Orbital hematoma and blindness can occur during or after sinus surgery. All orbital hematomas in 3500 endoscopic sinus ethmoidectomies were identified and evaluated for type, treatment, and sequelae. Fifteen orbital hematomas were identified, with 1 case of temporary blindness and no cases of permanent blindness. Two types of orbital hematoma were identified-slow (venous) and fast (arterial)-which differ in management. The venous type results from penetration of the lamina papyracea and disruption of veins. The arterial hematoma is caused by anterior or posterior ethmoid artery injury. The treatment approach to each is different, with blindness more likely occurring from a fast (arterial) hematoma. Of the 2 types of orbital hematoma that can occur during sinus surgery, surgical decompression and hemorrhage control are more likely with the fast arterial hematoma, which has not been the subject of any prior presentation. Cause and management of each will be discussed.