Orbital compartment syndrome after a penetrating traumatic incident

Dear Editor,
Orbital compartment syndrome (OCS) is an ophthalmic surgical emergency that both emergency physicians and trauma surgeons should be familiar with. The orbit is an enclosed space with limited capacity to expand. In addition, the eyeball and the retro-bulbar space are wrapped in a continuous cone-shaped fascial envelope which is contained on all sides by 7 rigid bones, except anteriorly, where the orbital septum and eyelids form another less flexible boundary [1, 2]. OCS is one of the few ophthalmic surgical emergencies occurring when a sharp increase in confined volume within the orbit results in an acute increase in orbital strain. Normal intraocular pressure is between 3 and 6 mm Hg (0.4–0.8 kPa). The orbit is able to compensate for small increases in orbital volume with anterior globe movement and fat prolapse; however, large and rapid increases in pressure are not tolerated, resulting subsequently in an acute ischemic process. The volume of the orbital content is around 30 mL, including the eyeball, vessels, nerves, fat, muscles and the lacrimal glands. Although the orbit is not a fully confined space, it follows the pressure-volume dynamics with a pathophysiology similar to other compartment syndromes [1, 3].
In OCS, impairment of the optic nerve and retina can develop rapidly, causing irreversible loss of vision. Studies suggest that 60 to 100 min of elevated intraocular pressure may lead to permanent visual sequelae [4]. Common causes include acute orbital hemorrhage due to trauma, surgery, local injections, and pre-existing medical conditions. There are other important etiologies such as fulminant orbital cellulitis or infra-orbital abscess, orbital emphysema, inflammation, and tumors. Less commonly, prolonged hypoxia with capillary permeability, foreign material in orbit, massive volume replacement after burning, or position-dependent edema may result in an acute increase in orbital pressure [1, 5].
In cases of trauma, retro-bulbar hematoma is the most common cause of OCS. Hemorrhage in this case usually results from the lesion of the infraorbital artery or one of its branches often associated with complex facial fractures of the Le Fort II and III type [4, 5].
The diagnosis of OCS is clinical and early recognition with subsequent emergency orbital decompression is essential to prevent permanent loss of vision [1]. Anamnesis and physical examination are obviously essential, but in a trauma setting, anamnesis is...


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