Orbital infection or inflammation can be vision threatening. They present very similarly. However, one can be life threatening in addition to causing blindness. The cause of orbital infection is usually bug bite, orbital trauma or surgery, or extension of pre-existing facial infection, while the cause of orbital inflammation is unknown. The signs and symptoms include swelling of the eyelids and soft tissues of the socket, including orbital fat and muscles, proptosis (bulging of the eye), restrictive eye movement, conjunctival injection and edema, decreased vision, increased intraocular pressure, pain, and double vision. A work-up that includes CT scan of the orbit with and without contrast is necessary to help discern between these two conditions and many others that may also present similarly and to determine the severity of the condition. The history of how the condition develops also helps to distinguish between these two conditions and others. Additional tests may be required to look for underlying autoimmune conditions associated with orbital inflammation. Treatment for orbital infection is systemic antibiotic, and treatment for orbital inflammation is high-dose systemic steroid. In some cases steroid-sparing agent (prescribed by rheumatology) or radiation may be necessary to completely calm the inflammation.