<unk>  occurs following forceful injection of air into the soft tissues of the orbit through a breach in one of the<unk>  walls which is typically associated with<unk>  fracture after blunt trauma, or less frequently with compressed air injuries, tumours and infections of the sinonasal region or complications after surgery.<unk>  develops after an<unk>  fracture in a three-step process. After the fracture has occurred on one of the<unk>  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.<unk>  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<unk>  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<unk>  compartment syndrome. There are three variations of<unk> , namely palpebral<unk> , true<unk> , and orbitopalpebral<unk> . Palpebral<unk>  Palpebral<unk>  refers to<unk>  of the eyelids alone. It is a rare kind of<unk>  which is usually caused by fractures of the lacrimal bone. The lacrimal sac ruptures as a result of the fracture, allowing air from the nasal cavity to enter the tissues of the eyelid. Alternatively, facial subcutaneous air may simply pass into the eyelids along fascial plane to produce palpebral<unk> . As long as the<unk>  septum is intact, air is confined in the eyelids. True<unk>  True<unk>  occurs when there is air behind an intact<unk>  septum. This condition arises due to a fracture of more than one bony<unk>  walls of paranasal sinuses and tearing of adjacent sinus mucosa, and communication of a sinus with the orbit is established. This fracture usually involves the ethmoid, and sometimes involves frontal, sphenoid, and maxillary sinuses. The air usually enters the orbit when the pressure within the upper respiratory tract is increased due to expiratory efforts, nose blowing or sneezing. Orbitopalperbal<unk>  Orbitopalpebral<unk>  refers to the trapping of air inside both the soft tissues of the orbit and the eyelid. It is usually a sequelae of a true<unk> . When too much air accumulates inside the orbit, the<unk>  septum ruptures due to high intraorbital pressure. Air may then pass freely from the orbit into the eyelids through the break in the<unk>  septum.
Orbital emphysema
Tympanites
Trachoma
Orbital blowout fracture
Orbital apex syndrome
Orbital cellulitis
Vitreous hemorrhage
Periocular injection