Darrin Landry, CRA, OCT-C, our photographer here at EMG, wrote this for our patients to help in explaining diabetic retinopathy. Darrin has been an ophthalmic photographer for 22 years, 8 of those years with EMG.
“Wide field image of diabetic retinopathy.
Note the hemorrhages scattered throughout (arrows)”
Diabetic retinopathy is a collective term that refers to conditions of the retina as a result of diabetes. The retina is the innermost layer of the back of the eye that is responsible for sensing light and converting light to electrical signals to the brain. When sugar levels are too high in the blood, damage to the blood vessels in the retina can occur. This results in leakage of blood or leakage of serous fluid, which is the clear part of blood. When blood vessels leak into the retina, it swells or forms deposits that can interfere with normal vision.
An example of this is called macular edema, which is swelling or thickening of the central part of the retina that allows for fine detail vision. This is the most common cause of visual loss in diabetes. Macular ischemia, or lack of oxygen in the central part of the retina, occurs when the smaller capillaries in the eye close down and results in a loss of oxygen to that part of the retina. When the body senses that no oxygen is reaching these parts, it starts to form new blood vessels, called neovascularization. These new blood vessels do not supply the needed oxygen to the retina, and in fact can cause more problems. The new blood vessels are fragile and can break and bleed into the vitreous, which is the fluid that fills the back of the eye, and cause dramatic sudden vision loss. They can also scar and contract the retina, causing retinal tears or detachments.
Ischemia can also prompt the growth of new blood vessels in the colored part of the eye, called the iris, and cause a severe, blinding type of glaucoma. In cases of macular edema, or swelling, injections of a medication may be indicated to reduce the edema. Laser treatment may also be necessary to decrease the fluid leakage, and in most cases the goal is to prevent more damage or loss of vision.
In areas of ischemia, or lack of blood supply, the doctor may recommend laser treatment to eliminate the demand for oxygen in that area of the retina. Laser can also be applied to neovascularization, to shrink the vessels and decrease the chance of bleeding.
In advanced cases of diabetic retinopathy, surgery may be necessary, either to remove blood from the vitreous or to repair retinal tears or detachments. Prevention is the best treatment for diabetic retinopathy. Strict control of blood sugars and frequent monitoring by yourself and your doctor can significantly reduce the long-term risk of vision loss from diabetic retinopathy. Early detection is crucial for a better prognosis and reduced risk of vision loss. Annual dilated eye exams are recommended for anyone with diabetes, and more frequent visits to the eye doctor may be necessary if you are experiencing any visual problems or are already diagnosed with diabetic retinopathy.