Scheie Eye Institute, University of Pennsylvania
People with age-related macular degeneration (AMD) sometimes hear the words “macular edema” and wonder what it is and whether it might affect them. Learn more about macular edema and how it is related to macular degeneration.
Edema anywhere in the body refers to fluid that has leaked out of blood vessels and caused tissue swelling. In people who have diabetic retinopathy (a complication of diabetes that affects eyes), the term is typically used to refer to fluid that has accumulated within the macula, which is the central part of the retina. In people with AMD, similar fluid within the retina is more typically called “intraretinal fluid.”
Macular edema is a condition that occurs when fluids build up within the macula, the central area of the retina most critical for vision. The buildup of fluid causes the macula to swell, disrupting its normal shape. This results in damage to vision. The symptoms of macular edema include blurred vision, distortion of images, missing areas, or a change of contrast in vision. Left untreated, the swelling can cause these vision problems to progressively worsen. If any of these vision problems occur, speak with an eye care professional immediately.
In both diabetic retinopathy and AMD, blood vessels are encouraged to leak by a protein called vascular endothelial growth factor, or VEGF. The retina makes extra VEGF in these diseases because it’s not getting enough oxygen, or because it is inflamed. However, the VEGF does not help because it causes the blood vessels to leak fluid that accumulates between nerve cells in the retina. In the short term, this fluid diminishes retinal function, and in the long term, it is associated with the death of some of the retinal cells.
Macular edema or intraretinal fluid can cause distortion or “graying-out’ of central vision.
It helps to use a special graph called an “Amsler grid” to monitor for macular edema at home. The grid looks like a piece of graph paper with a small dot in the center. A person with macular edema will often see some of the grid lines as curved or even blocked out by a gray, white or black region.
The fluid can be seen by ophthalmologists during a dilated eye exam, and measured using an imaging device called optical coherence tomography (OCT).
Fortunately, macular edema or intraretinal fluid can often be treated using anti-VEGF drugs. Currently, these include Avastin®, Lucentis®, Eylea®, and Beovu®. Additionally, long-lasting anti-VEGF gene therapy is being tested in clinical trials.
People with ocular inflammation can also develop macular edema. This can occur following cataract surgery, or in people with autoimmune diseases. In cases of ocular inflammation, the macular edema is usually treated with anti-inflammatory, steroid, or immunosuppressive drugs.
To reduce the risk of developing macular edema, adopt a healthy lifestyle. For diabetics, and those with AMD or autoimmune diseases, lowering systemic inflammation is helpful. This can be done by avoiding smoking, engaging in moderate exercise, and eating a diet rich in vegetables and fruits. Fatty fish like salmon twice a week also seems to be protective. Refined grains, sugars, starches, highly processed foods and meats increase inflammation. For diabetics, it is also very important to control blood sugars.
In summary, macular edema is the build-up of fluid within the central part of the retina. Macular edema or intraretinal fluid can temporarily or, if long-standing, permanently diminish central vision. The risk of accumulating this unwanted fluid can be reduced with a healthy lifestyle and it can be treated with anti-VEGF drugs, sometimes with laser for those with diabetes or anti-inflammatory or immunosuppressive drugs for those with autoimmune diseases.
Joshua Dunaief, MD, received his BA magna cum laude in Biology from Harvard (1987), MD/PhD from Columbia College of Physicians and Surgeons (1996), completed ophthalmology residency at the Wilmer Eye Institute, Johns Hopkins in 2000, and medical retina fellowship at Scheie Eye Institute, University of Pennsylvania in 2004.
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