Orbital compartment syndrome (OCS) is a rare cause of blindness following intracranial surgery. We report a patient with OCS following intracranial cerebrovascular surgery precipitated by severe straining. OCS occurred due to a rapid increase in intraorbital pressure within the rigid confines of the orbit causing hypoperfusion of critical neural structures, which resulted in visual loss and a complete external ophthalmoplegia. Treatment involved urgent surgical soft tissue decompression of the orbit, corticosteroids and osmotic agents. It is important to consider OCS as a cause of blindness in the neurosurgical postoperative setting as without rapid treatment this condition has a very poor prognosis.