Diabetic retinopathy

Diabetic Retinopathy

Diabetic retinopathy is a condition that occurs when diabetes affects the blood vessels and nerve tissue in the retina.

There are two stages of diabetic retinopathy:

Nonproliferative retinopathy is the early stage of the disease in which blood vessels swell and leak.  In some cases, this can cause macular edema (swelling of the retina) which may result in mild vision loss but can be treated.  There can also be early changes to the nerve cells in the retina that may affect vision, in part due loss of adequate blood supply.

Proliferative retinopathy is the advanced stage where abnormal new blood vessels grow on the surface of the retina. These vessels may break and bleed into the vitreous, the clear watery gel that fills the eye, and cause severe vision loss. This stage of diabetic retinopathy typically requires urgent treatment.

While diabetic retinopathy often cannot be completely prevented, you can reduce your risk of having it develop or progress. Controlling your blood sugar slows the start of retinopathy and prevents it from getting worse. It also lessens the need for laser surgery or other procedures that treat severe retinopathy.

Causes 

Diabetic retinopathy is caused by having high blood glucose levels for long periods of time. Prolonged bouts of high sugar glucose levels can weaken and damage the small blood vessels within the retina. This may cause hemorrhages, exudates and even swelling of the retina. Over time, the retina eventually becomes starved of oxygen and abnormal blood vessels start to grow. Good blood glucose control helps to lower diabetic retinopathy risks.

Symptoms 

You will not usually notice diabetic retinopathy in the early stages, as it does not tend to have any obvious symptoms until it's more advanced. However, early signs of the condition can be picked up by taking photographs of the eyes during diabetic eye screening.

Contact your GP or diabetes care team immediately if you experience:

• gradually worsening vision
• sudden vision loss
• shapes floating in your field of vision (floaters)
• blurred or patchy vision
• eye pain or redness
• difficulty seeing in the dark

Diagnosis

Diabetic retinopathy is best diagnosed with a comprehensive dilated eye exam. For this exam, drops placed in your eyes widen (dilate) your pupils to allow your doctor a better view inside your eyes. The drops can cause your close vision to blur until they wear off, several hours later.

During the exam, your eye doctor will look for abnormalities in the inside and outside parts of your eyes.

Fluorescein angiography

After your eyes are dilated, a dye is injected into a vein in your arm. Then pictures are taken as the dye circulates through your eyes' blood vessels. The images can pinpoint blood vessels that are closed, broken or leaking.

Optical coherence tomography (OCT)

With this test, pictures provide cross-sectional images of the retina that show the thickness of the retina. This will help determine how much fluid, if any, has leaked into retinal tissue. Later, OCT exams can be used to monitor how treatment is working.