ADVM-022 Intravitreal Gene Therapy for DME

Inclusion Criteria: * Age ≥ 18 * Type 1 or Type 2 diabetes mellitus * Willing and able to provide informed consent * Vision impairment due to center involving diabetic macular edema Exclusion Criteria: * Uncontrolled diabetes defined as HbA1C \>10%, or history of diabetic ketoacidosis within 3 months prior to randomization; or subjects who, within the last 3 months, initiated intensive insulin treatment (a pump or multiple daily injection) or plan to do so in the next 3 months. * Acute coronary syndrome, myocardial infarction or coronary artery revascularization, CVA, TIA in the last 6 months * Uncontrolled hypertension defined as average SBP ≥160 mmHg or an average DBP ≥100 mmHg * Known severe renal impairment * High risk Proliferative Diabetic Retinopathy * History of retinal disease in the study eye other than diabetic retinopathy * History of retinal detachment (with or without repair) in the study eye * History of vitrectomy, trabeculectomy, or other filtration surgery in the study eye * Any prior focal or grid laser photocoagulation or any prior PRP in the study eye * Current or planned pregnancy or breastfeeding