Q: Many of my patients with diabetes are concerned about blindness as a complication. What can I share with them?

Retinopathy is the primary cause of blindness in working adults and the most frequent microvascular complication in diabetes. This complication is strongly related to the duration of diabetes. Poor glucose control and hypertension also contribute to this risk. Other risk factors include gender (male), diabetic nephropathy, puberty, smoking, and dyslipidemia and pregnancy. It is important to note that the presence of retinopathy doubles the risk of cardiovascular disease.

Early identification can delay progression, and because there are no symptoms in the early stages, screening by an ophthalmologist or optometrist familiar with retinopathy is recommended. Patients with type 1 diabetes mellitus (DM) should have an initial dilated eye exam 5 years after diagnosis. Patients with type 2 DM should be examined at diagnosis. Pregnant women should have an exam in the first trimester, and be followed closely throughout pregnancy and through the first year postpartum. Eye exams can be considered every 2 years if there has been no evidence of retinopathy, annually if retinopathy is present and more frequently if it is progressing or sight is threatened. Retinal photography with remote reading by experts can be cost effective.

Recommendations to reduce the risk or slow the progression of retinopathy include optimizing glucose and blood pressure control. Risk reduction has occurred through more timely diagnosis of type 2 DM, as well as intensified therapies for hyperglycemia, hypertension, and dyslipidemia.

Treatment is based on the stage of retinopathy. Nonproliferative diabetic retinopathy (NPDR), also known as background retinopathy, is an early stage where the retinal vessels begin to leak fluids. Proliferative diabetic retinopathy (PDR) describes weak new blood vessels developing that can burst and cause severe vision loss and blindness. Diabetic macular edema (DME) is swelling of the macula from blood vessels in the retina leaking fluid. The macula is responsible for central, detailed vision.

Laser photocoagulation therapy reduces vision loss. Treatments are done in the doctor's office. Focal therapies can stop or slow bleeding and fluid leakage. Scatter therapy shrinks the abnormal blood vessels through burning and scarring. A vitrectomy may be done to remove fluid and blood or scar tissue. These therapies reduce further vision loss, but usually cannot do anything for loss that has occurred.

Vascular endothelial growth factor (VEGF) is a protein that may contribute to the development of new weak, fragile blood vessels. Anti-VEGF medicines may help decrease their development. Lucentis (ranibizumab injection) is an example of a neutralizing antibody to VEGF that may improve vision and reduce the need for photocoagulation. Others include Eylea (aflibercept), Avastin (bevacizumab), and Macugen (pegaptanib). There is also the potential for sustained intravitereal delivery of fluocinolone and prevention with fenofibrate that is being explored by the National Eye Institute.

For your patients concerned about retinopathy, encourage the following:

1. Maintain good blood glucose, blood pressure, and cholesterol levels.

2. Early identification, treatment, and follow-up has been the key to saving sight. There is a 95% reduction in severe vision loss with this plan.

3. Review the following Web sites for additional information:National Eye Institutehttp://www.nei.nih.gov/health/diabetic/retinopathy.aspNational Diabetes Information Clearinghousehttp://diabetes.niddk.nih.gov/dm/pubs/complications_eyes/index.htm

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