Diabetes Awareness Month: How to avoid serious eye diseases

Adult Cardiologist Consultant at Lagos Executive Cardiovascular Centre

How does diabetes affect my eyes?

Diabetes affects your eyes when your blood glucose, also called blood sugar, is too high.

You are not likely to have vision loss from high blood glucose. People sometimes have blurry vision for a few days or weeks when they are changing their diabetes care plan or medicines. High glucose can change fluid levels or cause swelling in the tissues of your eyes that help you to focus, causing blurred vision. This type of blurry vision is temporary and goes away when your glucose level gets closer to normal.

If your blood glucose stays high over time, it can damage the tiny blood vessels in the back of your eyes. Such damage can begin during prediabetes, when blood glucose is higher than normal, but not high enough for you to be diagnosed with diabetes. Damaged blood vessels may leak fluid and cause swelling. New, weak blood vessels may also begin to grow. These blood vessels can bleed into the middle part of the eye, lead to scarring, or cause dangerously high pressure inside your eye.

Most serious diabetic eye diseases begin with blood vessel problems. The four eye diseases that can threaten your sight are

Diabetic retinopathy

The retina (which is the inner lining at the back of each eye) senses light and turns it into signals that your brain decodes, so you can see the world around you. Damaged blood vessels can harm the retina, causing a disease called diabetic retinopathy. In early diabetic retinopathy, blood vessels can weaken, bulge, or leak into the retina. This stage is called non-proliferative diabetic retinopathy.

If this gets worse, some blood vessels close off, which causes new blood vessels to grow, or proliferate, on the surface of the retina. This stage is called proliferative diabetic retinopathy. These abnormal new blood vessels can lead to serious vision problems.

Diabetic macular edema

Diabetes can lead to swelling in the macula (the part of your retina that you need for reading, driving and seeing faces), which is called diabetic macular edema. Over time, this disease can destroy the sharp vision in this part of the eye, leading to partial vision loss or blindness. Macular edema usually develops in people who already have other signs of diabetic retinopathy.