The Medical Minute: Preventing diabetes-related blindness

March 03, 2004

Blindness from Diabetic Retinopathy is Preventable
By David A. Quillen, M.D., associate professor and interim chair for ophthalmology
Penn State Milton S. Hershey Medical Center

The statistics are alarming: individuals with diabetes mellitus are 25 times more likely than the general population to become blind. Diabetes mellitus affects approximately 18 million people in the United States. It is the leading cause of new blindness among adults between 20 and 74 years of age, with 12,000 to 24,000 new cases of blindness occurring each year. Fortunately, there is good news in the fight against blindness from diabetes. Early detection combined with appropriate general medical and eye care can significantly reduce the risk of vision loss related to diabetes.

Diabetic retinopathy is the leading cause of vision loss in people with diabetes. Diabetic retinopathy is divided into two categories: nonproliferative and proliferative. Nonproliferative diabetic retinopathy is characterized by abnormalities of the retina including microaneurysms, intraretinal hemorrhages, cotton wool spots, macular edema and lipid exudates. The most common cause of vision loss in nonproliferative diabetic retinopathy is macular edema. Proliferative diabetic retinopathy is characterized by the proliferation of blood vessels as a result of widespread circulation abnormalities within the retina. These abnormal blood vessels may result in severe hemorrhages and scar tissue formation within the eye.

Diabetic retinopathy does not occur in isolation but is impacted by the overall general medical status of a person with diabetes. The onset and severity of diabetic retinopathy is influenced by many factors, including the duration of diabetes, the quality of diabetes control, high blood pressure, lipid abnormalities, kidney disease and fluid overload states (e.g., congestive heart failure). Improvement in the control of these factors may be associated with a substantial reduction in the risk of blindness from diabetic retinopathy.

One of the biggest challenges is that people with diabetic retinopathy may not experience symptoms of vision loss. That's why it's critical that people with diabetes get regular comprehensive eye examinations to promote early detection and treatment. The American Academy of Ophthalmology (AAO) has established a recommended eye examination schedule for individuals with diabetes. For those with type 1 diabetes (diabetes diagnosed before the age of 30), the AAO recommends that a comprehensive eye examination be performed annually beginning five years after the diagnosis of diabetes. This reflects the low incidence of significant diabetic retinopathy in individuals with less than five years of diabetes.

The time of onset of type 2 diabetes (diabetes diagnosed after 30 years of age) is difficult to determine precisely. As a result, significant diabetic retinopathy may be observed in individuals with type 2 diabetes at the time of diagnosis or shortly thereafter. The AAO recommends that a comprehensive eye examination be performed at the time of diagnosis for individuals with type 2 diabetes. Because diabetic retinopathy may progress during pregnancy, eye examinations should be performed prior to conception or early in the first trimester of pregnancy.

Several studies have confirmed the benefit of intensive diabetes management in reducing the development and progression of diabetic retinopathy. Therefore, the most important thing individuals with diabetes can do to reduce the risk of blindness from diabetic retinopathy is to control their blood glucose levels and address associated medical problems, such as high blood pressure and lipid abnormalities. When diabetic retinopathy occurs, surgical options are available. Laser photocoagulation has proven to effectively reduce the risk of vision loss for diabetic macular edema and proliferative diabetic retinopathy. Since laser photocoagulation works best at preventing future vision loss, early detection is key!

Blindness from diabetic retinopathy is a devastating complication from diabetes mellitus. Fortunately, most cases of blindness can be prevented with intensive control of blood glucose levels and effective management of associated medical problems. Regular comprehensive eye examinations are essential to promote the early detection and treatment of diabetic retinopathy. With proper care and follow up, individuals with diabetes may enjoy a lifetime of excellent vision.

(Media Contacts)

Last Updated March 19, 2009