Causes:
(1) trauma or surgery with hemorrhage
(2) orbital inflammation (cellulitis, pseudotumor)
(3) severe orbital emphysema
(4) thyroid orbitopathy
Clinical features:
(1) sudden proptosis (exophthalmos) over a period of minutes to hours
(2) difficulty opening the eyelids
(3) chemosis (conjunctival edema), which may be hemorrhagic
(4) ocular pain
(5) nausea and vomiting
(6) decreased ocular motility
(7) elevated intra-ocular pressure (> 40 mm Hg)
(8) decreased visual acuity which may progress to acute vision loss
(9) relative afferent pupillary defect
If the pressure continues to increase without relief, then ocular ischemia and optic neuropathy may develop,
