If you have diabetes mellitus, your body does not use and store sugar properly. High blood-sugar levels can damage blood vessels in the retina, the nerve layer at the back of the eye that senses light and helps to send images to the brain. The damage to retinal vessels is referred to as diabetic retinopathy.

Types Of Diabetic Retinopathy

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 this stage, tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposites call exudates. NPDR usually does not affect vision. When vision is affected it is the result of macular edema (swelling of the macula, the area that allows us to see fine details clearly) and/or macular ischemia (when small blood vessels close).

PDR is present when abnormal new blood vessels 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. Unfortunately, the new abnormal blood vessels do not resupply the retina with normal blood flow. The new vessels are often accompanied by scar tissue that may cause wrinkling or detachment of the retina.

PDR may cause more severe vision loss than NPDR because it can affect both central and peripheral vision.

How Is Diabetic Retinopathy Diagnosed And Treated? 

All diabetics should have a yearly eye exam to screen for retinal disease.  This exam should include dilating your pupils so the doctor can check the entire retina.  In the early part of the disease it is often watched for progression without treatment.  If you have macular edema or new blood vessel growth, you may be a candidate for laser treatment.  Laser treatment is aimed at sealing the leaky blood vessels or regressing abnormal blood vessel growth.  The majority of vision loss from diabetes is preventable with timely laser treatment.  Newer experimental treatments involving injections into the eye are also available and have been shown to benefit patients with diabetic retinopathy.  In advanced cases, surgery is sometimes indicated to remove blood or scar tissue.