A Pilot Study for the Evaluation of Minocycline as a Microglia Inhibitor in the Treatment of Diabetic Macular Edema Clinical Protocol support contract designed to attain extramural support for developing, designing, interpreting, and evaluating clinical trials, epidemiologic and natural history studies. In addition, it will provide for outcomes research involving eye diseases and visual disorders and some preclinical studies. The focus shall be on the design of studies and the collection, analysis, and interpretation of data emanating from these studies, as well as support, and monitoring patient safety and follow-up. Contractor shall also provide analytical and data management support, as described in the work statement, for specified clinical research data bases, cost-effectiveness and economic analyses, quality of life assessment and outcomes research. This will include, but not be limited to, the following areas: analysis of Medicare and other health care databases;evaluation of existing NEI databases such as, centralized NEI Intramural Research database, the Eye Disease Case Control Study, Early Treatment Diabetic Retinopathy Study, Framingham Eye Study, and intramural AIDS and uveitis databases. Objective of Clinical Protocol: - Diabetic retinopathy, or damage to the small blood vessels at the back of the eye, is a frequent complication of diabetes, and is a leading cause of blindness. Diabetic retinopathy can lead to swelling within the eye, known as diabetic macular edema which causes vision loss. - Chronic inflammation has been implicated in diabetic macular edema. Microglia are cells in the retina involved in inflammation in the retina. For these reasons, microglia represent a promising cellular target for forms of therapy that limit the harmful inflammatory changes found in diabetic retinopathy. Minocycline, a drug that is currently approved for use as an antibiotic, may be able to inhibit microglia and thus reduce their contribution to chronic inflammation. Researchers are interested in examining whether minocycline may be used to treat or slow the progress of diabetic macular edema. Objectives: - To test the safety and effectiveness of minocycline as a treatment for diabetic macular edema.