Orbital emphysema develops after an orbital fracture in a three-step process. After the fracture has occurred on one of the orbital walls, a sino-orbital communication is established. The communication will allow air to be forced from the sinuses into the orbit in the presence of a pressure gradient from forceful expiratory efforts, nose-blowing or even a sneeze. Orbital emphysema is typically a harmless disorder because air escapes as quickly as it enters the fracture site, and the increase in intraorbital pressure is usually transient, lasting for as long as the sneeze or nose blowing. However, when orbital soft tissues, such as fat, falls back on the sino-orbital communication, a one-way ball valve will be created, leading to the entrapment of air. When sufficient air accumulates, it will result in acute compartment syndrome and vascular compromise, causing complications including proptosis, visual impairment, central retinal artery occlusion, compressive optic neuropathy, and other severe complications caused by orbital compartment syndrome.
