Laboratory Studies
No laboratory studies are absolutely indicated in the workup of patients with acute orbital compartment syndrome (AOCS). Baseline routine laboratory evaluation may be requested for a patient who requires urgent medical treatment or urgent surgical decompression or to evaluate for use of anticoagulation therapy.
Imaging Studies
CT scanning or MRI of the orbit may help to identify the etiology of compression and to exclude alternative diagnoses. The radiological sign often associated with AOCS is a posterior angle of the eye inferior to 130° (“globe tenting”), observed in 75% of cases. [11] Additionally, some evidence correlates severe findings with prognosis of visual loss. [14] While ultrasonography has not been validated for AOCS, studies have shown its diagnostic utility in evaluating for alternative traumatic ocular pathologies, including retinal detachment, central retinal artery occlusion (CRAO), lens dislocation, vitreous hemorrhage, and vitreous detachment. [15]
Other Tests
Once globe rupture has been excluded, IOP should be promptly measured. Normal IOP pressure ranges from 10-20 mm Hg, with an acceptable difference between each eye of 3-6 mm Hg. [13] Pressures greater than 40 mm Hg should be promptly treated (see Treatment). The examination is not static and should be repeated with any changes in pain or symptoms or periodically in high-risk patients.
-
Lateral canthotomy is performed by incising laterally with sharp scissors.
-
Cantholysis is performed by identification and disinsertion of the inferior crus of the lateral canthal tendon, which should allow free mobility of the lower lid margin.
