Cystoid macular edema (CME) is a condition in which there is edema or swelling in the macula. This swelling collects in multiple fluid filled cysts in the retinal tissue and thus has been named “cyst-like” macular edema. This swelling in the macula causes the vision to be blurred. There is no pain, and the condition exhibits no external symptoms, such as bloodshot eyes.
There are two general mechanisms that can cause CME. One cause is inflammation. Inflammation can be caused by an eye injury, eye surgery, or a number of eye diseases.
The other cause is vitreous traction. Normally, the vitreous (the jelly like substance which fills the eye) is loosely attached to the retina. However, in some patients, CME arises from a tugging effect on the macula by this vitreous.
There are various treatments for CME. To address the inflammatory cause, medications such as steroids can be administered orally, topically, or injected in or around the eye. In some cases, steroid treatment results in dramatic improvement and the patient recovers good vision, but in other cases there is little or no improvement. In these cases, other medications, such as non-steroidal anti-inflammatory drugs, may prove beneficial.
If the eye fails to respond to medical treatment, and there is evidence that the vitreous is tugging on the macula, a surgical procedure called vitrectomy can be performed to eliminate the tugging vitreous. As in the case of steroid treatment, some patients respond very well to the surgery and recover good vision, while others experience little or no improvement.
CME that has been present for two years or longer may have produced irreversible changes in the macula. Even if treatment is not successful, or the macula is damaged severely enough so that central vision becomes very low, peripheral or side vision is almost always maintained so that mobility is not affected. In general, people do not go blind, even in the most severe cases.