Cystoid Macular Edema

Overview

Macular edema refers to the presence of fluid in the central portion of the retina called the macula. There are numerous conditions that may lead to macular edema, including diabetic retinopathy and retinal vein occlusion. The term cystoid macular edema (CME) usually refers to a specific entity in which macular edema occurs after cataract surgery, although other causes of inflammation within the eye may also lead to CME.

Cystoid macular edema typically occurs within a few weeks to several months following cataract surgery. It is more likely to occur if there was a complication during surgery, or in patients already predisposed to its development, such as patients with diabetes, a history of intraocular inflammation, or an episode of CME in the other eye at the time of cataract surgery. It is important to note, however, that CME may develop after an operation that went perfectly well.

It is believed that cystoid macular edema develops because of the release of chemical mediators of inflammation, which is part of the body's normal response to surgery. These chemicals cause the retinal blood vessels to become leaky, and fluid can then start to accumulate within the macula. The term "cystoid" refers to the frequent development of cysts within the macula.

Signs and Symptoms

• blurry central vision
• distortion of vision

To aid in the diagnosis of CME, a fluorescein angiogram may be performed. This is a test in which a dye is injected into a vein in the arm, and photographs are taken as the dye travels through the retinal blood vessels. In patients with CME, dye will be seen leaking out of the blood vessels around the macula.

Treatment

In the majority of patients, CME will resolve on its own and vision will return to normal. Treatment, if necessary, typically involves the use of topical steroidal and non-steroidal eyedrops. If not successful, an injection of steroids may be given around the eye.