[Acute diplopia after the age of 50; always look for giant cell arteritis].

Although giant cell arteritis (GCA) is a rare cause of ophthalmoplegia, swift diagnosis and treatment are necessary to avoid other complications. We report here a case of GCA in a 59-year-old woman with a history of hypertension and thyroid lobectomy. Diagnosis resulted from binocular diplopia, although classical GCA symptoms had been present a few days before. Oral corticotherapy led to a rapid disappearance of headaches and normal ocular motility in 1 month. We discuss the ophthalmological signs of the disease and the place of temporal artery biopsy and treatment.