A 63 year old female with Grave's disease presents with a 6 day history of "cold" symptoms and 3 day history of a red and painful left eye (OS). She says that she occasionally noticed scanty yellowish discharge from the eye.
On examination her visual acuity was 20/20 OD and 20/60 OS (pinhole). Visual fields to confrontation were normal. Her pupils were equal in size, but there was a relative afferent pupillary defect OS. Extraocular movements were painful OS. Funduscopy appeared normal.