What is Diabetic Retinopathy?
Diabetic retinopathy is a complication of diabetes caused by changes in the blood vessels of the eye. If you have diabetes, your body does not use and store sugar properly. High blood sugar levels create changes in the veins, arteries and capillaries that carry blood throughout the body. This includes the tiny blood vessels in the retina, the light-sensitive nerve layer that lines the back of the eye.
There are two forms of diabetic retinopathy: non-proliferative and proliferate.
Non-proliferative diabetic retinopathy (NPDR) is an early stage of diabetic retinopathy consisting of edema and hard exudates, lipid that has leaked from abnormal blood vessels, in the central retina, resulting in blurred central vision.
In the later stages of diabetic retinopathy, known as proliferative diabetic retinopathy (PDR), retinal blood vessels are so damaged they close off. In response, the retina grows new, fragile blood vessels. Unfortunately, these new blood vessels are abnormal and grow on the surface of the retina, so they do not resupply the retina with blood. Occasionally, these new blood vessels leak and cause a vitreous hemorrhage.
Blood in the vitreous, the clear gel-like substance that fills the inside of the eye, blocks light rays from reaching the retina. A small amount of blood will cause dark floaters, while a large hemorrhage might block all vision, leaving only light and dark perception. The new blood vessels can also cause scar tissue to grow. The scar tissue shrinks, wrinkling and pulling on the retina and distorting vision. If the pulling is severe, the macula may detach from its normal position and cause vision loss.
How is Diabetic Retinopathy Treated?
The main treatment for NPDR is laser photocoagulation for macular edema. Many patients with significant macular edema are asymptomatic with good vision. It is therefore essential to diagnose and treat these patients during the early stage to prevent future visual loss.
For patients with PDR, anti-VEGF medications just as Avastin and Eylea, may be injected into the eye to decrease recurrent hemorrhages and treat neovascularizations. If the hemorrhage remains for a long period of time, a vitrectomy can be performed to remove the blood-filled vitreous with the aim of improving vision. Patients can also regain some vision if scar tissue is removed from the surface of the retina during the vitrectomy surgery.
Although we can’t prevent the occurrence of diabetic retinopathy, good medical control and early diagnosis and treatment of retinopathy can significantly reduce the progression to severe visual loss. People with diabetic retinopathy sometimes have no symptoms until it is too late to treat them. The retina may be badly injured before there is any change in vision. There is considerable evidence to suggest that rigorous control of blood sugar decreases the chance of developing serious diabetic retinopathy. Because diabetic retinopathy often has no symptoms, if you have any form of diabetes you should have your eyes examined regularly by an ophthalmologist.