IOIS Views 5 meanings found IOIS most often refers to a rare eye condition marked by unexplained inflammation of the orbital tissues, and the same letters are also used for professional societies and research institutes focused on ocular inflammation. Medical Idiopathic Orbital Inflamatory Syndrome Miscellaneous Imaging of Intrinsic Signals Governmental Institute of Investigative Science Academic & Science International Ocular Inflammation Society International Ocular Inflammaion Society