Evaluation of Single Nucleotide Polymorphisms (SNPs) in Patients With and Without Diabetic Macular Edema

Background: \- Diabetic macular edema (DME) is a common condition in people with diabetes. DME occurs when blood vessels in the eye leak fluid, resulting in swelling inside the back of the eye and progressive vision loss. Research has shown that good blood sugar control can reduce the risk and severity of DME. However, not all diabetic patients with poor blood sugar control develop DME, and some patients develop DME despite excellent blood sugar control. This suggests that other factors, such as genes or inherited traits, may predispose or protect a diabetic patient from developing DME. Objectives: \- To investigate genetic factors that may influence the development of diabetic macular edema. Eligibility: \- Individuals at least 18 years of age who have type 2 diabetes, with or without diabetic macular edema. Design: * The study will require one visit to the National Institutes of Health eye clinic. * Participants will be screened with a medical history and basic eye examination. Individuals who have certain eye diseases other than DME may not be allowed to enroll in the study. * Participants will provide a blood sample, and will receive fluorescein angiography (an injection of fluorescein dye, after which a camera will take pictures of the dye as it flows through the blood vessels in the eye). * No treatment will be provided as part of this protocol.