The Link Between A1c Levels and Retinopathy

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The A1c is at the core of modern blood glucose management. It provides a rough measure of the average blood glucose value over a three-month period, and is one of the ways that a doctor measures your blood sugar control.

People with diabetes tend to have a higher A1c than the average person. This is because the A1c takes into account the blood sugar swings that happen during the day when the person eats.

After a meal, the body absorbs glucose from the carbohydrates consumed. As the blood sugar levels rise, insulin kicks in and helps to transport the glucose to the body’s organs and cells to provide them with energy. In a healthy person, the pancreas senses the rise in blood sugar and secretes enough insulin to counteract it. In a person with diabetes, they are either unable to produce insulin or utilize it effectively, depending on the type of diabetes they have.

If a diabetic does not balance their medications with the amount and type of carbohydrates being consumed, blood sugar levels can rise higher than normal. Each time this happens, the high blood sugar levels lead to a higher A1c.

The A1c and Diabetic Complications

The A1c is connected to diabetic complications, since it is an indicator of prolonged periods of high blood sugar which causes diabetic complications. People with diabetes are generally encouraged to try and keep their A1c below 7. This number is the result of studies, such as the Diabetes Control and Complications Trial, a long-term study of the health complications of people with type 1 diabetes. One thing that the trial accomplished was to link the A1c levels of people with diabetes to the complications that they had over their lives. In general, a lower A1c is connected to fewer complications.

Diabetic Retinopathy is Connected to A1c Levels

One of the complications of diabetes is diabetic retinopathy. The link between A1c levels and diabetic retinopathy is clear. A higher A1c leads to a higher risk of retinopathy. Higher blood glucose levels damage blood vessels. Retinopathy means that the tiny blood vessels in the eye are damaged. This can lead to leaking and swelling of these blood vessels or the growth of new, unnecessary blood vessels. Spotty vision, blurred vision and even vision loss can be the result.

Other Variables Also Contribute to the Progression of Diabetic Retinopathy

The link between A1c levels and diabetic retinopathy is not conclusive because there are other variables that come into play. Good control of blood pressure and cholesterol also promotes good overall health and reduces complications.

Genes also change the link between A1c levels and diabetic retinopathy. As with everything in your body, some of the complications from diabetes are genetic. Some people may be more prone to suffering from neuropathy in their feet, while others may suffer kidney damage. Other people seem to have no complications at all for a long time, even if their A1c is higher than they would like it to be. However, overall, a higher A1c does tend to predispose people to complications in the future.

Addressing Diabetic Retinopathy

To address diabetic retinopathy, it is also very important to go to the eye doctor for regular check ups. There are now treatments for diabetic retinopathy, and although they are not perfect, checking for small bleeds in the eyes is an important proactive step in your health care. This can help address complications as they arise and hopefully prevent the retinopathy from getting more severe.


Irl B. Hirsch, MD; Michael Brownlee, MD. 2010. Beyond Hemoglobin A1c-Need for Additional Markers of Risk for Diabetic Microvascular Complications: Commentary.

National Diabetes Information Clearinghouse. DCCT and EDIC: The Diabetes Control and Complications Trial and Follow-up Study.

National Eye Institute. Facts About Diabetic Retinopathy Defined.