diabetes is diagnosed. In this case, control of blood sugar, blood pressure, and blood cholesterol with diabetes have an important role in slowing the progression of retinopathy and other eye problems.
Types of Retinopathy in Diabetes:
- Background retinopathy. Sometimes the blood vessel damage exists, but there is no vision problem. This is called background retinopathy. It's important to carefully manage your diabetes at this stage to prevent background retinopathy from progressing to more serious eye disease.
- Maculopathy. In maculopathy, the person has developed damage in a critical area called the macula. Because this occurs in an area that is critical to vision, this type of eye problem can significantly reduce vision.
- Proliferative retinopathy. New blood vessels start to grow in the back of the eye. Because retinopathy is a microvascular complication of diabetes, a disease of small vessels, this type of retinopathy develops because of an increasing lack of oxygen to the eye from vascular disease. Vessels in the eye are thinned and occluded and they start to remodel.
Here, it is important to address the risks factors that can worsen the occluded vessels. Smoking cessation, high blood pressure control, cholesterol management, and blood sugar control must take place in order to stop the progression of new vessels from forming into the orbit of the eye. These are fragile vessels that can bleed and eventually cause a clot to form in the orbit, which scars and causes detachment of the retina. This eventually leads to irreversible vision loss.
Treatment of diabetic retinopathy may involve laser procedures or surgery. In a study of people with diabetes with early retinopathy, laser therapy to burn the fragile vessel resulted in a 50% reduction of blindness.
To prevent retinopathy with diabetes, have your eye doctor screen your eyes annually. Women with diabetes who later become pregnant should have a comprehensive eye exam during the first trimester and close follow-up with an eye doctor during the rest of their pregnancy to avoid serious eye problems with diabetes. (This recommendation does not apply to women who develop gestational diabetes, since they are not at risk for retinopathy.)
Preventing Eye Problems With Diabetes
The American Diabetes Association offers these eye care guidelines for people with diabetes to help prevent eye problems:
- People with type 1 diabetes should have a dilated eye exam by an ophthalmologist or optometrist within three to five years after diagnosis.
- People with type 2 diabetes should have a dilated eye exam by an ophthalmologist or optometrist shortly after diagnosis.
- Annual eye exams should be done with both type 1 and type 2 diabetes by an ophthalmologist or optometrist; more frequently if necessary.
- When considering pregnancy, women with a history of diabetes should have an eye exam prior and during pregnancy. This does not pertain to women with gestational diabetes.
To prevent eye problems in diabetes, you should:
- Control your blood sugar
- Control high blood pressure
American Diabetes Association: "Eye Disease."
American Diabetes Association: "Mental Heatlh Problem Linked to Diabetes."
Centers for Disease Control and Prevention: "Take Charge of Your Diabetes."
Colucciello, M. Arch Ophthalmol 2005; 123:1273. Hernandez, C. Diabetes Care, 2006; 29:2028.
Reviewed by Brunilda Nazario, MD on May 18, 2012
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