Diabetic Eye Problems

Diabetes is a disease in which blood glucose, or blood sugar, is too high. Glucose comes from food, and the body's cells need it for energy. The hormone insulin helps glucose get into cells. In type 1 diabetes, the body does not make insulin; in type 2, it does not make or use insulin well. Without enough insulin, glucose builds up in the blood.

Over time, high blood glucose can damage the blood vessels and lenses of the eyes, leading to serious problems that can harm vision and sometimes cause blindness.

Common diabetic eye problems

• Diabetic retinopathy, the leading cause of blindness in American adults. It affects the blood vessels in the retina, the light-sensitive layer of tissue at the back of the eye, which can swell and leak fluid. Untreated, it can cause vision loss and retinal detachment, in which the retina is pulled away from its normal position.
• Diabetic macular edema (DME), when blood vessels in the retina leak fluid into the macula, the part of the retina needed for sharp, central vision. It usually develops in people who already have other signs of diabetic retinopathy.
• Glaucoma, a group of diseases that can damage the optic nerve, the bundle of nerves connecting the eye to the brain. In glaucoma caused by diabetes, damaged blood vessels at the front of the eye lead new vessels to grow near the iris, the colored part of the eye. They block the space where fluid drains out, so fluid builds up and pressure inside the eye rises.
• Cataract, the leading cause of blindness worldwide, when the clear lens at the front of the eye becomes cloudy. Cataracts are common with age, but people with diabetes tend to get them younger and faster. Researchers think high glucose causes deposits to build up in the lens.

Who is at higher risk

Anyone with diabetes can develop diabetic eye disease, but the risk is higher for people with diabetes who:

• have had diabetes for a long time;
• do not have good control of high blood glucose or high blood pressure;
• are pregnant;
• have high blood cholesterol;
• smoke tobacco.

Symptoms

In the early stages there are usually no symptoms, which is why regular dilated eye exams matter even if your eyes seem healthy.

Call your eye care professional right away if you notice:

• many new spots or dark wavy strings floating in your vision (floaters);
• flashes of light;
• a dark shadow, like a curtain, over part of your vision;
• vision loss;
• eye pain or redness.

Talk with your eye care professional about these, even if they come and go:

• spots or dark wavy strings floating in your vision;
• blurry or wavy vision;
• vision that changes a lot;
• trouble seeing colors.

Diagnosis and treatment

Eye care professionals diagnose eye problems with a dilated eye exam. Drops widen the pupils so the professional can look for signs of trouble and treat it before it harms vision. They also test vision and measure the pressure inside the eyes.

Treatment depends on the problem and how serious it is, and may include:

• lasers to stop blood vessels from leaking;
• injections in the eye to stop new, leaky blood vessels from growing;
• surgery to remove blood and scar tissue or to replace a cloudy lens;
• eye drops to lower the fluid pressure in the eye.

These treatments are not cures, and problems can come back. The best defense against serious vision loss is to take control of your diabetes, keep blood pressure and cholesterol in a healthy range, and get regular eye exams.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Diabetic Eye Problems." https://medlineplus.gov/diabeticeyeproblems.html
• MedlinePlus credits the information to the National Institute of Diabetes and Digestive and Kidney Diseases, NIH.