Understanding diabetic retinopathy — and taking steps to prevent it

Diabetes — the disease characterized by high blood glucose (or blood sugar) — is a common health condition that can have devastating effects on people's lives. Unlike with many other conditions, those with diabetes have an enormous amount of control on how diabetes affects them. People with diabetes can take action to reduce the harmful damage diabetes can cause to the blood vessels, heart, kidneys, nerves, and eyes.

Diabetes is widespread in the United States. In California, 10 percent of the adult population has been diagnosed with diabetes, 33.4 percent of adults have prediabetes (meaning their blood glucose levels are elevated and they are at increased risk for diabetes), and 884,000 people have diabetes but don't know it, according to the American Diabetes Association.

One serious damaging effect of diabetes is diabetic retinopathy, a condition that can cause vision loss and even blindness. The retina is the part of the eye that detects light. Diabetic retinopathy occurs when the blood vessels of the retina are damaged by elevated sugar levels in the blood. The longer a person has diabetes or the less controlled their blood sugar is, the more likely they are to develop diabetic retinopathy.

To detect diabetic retinopathy, all patients with diabetes should have a yearly comprehensive eye exam with dilation. In a dilated eye exam, the doctor administers eye drops that cause the pupils to widen and allow the doctor to better see the back of the eye. When medical providers detect diabetic retinopathy, they will recommend treatments to better control the patient's blood sugar; treatments may include lifestyle changes, medication, or both.

Doctors use A1C tests, also known as hemoglobin A1C or HbA1c tests, to evaluate the level of sugar in the blood. The AIC is a blood test that measures the patient's average blood sugar over the past three months. The A1C results show the percentage of the patient's red blood cells that have sugar-coated hemoglobin. Hemoglobin is the protein in red blood cells that delivers oxygen to the body's tissues. A1C results are used to diagnose diabetes or prediabetes, and to help patients with diabetes to manage it. A normal A1C level is 5.7 percent or below. Prediabetes is characterized by an AIC level of 5.7-6.4 percent, and diabetes is diagnosed when the A1C level is 6.5 percent or above. Higher A1C levels are linked to more diabetes complications.

In its early stages, diabetic retinopathy can develop without any symptoms. This is why the annual dilated eye exam is so important to early detection. Patients should also contact their doctor if they experience spots or strings in their vision (floaters), blurred vision, changing vision, dark or empty areas in their field of vision, or vision loss.

Sometimes patients get busy and skip regular exams, which can have serious consequences. I saw a patient recently whose A1C level was normal a year ago. This year, it was 14 percent — double the normal level. It went from nothing to something significant very quickly. Someone like that is at risk for a really quick progression to retinopathy. Better outcomes come from early detection followed by careful diabetes management.

Patients with diabetes or prediabetes should take steps to manage their blood sugar. By working together with their medical provider, they can identify and reach a healthy A1C goal. As a rule, those with diabetes or prediabetes should eat a diet low in carbs and sugar, limit or eliminate alcohol, and should not smoke. The extent to which carbohydrates should be limited depends on the patient's A1C level. Regular physical activity also helps to lower blood sugar. Patients with diabetes or prediabetes should work with their doctors to develop a workable and effective plan, which may also include medication.

Those who don't have a primary care provider can reach out to a federally qualified health center like MCHC to establish one. For a dilated eye exam, patients without existing eye issues can see an optometrist without a referral. Those with existing eye issues can be referred to an ophthalmologist by their primary care provider.

Patients don't always take their diabetes seriously, but when they realize it can lead to vision loss or even blindness, that tends to be a wakeup call. Prevent vision loss by carefully managing your diabetes and scheduling a dilated eye exam each year.