Anisocoria may indicate a life-threatening neurosurgical emergency, unlike bilateral mydriasis. In patients with periorbital fracture, anisocoria can be caused by direct or indirect injury to the oculomotor nerve, excessive retraction of the orbital contents, or constriction of the muscles responsible for eyeball movement. Herein, the author reports a patient, 15-year-old boy, who developed anisocoria after an operation for a blowout fracture. The anisocoria was improved, self-limiting, and transient. The author has also reviewed the literature regarding anisocoria.