What is Macular Retinal Edema?
Macular retinal edmena is just one of several hundred known eye diseases and disorders.
The "macula" of the eye is the yellow central area of the retina. It is the part of the eye where sharp, straight-ahead vision occurs. When fluid and protein deposits build up within this portion of the retina, it begins to thicken and swell. This is referred to as "edema" and it causes vision problems.
There are two types or classifications of this disorder:
1. Cystoid Macular Edema (CME)
2. Diabetic Macular Edema (DME)
What causes cystoid macular edema?
Cystoid macular edema (CME) occurs when multiple cyst-like fluid areas appear in the macular (often called "cystoids"). It causes swelling, but it is painless disorder. The swelling affects the macula, the area where the sharpest vision normally occurs.
The fluid filled cysts in the macula end up causing blurred vision.
According to the University of Michigan Kellogg Eye Center, once one eye as CME, there is an increased risk (perhaps as much as 50%) that CME will develop in the second eye. The goods news is that most patients recover their vision with treatment when caught early.
What causes diabetes macular edema?
Diabetes macular edema is caused by leaking blood capillaries.
Growing blood capillaries in the eye are delicate and can bleed easily. Those who have had diabetes for years can develop this "retinopathy" that leads to vision loss. As fluid leaks into the center of the macula, it makes the macula swell which, in turn, blurs vision. Macular retinal edema can occur at any stage of diabetic retinopathy.
According to the National Eye Institute, roughly half of the those diabetics with "proliferative" retinopathy also have macular edema. Macular edema is the most common cause of vision loss in both proliferative, and non-proliferative diabetic retinopathy.
Can DME or CME cause long-term damage?
According to Dr. Eric Donnenfeld, Associate professor of ophthalmology, New York University, permanent damage occurs in the architecture of the retina the longer CME persists. If CME is caught early and treated, there is less risk of permanent damage and loss of vision quality.
The same holds true for DME. And, with diabetes being a lifelong health issue, the risk of damage is greater over time.
Macular edema and cataract surgery
Following cataract surgery, cystoid macular edema (CME) is an important thing to watch for. It is a common cause of decreased vision in patients who have had this surgery and it occurs much more frequently than either retinal detachment or endophthalmitis.
CME has been clinically recognized and described over 50 years ago. However, very little is known about it. The rate of occurrence after cataract surgery has been estimated to between 1-19%. However, some medical professionals have suggested it could be as high as 60-70%.
Why is there such a varying degree in estimates of CME occurrence after cataract surgery? David S. Rho, MD, clinical associate professor of ophthalmology, University of Medicine and Dentistry of New Jersey, offers the following explanation:
“I think we’re realizing that there are more subtle ways in which patients will complain about their vision when they, in fact, have bona fide CME.”
Research suggests that when significant macular edema present in diabetic eyes at the time of cataract surgery it is unlikely that it will resolve spontaneously after surgery. However, if significant macular edema arises after surgery in a diabetic eye, it will commonly resolve itself.