Diabetes is a disease that affects the body’s ability to produce or use insulin effectively to control blood sugar (glucose) levels. Although glucose is an important source of energy for the body’s cells, too much glucose in the blood for a long time can cause damage in many parts of the body, including the heart, kidneys, blood vessels and the small blood vessels in the eyes.
Diabetes can cause vision in both eyes to change, even if you do not have retinopathy (damage to the retina). Rapid changes in your blood sugar alter the shape of your eye's lens, and the image on the retina will become out of focus. After your blood sugar stabilizes, the image will be back in focus. You can reduce episodes of blurred vision by maintaining good control of your blood sugar.
There are three types of diabetes. Type 1 diabetes is usually diagnosed in children and young adults. Previously known as juvenile diabetes, it occurs when the body does not produce insulin. The most common form of diabetes is type 2 diabetes. In this case, either the body does not produce enough insulin or the body's cells ignore the insulin. In gestational diabetes, blood sugar levels become elevated during pregnancy in women who have never had diabetes before. Gestational diabetes starts when the mother's body is not able to make and use all the insulin it needs during pregnancy.
People with any type of diabetes can develop hyperglycemia, which is an excess of blood sugar, or serum glucose. A chronic elevation of serum glucose causes damage throughout the body, including the small blood vessels in the eyes.