Diabetic Macular Edema

One of the most frequent causes of vision impairment in the United States and throughout the rest of the world is diabetic retinopathy. Diabetic retinopathy is a complication of diabetes that causes damage to the blood vessels of the retina. The longer someone has diabetes, and the less their blood sugars are controlled, the higher the possibility that person will develop diabetic retinopathy. There are two causes of vision loss from diabetic retinopathy: diabetic macular edema and proliferative diabetic retinopathy.

Diabetic macular edema

Swelling in the central part of the retina occurs. It is nourished by blood vessels that are weakened or begin to leak as a result of diabetes. This causes the central part of the retina to thicken or swell to lead to decreased vision.

Proliferative diabetic retinopathy

When diabetes damage the small blood vessels in the retina, resulting in poor circulation to the retina. Vision may be lost because some of the retina tissue may dies as a result of this inadequate blood supply. Retina tissue can not grow back once it is lost. Poor circulation associated with diabetes may lead to the development of growth factors that can cause new blood vessels and scar tissue to grow on the surface of the retina. This stage of diabetic retinopathy referred to as "proliferative" because at this stage of the disease, new, abnormal blood vessels and scar tissue begin to grow on the surface of the retina. The vessels bleed into the middle cavity of the eye, causing vision loss because light cannot reach the retina. Scar tissue formation can also pull on the retina, detaching it from the back of the eye, resulting in vision loss.

It is possible to have diabetic retinopathy for a long time without noticing symptoms until damage has occurred. Some patients may experience a partial or total loss of vision. Some other symptoms include: blurred or double vision, difficulty reading, appearance of spots (floaters), shadow across the field of vision, eye pain or pressure, and difficulty with color perception.

The primary cause of diabetic retinopathy is diabetes. Diabetes can damage the small blood vessels that nourish the retina and may block them completely in some cases. The blood supply to the retina from these damaged blood vessels is cut off and vision is affected.

Risk

• High blood pressure
• High cholesterol levels
• Length of time individual has diabetes
• Poor control of blood sugar levels over time
• Pregnancy in someone with diabetes

Diagnosis and treatment

Diagnostic options include:

• Eye Exam-the best way to diagnose diabetic retinopathy. Dilation will occur to help get a better view of the inside of the eye, especially the retina tissue.
• Fundus Photography- photographs taken of the back of the eye to facilitate detection and to document the retinopathy
• Fluorescein Angiography- retinal photography test. The pictures are taken of the retina, allowing the physician to accurately detect blood vessels that are closed, damaged, or leaking fluid.
• Optical Coherence Tomography- provides cross-sectional images of the retina that show its thickness, helping determine whether fluid had leaked into retinal tissue.

Treatment options include:

• Surgical treatments- lasers to the retina or injections of medications into the middle cavity of the eye. Can be done in office or hospital setting to prevent, treat, or reverse damage from diabetes in the retina. The key to these treatments is the blocking by eye injections of vascular endothelial growth (VEGF). VEGF is a chemical signal in the body that stimulates blood vessel growth. Repeated doses of anti-VEGF medications may be needed to prevent blood vessels from leaking fluid and causing damage to the eye.
• Proper Examination- with proper examinations, the earliest signs of diabetic retinopathy in the retina can be detected before vision loss begins. Regular dilated eye exams by an ophthalmologist are important, especially for those who are at a higher risk for diabetic retinopathy or diabetes.

Prevention

• Control blood pressure
• Control blood sugar
• Control lipid levels
• Follow eye exam schedule

Regular dilated eye exams may not prevent diabetic retinopathy, but it certainly can reduce the risk of developing more severe complications from the disease. By detecting it early, the retina specialist can begin treatment regimen to help prevent vision loss and slow the disease's progression.