2Department of Ophthalmology, Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK; 3Department of Surgery & Cancer, General Surgery, Faculty of Medicine,Imperial College London, London, UK Correspondence: Vickie Lee Department of Ophthalmology, Western Eye Hospital, Imperial College Healthcare NHS Trust, 153– 173 Marylebone Road, Marylebone, London, NW1 5QH, UK Tel +44 20 3312 6666 Purpose: There is no universal consensus on second-line agents for the treatment of moderate/severe to sight-threatening thyroid eye disease (TED) to maintain remission after first-line intravenous methylprednisolone (IVMP). This study investigates the efficacy and safety of mycophenolate mofetil (MMF) in TED patients in a real-world setting and over a longer period than previous randomized controlled trials.