Diabetes and Diabetic Eye Disease

Created on: Wednesday, November 16, 2016

The United States has one of the highest rates of diabetes among all developed countries. According to the Centers for Disease Control (CDC), 29 million or 9.3% of the population has diabetes. Approximately 8 million people have diabetes, but don’t know they have it. The CDC further reports that 86 million people in the US have prediabetes and one third of these people will go on to develop diabetes. In fact, one in three Americans will develop diabetes in their lifetime. All of these numbers are growing at alarming rates. Diabetic eye disease is the number one cause of blindness in working-aged Americans. In addition to affecting the eyes, diabetes can cause problems with the kidneys, heart, brain, feet and nerves. Most of these complications, however, can be prevented with proper management and treatment.

What is diabetes?

Much of what we eat and drink is broken down into glucose. This glucose is transported throughout the body via the blood to cells where it is used by muscles for energy or stored as fat. These cells require insulin to allow glucose to enter the cells. In diabetes, there is a problem in getting this glucose into the cells so the glucose remains in the blood. The elevated blood sugar damages blood vessel walls leading to leaky blood vessels and reduced blood flow to your body’s organs. Diabetes is diagnosed by one of several tests measuring blood glucose levels. Fasting blood glucose of over 125 mg/dl or casual blood glucose of over 200 mg/dl or hemoglobin A1c of over 6.5%. Prediabetes is defined as a casual blood glucose level of 140-199 mg/dl.

Types of diabetes

Type I diabetes occurs when the insulin producing cells in the pancreas have been damaged and produce little or no insulin. This type of diabetes is usually discovered in people younger than 20.

Type II diabetes occurs when our body resists the effect of insulin or the body does not produce enough insulin. This type of diabetes is most common in people over 45 years of age.

How does diabetes affect the eye?

The retina is the thin layer of neural tissue that lines the back of the eye and it contains the photoreceptors that send visual signals to the brain. The macula is the small area of the retina responsible for our most acute vison for reading, driving and seeing fine detail. The retina requires a lot of blood flow through retinal and sub-retinal blood vessels to transport nutrients for normal function. When chronically high levels of blood glucose are present, the retinal blood vessel walls are damaged so that they leak blood or result in poor blood flow. This is called diabetic retinopathy. The early stages of diabetic retinopathy are called non-proliferative. This includes aneurysms, hemorrhages or leaking of blood fluid called exudates. There can also be swelling of the retinal tissue called cotton wool spots due to lack of adequate blood flow. The more advanced stage of diabetic eye disease is called proliferative diabetic retinopathy. This is characterized by growth of abnormal new blood vessels (neovascularization). These new blood vessels break and bleed and they provide the highest risk of vision loss. The number one cause of blindness in diabetics is when these blood vessels cause swelling of the macula (macular edema)

How is diabetic eye disease treated?

The best way to avoid diabetic eye disease and to manage early diabetic retinopathy is to control your blood glucose level, control blood pressure, control cholesterol levels, eat a healthy diet, exercise regularly and avoid smoking. If vision is threatened by more advanced diabetic eye disease, retinal specialists can treat the disease with lasers and/or eye injections. A very important key to success is timely diagnosis and intervention. Therefore, it is very important for all diabetics to have a dilated retinal exam every year or even more often if you have visual symptoms.


 Dr. Greg Kraupa Dr. Greg Kraupa, OD