CME, or cystoid macular edema, is a painless disorder of the central retina or macula. When CME is present, multiple cyst-like areas of fluid appear in the macula and cause swelling of the retina, or edema. The exact causes of CME are unknown, but it does accompany a variety of diseases such as retinal vein occlusion, uveitis, age related macular degeneration, or diabetes. CME has also been linked to eye injury and can be a side effect of medication. CME most commonly occurs after cataract surgery. If a patient gets CME in one eye, there is up to a 50% that it will affect the second eye.
Symptoms of CME included blurred or decreased central vision; however, most patients recover their vision with treatment. The treatment for CME varies depending on what appears to have caused it. Retinal inflammation can be treated with anti-inflammatory medications that include steroid eye drops, pills, or local injections. Diuretics can help reduce the swelling in some cases. If the vitreous is believed to be the source of the issue, then surgery to remove the vitreous, called a vitrectomy, may be required. CME can bring on glaucoma; if this happens, the glaucoma must be treated with medications to reduce pressure.