Diabetic Retinopathy

Diabetic retinopathy is a complication of diabetes caused by the weakening of blood vessels supplying the retina inside the eye. It is the leading cause of new blindness among adults in the United States.

The risk increases over time; about 60 percent of patients who have had diabetes for 15 years or more show some blood vessel damage in their eyes. The vessels may become enlarged, leak blood or fluid, or develop fragile brush-like branches called neovascularization. Juvenile diabetics--those who develop diabetes in childhood or adolescence--are especially prone to diabetic retinopathy at an early age.

Just why diabetes causes diabetic retinopathy is not completely understood; however, it is known that diabetes affects small blood vessels in various parts of the body, and the condition may be aggravated in diabetic patients by pregnancy or high blood pressure.

Types of Diabetic Retinopathy

There are two stages of the disease. Background retinopathy, considered an early stage of the condition, involves changes in the blood vessels within the retina. Some shrink, others grow to form balloon-like sacs, which obstruct blood flow and may leak or hemorrhage. In the majority of cases, sight is not seriously affected and the condition may not progress. However, background retinopathy is a warning sign and can lead to a more serious, sight-threatening condition. Leaking fluid may collect in the macula, the center portion of the retina, causing distortion and even loss of central vision.

The second form is called proliferative retinopathy. The fragile new blood vessels may rupture and bleed into the back of the eye, clouding the normally clear vitreous body and producing distorted images. Scar tissue from the ruptured blood vessels may tighten and pull on the retina, detaching it from the inner wall. Though there is no symptom of pain, severe loss of sight and even blindness may result.

Examination and Diagnosis

If you are diabetic, you need to be aware of the risks and have regular, professional eye examinations. Yearly eye exams are strongly recommended. If you show signs of retinal damage, your eyes may need to examined even more frequently. For non-diabetic patients, a comprehensive eye examination can alert your optometrist to the onset of diabetes even before you may be aware you have the condition.

A specialized microscope is used to examine the interior of the eye. If further and more precise evaluation is necessary, you will be referred to a specialist who will utilize a technique called fluorescein angiography, which involves rapid, computerized photography of the blood vessel system in the retina following injection of fluorescent dye.

Following examination, treatment is prescribed based on the patient's age, history, lifestyle, and the degree of damage observed. In some cases, careful monitoring is all that is required. In others, surgical or laser treatment is needed to halt progress of the disease and attempt to improve sight.

Modern Treatment

When diabetic retinopathy is detected early, photocoagulation by ophthalmic laser, an outpatient procedure, is typically used to arrest the damage. Small bursts of the laser's heat seal the leaking blood vessels and form tiny scars inside the eye. The scars reduce the growth of abnormal blood vessels and help bond the retina to the back of the eye.

If the vitreous body has become too clouded with blood, vitrectomy, or surgical removal of the vitreous, may be advised. The timing of this procedure will vary from one patient to another; in some instances, the vitreous may clear itself naturally.

What Results Can Be Expected?

Diabetes is a chronic condition and successful treatment for diabetic eye conditions depends greatly on the patient's willingness to participate fully in his or her care. In general, the greatest improvements in vision are experienced by patients who heed the early warning signs of diabetic retinopathy and scrupulously follow medical advice with respect to diet, exercise, and medication. The better control you have over your blood sugar level, the less damage will occur in your eyes--and in other parts of your body.