Cystoid macular edema is an eye disorder in which small pockets, or cysts, of fluid build up in the center of the retina. In most cases, fluid buildup is the result of broken or leaking blood vessels in the eye. Cataract surgery is a leading cause of cystoid macular edema due to incidental damage to retinal blood vessels. Many other conditions, including trauma, diabetes, and viral infections can also precede the disorder. Blurry vision and other symptoms usually go away on their own within a few weeks, but persistent cases may need to be treated with eye drops or occasionally surgery.
The macula is a small spot in the middle of the retina that focuses central vision. There are hundreds of tiny blood vessels around the macula that, if damaged, can leak fluid and create yellow cysts. The condition is usually painless, though central vision can be significantly impaired. A person might have trouble focusing on objects or text directly in front of them. Peripheral vision is typically left intact.
Surgical procedures to reattach an injured retina or clear up cataracts may result in cystoid macular edema. Following a delicate operation, the immune system instinctively triggers a mild chemical response to help the eyes heal. Resulting inflammation can damage blood vessels and possibly cause them to break open. Most instances of post-surgical cystoid macular edema resolve on their own without treatment in two to three weeks as the eyes continue to recover.
A person may also develop cystoid macular edema following an eye injury or infection. Diabetes is a notable risk factor as well, as the disease is known to impair retinal blood vessels. In addition, some prescription medications including those for glaucoma and certain types of cancer can also trigger cystoid macular edema.
An eye doctor can usually diagnose the condition during a routine eye exam. If it is unclear whether swelling and multiple cysts are present, an x-ray procedure called a fluorescein angiogram can be performed. A fluorescent dye is injected into the bloodstream, where it disperses itself throughout blood vessels in the eyes. X-ray images can track the movement of the dye to see if vessels are leaking into the macula.
Treatment for persistent cystoid macular edema depends on the underlying cause. When infections and diabetes are treated accordingly, symptoms usually clear up quickly. Medicated eye drops or injected solutions may be administered to relieve inflammation and shorten healing time. If other treatments fail, surgery to cauterize blood vessels and remove damaged tissue can be considered.