The diagnosis of giant-cell arteritis (GCA) is straightforward in textbook cases in which an elderly patient presents with temporal headache, scalp tenderness, classic jaw claudication (ie, crescendo pain with chewing), and sudden loss of vision. However, this diagnosis comes up far more frequently in the differential diagnosis for variations of these symptoms such as atypical headache, transient vision loss, double vision, or even the incidental finding of an elevated sedimentation rate, platelet count, or C-reactive protein. This of course is particularly true when trying to make the diagnosis early to prevent the dreaded outcome of permanent vision loss (incidence in GCA is 15% to 30% of cases). Eye doctors in particular need to maintain a high level of vigilance, as 20% of GCA patients present with only ophthalmologic complaints.