By Yan Liu Baum, MD, Kaiser Permanente Tacoma South Medical Center
“Mary” is a very fit woman in her early fifties who is just slightly overweight. She has been a patient of mine for the last 10 years. For the first 5years, Mary’s diabetes was not very well controlled. She did not like to come to the doctor’s office regularly since she felt fine. She takes metformin (Glucophage) and glipizide (Glucotrol). Mary refused insulin since she does not like injections. We talked about ways to better manage her diabetes mellitus (DM) including scheduling regular diabetic vision tests but she preferred to stay the course with no changes. Because, overall, she felt fine, she could see very well, and her life is very busy, she did not want to do anything differently. Mary asked why she would even need a vision exam?
That was five years ago. Then one day, Mary scheduled an office visit with me to follow up from a recent emergency room trip. Mary had become blind and it happened very fast. Mary had no warning signs. Her hemoglobin A1C (a three-month average of the blood glucose levels) was 11, very high. While at the emergency room, the hospital started Mary with insulin injections and she became ready to control her diabetes.
This time, she believed what physicians had been telling her: diabetes does not always cause symptoms, but uncontrolled diabetes can make people suffer serious complications such as blindness.
Diabetes is a metabolic disorder where blood sugar is high for a long period of time due to lack of insulin or insulin resistance. There are no obvious symptoms (although you may have frequent urination and increased hunger and thirst). That is why we regularly screen patients for diabetes. Family medical history plays a role, but some people with diabetes have no family history. Lifestyle factors, such as diet, weight, activity, stress patterns and more play a role in developing diabetes.
High blood sugar can lead to many major complications like stroke, diseases, nerve problems, cardiovascular disease, foot ulcers, infections or loss of vision.
Right now, we would like to explore more about visual changes related to diabetes. Vision loss for diabetes patients can be a drastic change. For Mary, suddenly everything in front of her eyes became dark. With uncontrolled diabetes, even if your vision was perfect yesterday, a decline in vision and even blindness can occur overnight.
Why does high blood sugar cause blindness?
The retina is the sensor at the back of our eye. With uncontrolled diabetes, blood sugar is too high, and the high concentration of sugar starves the sensitive retina cells of oxygen. The retina responds by growing small new blood vessels, capillaries, to help it draw more oxygen from the blood. These new blood vessels are very fragile – they can bleed and lead to a clot, scar, or cause the retina to become detached. The fragile blood vessels can inflate or dilate, like a balloon – and one day the balloon pops. There is bleeding on the retina, and blindness can result.
To prevent the blindness or poor vision from diabetes, patients should get their vision screened regularly. At Kaiser Permanente, because we feel it is so important, we set up a diabetic retinal screen machine at the office to make things as convenient as possible. So, our patients can have a retinal exam any time they come in for a visit. The exam photo is sent to the eye doctor electronically for analysis. The patient will be called in for further eye treatment if needed.
Mary learned a lot from her personal experience. Her diabetes is currently managed very well. She has been using insulin for five years and is maintaining her current weight. Her A1C level has gone down from 11 to a stable 6.5. She is very grateful that she was able to recover some of her vision and she does not want to repeat same problem in the future. She also tells many of her friends and coworkers her story and encourages them to have regular vision exams if they have diabetes, even if they have perfect vision.