Orbital compartment syndrome: An ophthalmic emergency

A 55-year-old male presented to the emergency department with severe right eye pain, redness, and decreased vision. He reported a history of blunt trauma to the eye two days prior. On examination, the eye showed proptosis, with chemosis and decreased extraocular movements.

An urgent orbital CT scan was performed. The contrast-enhanced CT demonstrates findings highly suggestive of orbital compartment syndrome. There is marked proptosis of the left eye with anterior and cranial displacement of the globe (Figure 1a). Two fluid collections are noted, one in the pre-septal region and another in an extraconal location with dehiscence of the inferior orbital wall (Figure 1b) and fracture (Figure 1c). The optic nerve is significantly stretched and straightened, indicative of elevated intraorbital pressure. The posterior globe exhibits a characteristic “tenting of the posterior wall of the eye”, suggesting advanced compartment syndrome (Figure 2). Preseptal soft tissues are markedly oedematous. The patient underwent emergency surgery for drainage. One month post-surgery, there was significant improvement (Figure 3).

Background

Orbital compartment syndrome (OCS) is a critical ophthalmic emergency marked by elevated pressure within the orbital cavity, which impairs the perfusion of the optic nerve and the globe. This condition can lead to irreversible visual impairment if not addressed urgently. The orbit, an anatomical space surrounded by bony structures, contains the eye and its associated tissues. Any increase in volume within this confined space—whether from haemorrhage, inflammation, or neoplasm—results in elevated intraorbital pressure, adversely affecting the optic nerve and vascular structures. This increased pressure impairs blood flow and oxygen delivery, potentially causing irreversible damage due to both vascular compromise and mechanical stretching of the optic nerve, especially in cases of acute proptosis (i.e., trauma, bleeding, infection, abscess, or inflammation) [1,2].

Clinical Perspective

Patients with OCS commonly exhibit decreased visual acuity, pronounced proptosis, ocular pain (particularly with eye movement), limited ocular motility, and tense, oedematous eyelids. Additional signs may include dilated pupils or pupils with sluggish light reactions [3]. The clinical challenge is the rapid progression of the optic nerve and globe damage if OCS is not promptly managed. Imaging is indispensable for confirming the diagnosis, delineating the radiological manifestations of OCS, and identifying underlying aetiologies such as retrobulbar haematoma, infection, neoplasm, or emphysema. Accurate imaging data on the cause, extent, and severity of OCS is critical for directing treatment and evaluating therapeutic response [2,3].

Imaging Perspective

Computed tomography (CT) is the preferred initial imaging modality due to its rapidity, accessibility, and efficacy in visualising bony structures and detecting foreign bodies. While magnetic resonance imaging (MRI) provides superior soft tissue evaluation, it should not delay intervention in cases with a high clinical suspicion of OCS. Key imaging findings include proptosis, posterior globe “tenting” (i.e., inferior to the normal angle range, which is between 134° and 164°, with a mean of 150º, which indicates globe compression), and optic nerve stretching [2,3]. Other findings related to the underlying cause may encompass haematoma, abscess, neoplasm, or emphysema. Although imaging is crucial for OCS assessment, the definitive diagnosis remains clinical, based on patient history and physical examination [3,4].

Outcome

Management of OCS necessitates prompt intervention to alleviate intraorbital pressure and prevent irreversible damage to the optic nerve and globe. Emergency surgical procedures such as lateral canthotomy and inferior cantholysis are essential for initial decompression. Additionally, addressing the underlying cause is necessary, which may involve haematoma or abscess drainage, antibiotic therapy for infection, or surgical resection of a neoplasm [1,4]. The prognosis depends on the severity of intraorbital pressure elevation, duration of optic nerve compression, and promptness of diagnosis and intervention. Early diagnosis and treatment are crucial for preserving vision.

All patient data have been completely anonymised throughout the entire manuscript and related files.