Diabetic Retinopathy

Overview

Diabetic retinopathy is a diabetes condition that affects the eyes. It's caused by damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina). There are two types of diabetic retinopathy: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).

NPDR, commonly known as background retinopathy, is an early stage of diabetic retinopathy in which tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposits called exudates. Many people with diabetes have mild NPDR, which usually does not affect their vision. When vision is affected it is the result of macular edema, macular ischemia or both. Macular edema is swelling or thickening of the macula, a small area in the center of the retina that allows us to see fine details. While it’s the most common cause of visual loss in diabetes, peripheral vision still continues to function. Macular ischemia is when small blood vessels (capillaries) close and the macula no longer receives sufficient blood supply to work properly.
PDR is present when abnormal new vessels (neovascularization) begin growing on the surface of the retina or optic nerve. The main cause of PDR is widespread closure of retinal blood vessels, preventing adequate blood flow. The retina responds by growing new blood vessels in an attempt to supply blood to the area where the original vessels closed. PDR may cause more severe vision loss than NPDR because it can affect both central and peripheral vision.

Symptoms

You might not have symptoms in the early stages of diabetic retinopathy. As the condition progresses, diabetic retinopathy symptoms may include:

Spots or dark strings floating in your vision (floaters)
‍Blurred vision
Impaired color vision
‍Fluctuating vision
‍Vision loss
Dark or empty areas in your vision

Diabetic retinopathy usually affects both eyes.

Causes

When blood sugar levels are too high 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, called ischemia. These problems are signs of non-proliferative diabetic retinopathy (NPDR).

As diabetic eye problems are left untreated, proliferative diabetic retinopathy (PDR) can develop. Blocked blood vessels from ischemia 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. Neovascularization can even lead to glaucoma, damage to the optic nerve that carries images from your eye to your brain.

Maintaining strict control of blood sugar and blood pressure, as well as having regular diabetic retinopathy screenings by your eye doctor are keys to preventing diabetic retinopathy and vision loss. Controlling blood sugar and also help to prevent the development of cataracts, as diabetes is a risk factor for cataracts.

Diagnosis

An ophthalmologist can often diagnose and treat serious retinopathy before you are aware of any vision problems. The ophthalmologist dilates your pupil and looks inside of the eye with special equipment and lenses.

If your ophthalmologist finds diabetic retinopathy, special tests may be ordered such as colored photographs of the retina or a fluorescein angiography to find out if you need treatment. In this test a dye is injected into your arm and photos of your eye are taken to detect where fluid is leaking.

Treatment

The best treatment is to prevent the development of retinopathy as much as possible. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss from diabetic retinopathy. If high blood pressure and kidney problems are present, they need to be treated.

‍Medical Treatment – In certain cases, your ophthalmologist may choose to treat your macular edema with injections of medicine in your eye. These special shots of medicine, called intravitreal injections, may be steroids or other medications. They are designed to shrink the swelling of the macula.
‍Laser Surgery – This is often recommended for people with macular edema, PDR and neovascular glaucoma. For macular edema, laser surgery is used to prevent further loss of vision. For PDR, laser surgery is used to shrink abnormal new vessels and prevent them from future growth. Laser surgery does not cure diabetic retinopathy and multiple treatments over time are sometimes necessary.
‍Virectomy – In advanced PDR this procedure may be recommended. A virectomy involves removing the blood-filled vitreous and replacing it with a clear solution. Your ophthalmologist may wait several months to see if the blood clears on its own before performing a virectomy.

Additional Information

National Eye Institute (NEI)

Mayo Clinic

Source:

Mayo Clinic

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