What is Cystoid Macular Edema?
The healthy retina is a very thin tissue, which lines the back of the eye. The retina functions as the film in the back of the camera. The central portion of the retina is called the macula. This area provides all of the sharp central vision for activities such as reading and driving. This area is very delicate and can develop swelling, or “edema”, when it is irritated. This swelling makes the macula look bubbly or “cystic”, hence the name cystoid macular edema, or “CME”.
Who Gets Cystoid Macular Edema?
Cystoid macular edema can occur in different conditions and is seen occasionally in patients who have had previous eye surgery. Only a small percentage of people who have had cataract or other eye surgery will develop cystoid macular edema. The swelling may occur many months or even years after the surgery. It can occur with all types of cataract surgery and with any type of lens implant. Cystoid macular edema may occur despite perfect surgery without any complications.
CME may also occur as a result of inflammation inside the eye, or from weak blood vessels as in diabetes or with blocked retinal veins. Inflammation can result from infection, autoimmune inflammation (called “uveitis”), trauma, or other irritating stimuli. Cystoid macular edema may occasionally develop for no apparent reason.
What Are the Symptoms of Cystoid Macular Edema?
Patients with cystoid macular edema frequently notice their reading vision is blurred. The peripheral or side vision remains unchanged. Frequently, people with cystoid edema notice distortion of objects and dimness. In addition, eyes may appear irritated and red, may water a great deal, and may even be tender to the touch.
How is Cystoid Macular Edema diagnosed?
If cystoid edema is suspected, a picture test called a fluorescein angiogram may be performed. During the test, color photographs of the retina are taken, after which a yellow dye is injected into an arm vein. Photographs of the retina following dye injection indicate pooling of dye in the macula in a distinctive pattern, confirming the diagnosis of cystoid macular edema. Sometimes, the cystoid edema can be seen without the need for angiography.
What Treatments Are Available for Cystoid Macular Edema?
Depending on the severity and the cause, cystoid macular edema may be treated in a number of ways. If the swelling has resulted from an observable problem, such as an infection, then treating the cause may help. Edema from diabetes is often treated with laser to seal leaky diabetic vessels. If a problem related to previous surgery is detected, such as a piece of leftover retained cataract, additional surgery may be performed to resolve this issue.
Usually, initial treatment for simple postoperative macular edema consists of using anti-inflammatory eyedrops, sometimes along with an over-the-counter anti-inflammatory pill, such as Aleve TM. If this is not adequate, anti-inflammatory steroid injections may be placed around the eye, or given in high doses intravenously. In rare cases, the vitreous jelly, in the back of the eye, may be removed in an attempt to decrease irritation or tugging on the back of the retina. If the edema is felt to be due to irritation from a lens implant, that implant may need to be surgically removed or exchanged for another style of implant.
Steroid medications can sometimes cause abnormal elevation of pressure in the eye, requiring additional medications to control this pressure. For this reason, use of these medications must be watched closely. Cystoid macular edema usually responds well to treatment, although response may require several months of continuing treatment. In rare cases, cystoid macular edema, and vision loss, persists in spite of all treatment attempts. Your doctor will discuss your individual case with you.