Temporal Arteritis With Arteritic Anterior Ischemic Optic Neuropathy is Bilateral Until Proven Otherwise: Response

We thank Singh et al (¹) for their remarks regarding our recent case report (²). We agree with them that: 1) timely diagnosis and treatment of giant cell arteritis (GCA) is crucial, 2) pallid swelling of the optic disc is evidence of optic nerve infarction rather than simply ischemia, 3) detection of bilateral optic nerve disease is due to GCA (or at least something more than straightforward nonarteritic anterior ischemic optic neuropathy) until proven otherwise, and, as in both their patient and ours, 4) bilateral involvement in patients with GCA may be extremely asymmetric clinically, at least from the standpoint of visual function. In such cases, the presence of a “small” or “2/4” relative afferent pupillary defect in a patient with what seems to be a severe unilateral ischemic optic neuropathy should raise the specter of bilateral optic nerve involvement and lead to consideration of GCA.