Mary Summers, MD
Diabetic Retinopathy
People who have been diagnosed with diabetes should have yearly dilated exams with an ophthalmologist.
Diabetic retinopathy occurs when blood vessels in the retina are damaged. Sometimes these vessels swell and leak fluid or even close off completely. In proliferative diabetic retinopathy, abnormal new blood vessels grow on the surface of the retina.
The retina is a thin layer of light-sensitive tissue that lines the back of the eye. Light rays are focused onto the retina, where they are transmitted to the brain and interpreted as the images you see. The macula is the central part of your retina. It is the macula that is responsible for your pinpoint central vision, allowing you to read, sew or recognize a face. The surrounding part of the retina, called the peripheral retina, is responsible for your side—or peripheral—vision.
Diabetic retinopathy usually affects both eyes. People who have diabetic retinopathy often don't notice changes in their vision in the disease's early stages. But as it progresses, diabetic retinopathy usually causes vision loss that in many cases cannot be reversed.
Diabetic Retinopathy Causes
When blood sugar levels are elevated for extended periods of time, it can damage capillaries (tiny blood vessels) that supply blood to the retina. Over time, these blood vessels begin to leak fluids and fats, causing edema (swelling). Eventually, these vessels can close off causing ischemia (decreased perfusion of tissue i.e. retina). These problems are signs of non-proliferative diabetic retinopathy (NPDR).
If diabetic retinopathy is left untreated, proliferative diabetic retinopathy (PDR) can develop. Retinal ischemia caused by damaged blood vessels can lead to the growth of new abnormal blood vessels on the retina (called neovascularization) which can damage the retina by causing wrinkling or retinal detachment.
Maintaining strict control of blood sugar and blood pressure, as well as having regular diabetic retinopathy screenings by your ophthalmologist, are essential to preventing diabetic retinopathy and subsequent vision loss. Controlling blood sugar can also help to prevent the development of cataracts, as diabetes is a risk factor for cataracts.