ABSTRACT
The intimate relation between the paranasal sinuses and the orbit places the orbital contents at risk of injury during ESS (endoscopic sinus surgery). This injury may cause severe postoperative orbital complications. These have been widely reported from mild orbital hematoma to devastating visual loss. Despite technological advances with a skillful surgeon, ESS still carries potential risks of direct injury to the orbital contents and optic nerve, which may cause blindness. In our case, the disturbance in visual acuity developed 14 days after ESS without intraoperative orbital complications. And we report a rare case of posterior ischemic optic neuropathy following ESS, which may be presumed to cause the delayed onset blindness postoperatively.