Diabetes Health Center

Diabetes and Eye Problems

Causes of Eye Problems in Those With Diabetes

In people with diabetes, high blood sugar damages the walls of the small blood vessels in the eye, altering their structure and function. As part of this condition, called diabetic retinopathy, these vessels may thicken, leak, develop clots, close off, or grow balloon-like defects called microaneurysms. Frequently, fluid accumulates in the part of the retina used in tasks such as reading; this condition is called macular edema. In advanced cases, the retina is robbed of its blood supply and grows new, but defective, vessels -- a process called neovascularization. These fragile vessels can bleed, creating vision-impairing hemorrhages, scar tissue, and separation of the retina from the back of the eye (retinal detachment). The new vessels can also block fluid flow within the eye, producing glaucoma.

Tests for Eye Problems in Diabetes

It's important that anyone who has diabetes gets annual eye exams from an ophthalmologist so that retinopathy can be detected early. When you visit an ophthalmologist, he or she will question you about your medical history and vision and will ask you to read an eye chart. The doctor will then directly examine the retina using an instrument called an ophthalmoscope.

Some of the features of diabetic retinopathy cannot be seen during a basic eye exam and require special exams. To get a better look at the inside of the eye, your doctor will use eye drops to dilate the pupils and will then view the retina with lenses and a special light called a slit lamp. A test called fluorescein angiography can reveal changes in the structure and function of the retinal blood vessels. For this test, the doctor injects a fluorescent yellow dye into one of your veins and then photographs your retina as the dye outlines the blood vessels.

Your eye exam will likely also include a check for glaucoma and cataracts, both of which occur more frequently in people with diabetes and can cause vision problems.

Treatment of Diabetic Retinopathy

If you have diabetes, treatment of retinopathy should involve both a medical doctor and an ophthalmologist. Your medical doctor can help you better control blood sugar and can treat other complications of diabetes that may worsen diabetic retinopathy, such as impaired kidney or heart function. Your ophthalmologist can directly treat retinopathy with a laser or a surgical procedure called vitrectomy, to prevent further vascular changes and preserve vision. Don't be surprised if your doctor recommends one of these treatments before you notice any vision problems: Before eye problems start is usually the best time for treatment.

Laser treatment for retinopathy, called laser photocoagulation, works in part by creating tiny, painless retinal burns that seal off leaking vessels and reduce swelling. The number of burns your doctor makes and the number of treatments you need depend on the type and extent of your retinopathy and how well it responds to treatment. You may have to wait several months to find out if this treatment is improving your condition.