Diabetes Mellitus is an inability to utilize and store sugars within the blood. This inability can alter blood flow to the eye. This lack of blood flow to the eye can injure retinal blood vessels causing leakage of blood and fluid within the macula as well as the growth of abnormal blood vessels within the retina which can bleed causing sudden visual loss.
Two forms of diabetic retinopathy exist: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).
NPDR is an earlier stage of diabetic retinopathy in which small blood vessels within the retina leak blood and fluid. Sometimes this leakage of blood and fluid can cause macular edema. Macular edema causes permanent visual loss, which can be progressive over years if not addressed early. A more severe form of macular edema can arise from macular ischemia in which small blood vessels supplying the macula "shut down" destroying central vision.
PDR can arise later in the development of diabetic retinopathy in which abnormal growth of blood vessels can cause sudden visual loss when bleeding occurs. These vessels may also scar down with traction placed onto the retina causing a retinal detachment. Both of these effects may affect vision significantly and permanently.
Symptoms of diabetic retinopathy consist of intermittent or permanent blurry vision, floaters, and central vision defects.
If recommended by your retina specialist treatment of diabetic retinopathy is performed utilizing laser therapy consisting of focal or panretinal photocoagulation. Focal laser therapy targets the "leaky" blood vessels by sealing off the source of the blood or fluid. This treatment is painless and performed in one setting in the office. Panretinal photocoagulation requires more than treatment in the office and can be associated with some discomfort. Panretinal photocoagulation places scattered laser spots throughout the peripheral retina in order to decrease the demand for production of abnormal blood vessels. Laser surgery does not improve vision usually but rather save vision for the diabetic patient.
Occasionally the abnormal blood vessels bleed extensively or scar down with a tractional retinal detachment, requiring microsurgery called vitrectomy. A vitrectomy is performed in the operating room and involves microsurgical removal of blood in the eye as well as repair of a tractional retinal detachment.
Patients with diabetes mellitus should schedule an eye examination at least once a year or more if directed by your retina specialist. Pregnant women should schedule an examination during the first trimester secondary to the risk of progression of diabetic retinopathy from the pregnancy. Early detection of diabetic retinopathy is the best protection from blindness.